Dissertations / Theses: 'Fields of Research – 270000 Biological Sciences – 270500 Zoology'

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Waghorn, Tania Susanne. "Molecular and Ecological Aspects of Heliothis Armigera." Thesis, University of Auckland, 1999. http://hdl.handle.net/2292/522.

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The species status and host range of Heliothis armigera was investigated. DNA profiling, mitochondrial DNA sequencing, RAPD's, along with traditional morphological and crossing methods were used to investigate micro, macro and mega-population structuring. Thirty-six new host records were added, of which a number are important common weeds and crops. Mortality due to parasitoids and fungal infections were quantified on many host species. Genetic analysis of the COII and the AT-rich regions of the mitochondrial DNA showed very high levels of variation, as did the DNA profiling using the probes (CA)n and 33.15. The morphological analyses also showed variation, but to a lesser degree and without statistical significance. The variation found at all levels and in all aspects is discussed with respect to caterpillar host-plants and geographical location. All host-plant populations of caterpillars showed very high levels of genetic variability. However, the population of caterpillars found on Sulla (Hedysarium coronarium) was significantly more variable than those found on Lotus and Lucerne when compared using DNA profiling. The sequences obtained from the two mtDNA regions also showed considerable variation, a great percentage of which was uninformative. This variation did not allude to any structuring of caterpillar populations with respect to host-plant or geographical location. H. armigera is genetically a very variable species which does not equate with any population structuring present in the host-plant or geographical populations investigated here. This study has greatly increased the general understanding of this insect, and has elucidated a portion of the genetic makeup, but not helped in the development any new control methods.

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Haw, James. "Effects of Argentine Ant (Linepithema Humile) on Arthropod Fauna in New Zealand Native Forest." Thesis, University of Auckland, 2006. http://hdl.handle.net/2292/625.

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Although Argentine ant(Linepithema humile), a highly invasive ant species, has been in New Zealand for at least l4 years, little is known about their ecology and potential for invasion. Increasing spread and establishment of populations throughout New Zealand is disturbing because of the devastating impacts documented on native invertebrate biodiversity overseas. The primary aim of this study was to determine the impacts of Argentine ants on arthropods in native forest habitats in west Auckland. Pitfall traps at invaded and uninvaded sites were used to quantify ant and non-ant arthropod faunas. Argentine ants did not adversely affect native host ant communities. Moreover, two ant species appeared to be resistant to invasion. Argentine ant invasion reduced the abundance of a few orders of invertebrates while several taxa were more abundant in the presence of Argentine ants. Distribution and foraging activity of Argentine ant populations were monitored in this study from 2000-2003. Also, rate of spread was investigated to evaluate whether native forest habitats would be at risk from invasion. Measurements of foraging ant trails on monitored tree trunks revealed seasonal distribution patterns involving high activity in summer/autumn and low activity in winter/early spring. Argentine ants were found to be established primarily along the edge of the forest and did not invade into the interior of the forest during the study period. An Argentine ant poisoning operation on Tiritiri Matangi Island in January 2001 provided the opportunity to document the results of the eradication trial. In addition, pitfall traps placed at two treated sites and one untreated site were used to compare pre-poison and post-poison effects on ant and non-ant invertebrate communities. Fipronil baiting at 0.01% effectively reduced Argentine ants at the study sites and very few ants were observed in both tree count and pitfall trap recordings two months after poisoning. The invasion of Argentine ants on Tiritiri Matangi Island decimated native host ants and no recovery was detected throughout the study. Several groups of invertebrates appeared to benefit from the removal of Argentine ants while a few showed no detectable changes. Conservation implications resulting from the findings of this study are discussed Also, potential future research involving Argentine ants are outlined.

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Beck, Nancy Gunther. "Lepidopterous pests on vegetable brassicas in Pukekohe, New Zealand: their seasonality, parasitism, and management." Thesis, University of Auckland, 1991. http://hdl.handle.net/2292/1982.

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The vegetable brassicas of cabbage, broccoli, and cauliflower are grown in Pukekohe for the Auckland fresh-produce markets. These brassicas are attacked by three major lepidopterous pests: diamondback moth (DBM) (Plutella xylostella (L)) (Yponomeutidae), white butterfly (WB) (Pieris rapae (L.)) (Pieridae), and soybean looper (SBL) (Thysanoplusia orichalcea (F.)) (Noctuidae). Current grower strategy to combat these pests is calendar-scheduled insecticide applications. The goal of this thesis is to develop pest management alternatives. The seasonality of these three pests is discussed. DBM and WB are each under biological control by a larval and a pupal parasitoid, but this natural control is not sufficient to allow economic harvests in cabbage and was not synchronized. No parasitoids of SBL were found. The importation of additional natural enemies is discussed. A scouting system of the percent of cabbage plants infested coupled with an action threshold of. 15%-20% infested plants, resulted in good yields in field trials and allowed up to a 50% reduction in insecticide applications over the growth period when compared to a 14-day calendar schedule. Implementation of the 15% infested threshold in commercial cabbage fields resulted in up to an 83% reduction in insecticide applications with no yield decrease in quality or quantity. Application of this 15% infested plant threshold to broccoli and cauliflower decreased insecticide applications by 40% and 17%, respectively. Study of larval biology indicated that all of the lepidopterans preferentially fed on leaves; timing of the first insecticide application in broccoli and cauliflower to coincide with floret initiation decreased insecticide applications by 80% and 67%, respectively. Laboratory and field trials comparing DBM oviposition preference, larval survivability, and parasitism rates between cabbage, broccoli, and cauliflower are discussed. Knowledge of lepidopterous pest seasonality and biology, linked to careful timing of insecticide applications to coincide with threshold levels of pests, can take full advantage of natural enemies and reduce insecticide input in the vegetable brassicas of cabbage, broccoli, and cauliflower with no decrease in crop quality.

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Ochieng'-Odero, James Patrick. "Aspects of the life cycle, biological performance and quality of the black lyre leafroller 'Cnephasia' jactatana (Walker)." Thesis, University of Auckland, 1988. http://hdl.handle.net/2292/2480.

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The thesis answers the general question of whether the quality of artificially reared insect species should be based on performance tests for intended use or whether quality should be based on a more holistic biological approach. The empirical research is carried out using the lepidopteran leafroller 'Cnephasia' jactatana (Walker). The thesis defines biological performance and quality in terms of the success of an insect population in survival and reproduction and regards the laboratory environment as an artificial habitat that insects must colonise in order to survive and reproduce. Changes in biological performance that occurred during 12 successive generations of laboratory rearing were due to selection, acclimatisation and domestication and not adaptation. Artificial colonisation is theoretically successful within a limited range of environmental factors. As the inherent genetic variability of the founder population determines the resilience of the population to changes in performance, the ranges of environmental factors during colonisation should be wide to 'capture' much of the variability. Using body size (weight) as an aspect of overall quality, the thesis presents evidence that the final instar larva of C. jactatana has a threshold mechanism (larval critical weight, LCW) that determines pupal and adult size. There is a proportionate decrease in weight from the maximum weight that a larva attains in the final instar (LMW) to pupa ( described as constant DP ) and to adult (DA). There is a direct relation between the latent feeding period (period between attaining an LCW and LMW), LMW, pupal and adult size, and the reproductive performance (fecundity ). Within the experimental conditions diet quality, temperature, photoperiod and artificial selection had no effect on the larval critical weight, DP or DA, the larval threshold mechanism in C. jactatana is probably a mechanical trigger that initiates pupation. Diet quality, temperature and thermophotoperiods affected pupal size, adult size and reproductive performance. Photoperiod had no significant effects on size and reproductive performance. Positive assortative selections for slow development and low pupal weight significantly decreased pupal and adult size, and reproductive performance. Selection for fast development and heavy pupal weight for three generations had no significant effect on size or reproductive performance. Larval critical weight is demonstrated as useful to define quality indices and predict the performance of laboratory reared insects. The general conclusion of the thesis is that insect quality should be defined more in terms of the success in survival and colonising ability rather than solely on the success for 'intended role' or 'fitness for use'.

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Paulin, M. G. (Michael Geoffrey). "A mathematical and comparative study on cerebellar control of vestibular reflexes." Thesis, University of Auckland, 1985. http://hdl.handle.net/2292/2041.

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The first aim of this thesis is an introduction to some basic aspects of multivariate control theory which are relevant to the question of how the brain controls movements. A regulator is a device which forces a system to follow a specified trajectory in the presence of perturbations which might cause it to diverge from that trajectory. Regulation involves constructing an additional control input which depends upon the difference between the actual system state and the desired state. This requires the construction of a state estimate from raw data about system input and output. For effective state estimation, the sensor input gain to the state estimator needs to be time-varying. Under certain assumptions, the appropriate input gain can be specified analytically. The feedback regulation signal can then be constructed as a function of the state estimate. For effective regulation, the gain of the feedback function has to vary during maneuvers. Under certain assumptions an appropriate feedback gain can be specified analytically. The state observer input gain equations have a simple relationship to the feedback gain equations, so that gain specification is essentially the same task in each case. Cerebellar research has been dominated for the past 25 years by the theories of James Albus and David Marr. These mathematicians proposed similar models in which certain synapses in the cerebellar cortex are continuously modified by experience in such a way that movements which are consistently repeated under a given set of circumstances come to be performed automatically by the cerebellum. Much experimental work has focussed on the role of the vestibulo-cerebellum in fine control and learning of the vestibulo-ocular reflex. The state of the art along this line is formally described by Fujita's adaptive filter model of the cerebellar cortex. In chapter 4 it is shown that a basic feature of Fujita's model is inconsistent with available evidence. The 'Tensorial theory of brain function' is discussed in chapter 5. This is a novel theory of brain function which has been used in an attempt two explain cerebellar function. The attempt is a failure, based on sophistocated misconceptions and flawed by poor reasoning and clumsy analysis. The approach serves to confuse rather than clarify the question of cerebellar function. The final chapter of the first part of the thesis presents a basis for a new approach to cerebellar function based on the engineering theory of control of multivariate dynamical systems. It is proposed that the cerebellum is involved in movement regulation by controlling the gains of brainstem motor pathways, and in mapping the animal's environment by controlling the gains of sensory inputs to the midbrain. While learning undoubtedly does occur in the cerebellar cortex, this is not specifically a 'learning device', as commonly conceived. The second part of the thesis is concerned with the development and application of a method of system identification for characterising the dynamics of the vestibulo-ocular reflex and its components in an elasmobranch. The chosen method involves pulse-rate modulated bilateral electrical stimulation of the horizontal semicircular canal ampullary nerves. This produces a synthetic vestibulo-ocular reflex in a stationary preparation. The stimulus pattern is a pseudorandom binary sequence of pulse rates, so that cross-correlation of the stimulus pattern with the response signal gives a Unit Impulse Response dynamic signature for the system. Computer software for signal generation, recording, analysis and display was written by the author. The identification system was applied first to characterise the dynamics of the eye movement response to horizontal canal ampullary nerve stimulation, and compare this to the dynamics of the eye motor plant alone. The eye motor preparation acts as a first order low-pass filter with a time constant of about 0.2 seconds (16°C), while the ampullary preparation acts as a second order low-pass filter with a dominant time constant of about 0.75 seconds (16°C). Central pathways of the elasmobranch vestibulo-ocular reflex extend the time constant of the motor plant by a factor of 3-4, as in other animals. Eye movements predicted by fitted linear models accurately mimic eye movements recorded during experiments, suggesting both that central pathways of the reflex operate normally during this somewhat un-naturally evoked response and that the identification procedure is effective. Furthermore, combination of the ampullary nerve to eye movement transfer function obtained in this study, with head rotation to ampullary nerve transfer functions obtained by other workers, gives a consistent picture of elasmobranch vestibulo-ocular reflex function predicting compensatory eye movements in the band 0.2 - 4.0 Hz., and perhaps higher. The identification method has also been applied to produce models of vestibulocerebellar Purkinje cell dynamics during electrically evoked vestibular eye movements. Linear identification gives a poor characterisation of Purkinje cell activity during the high frequency vestibulo-ocular reflex. This is incompatible with linear phase-compensator models of the cerebellar cortex, but consistent with the reflex gain modulation theory of cerebellar function advocated in the first part of the thesis.

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Millar, Craig D. (Craig Donald). "A molecular and evolutionary study of skua breeding systems." Thesis, University of Auckland, 1993. http://hdl.handle.net/2292/2269.

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The skua (Family Stercorariidae) are a group of large, gull-like, predatory seabirds. Two skua species are found in the Antarctic region; the south polar skua (Catharacta maccormicki) and the brown skua (C. lonnbergi). The breeding distribution of the former, is restricted to the Antarctic continent and nearby islands, while the latter has a circumpolar distribution which extends northward from the Antarctic Peninsula and includes many of the Southern Ocean islands. The south polar skua is strictly monogamous, while in contrast, a number of populations of brown skua are comprised in part of communally breeding groups. The brown skua represents the only known example of a communally breeding seabird. In every skua species, breeding females are on average larger and heavier than males. However, in most skua species this dimorphism is relatively small and is of only limited use in sexing individuals. The discovery of sex-specific fragments in the DNA fingerprints of the south polar skua is reported. The multilocus probe pV47-2 hybridised to Hae III restriction fragments which were present exclusively in females and therefore presumably W-linked. The presence of these sex-specific fragments were used to identify female adults and chicks. In addition, the use of these fragments as potentially informative maternal markers is discussed. The parentage of the 13 families from two populations from Ross Island, Antarctica, determined by DNA fingerprinting, revealed a single instance of extra-pair paternity and a single instance of a chick which was parented by neither resident adult. The most likely explanation for the latter is the 'adoption' of a chick from a neighbouring territory. Similarly, DNA fingerprinting was used to assign the sex of individuals of brown skua from a population which breeds on the Chatham Islands, New Zealand. A large proportion of the Chatham Islands population breed in communal groups. Each communal group was shown to be comprised of a single female and two or more males. Consequently, the overall sex ratio amongst breeding birds was biased, with almost twice the number of males as females. In contrast the sex ratio amongst fledgling chicks did not differ significantly from 1:1. The patterns of reproductive success in breeding pairs and communal groups of the brown skua from the Chatham Islands population were determined using multilocus DNA fingerprinting. Sixteen breeding groups were examined, the parentage of 45 chicks produced over three breeding seasons was established using the probes 33.15 and 33.6. No evidence was found of either extra-pair paternity or extra-group fertilisation and there was no evidence of egg dumping by females in any breeding group. These results suggest that long-term banding records for breeding pairs and communal groups accurately reflect the overall reproductive success of these individual groups. In addition, preliminary band sharing analysis indicated that adult members of communal groups were not closely related. These findings are also supported by banding records and are in contrast to the findings of the majority of communally breeding species studied. In the 10 communally breeding groups examined, multiple paternity within a clutch was recorded on two of the 12 occasions in which two chicks were reared. Furthermore, analysis of parentage of the chicks belonging to communal groups in which the adults had remained unchanged for two or more seasons showed that some males had variable reproductive success in different seasons. These records suggest that estimates of reproductive success of individuals based on a single season's data can be misleading. Should temporal changes in paternity (and/or maternity) be shown to be common phenomena in other species, this would have major implications for the interpretation of many parentage studies. The explanation of altruistic behaviour is one of the central issues in contemporary evolutionary theory and behavioural ecology. One of the best known examples of apparent altruism is the helping behaviour which occurs in communal breeding groups such as those found in the brown skua. Within these groups individuals often help to raise offspring which are not their own. This behaviour is an apparent enigma in a world in which organisms are assumed to act in a selfish manner. Consequently, this behaviour has become a focal example at the centre of much evolutionary debate. A variety of theories have been suggested to explain helping behaviour, the most recent is that helping is an unselected consequence of the evolution of communal breeding. This hypothesis is discussed in relation to the recent literature and it is concluded that it does little to advance the current debate. An alternative theoretical approach to helping behaviour is outlined. In conclusion the general findings from the investigation of communal breeding in the brown skua are summarised and these findings are discussed. Finally, possible areas of future research are outlined.
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Stevens, Peter M. (Peter Michael). "Host races and cryptic species in marine symbionts." Thesis, University of Auckland, 1990. http://hdl.handle.net/2292/2321.

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The Pinnotheridae is a family of decapod crustaceans comprising more than 120 mostly microphagous and commensal species. As symbionts of a variety of aquatic invertebrates, pinnotherids typically live in an intimate association with their host depending on it for an almost lifelong source of nourishment and shelter, together with a site for mating. The New Zealand pinnotherid fauna was thought to comprise only one species, Pinnotheres novaezelandiae Filhol, associated with a multitude of hosts. Recently, however, a separate species, P. atrinicola Page, has been described which is regarded as being host specific to the horse mussel Atrina zelandica Gray. In this context, the relationship between pea crabs and their hosts is of special interest, and is the focus of this thesis. An investigation into the population dynamics of the symbiotic relationship between P novaezelandiae and its host, the green-lip mussel Perna canaliculus, at Westmere Reef, Auckland between May 1986 and July 1988 is reported. Ovigerous females and Stage I males and females were found throughout the sampling period, indicating that reproduction is continuous in this species. The developmental composition of the pea crab population reveals that soft-shelled males, usually regarded as an anomalous instar, formed a significant component of the pea crab population at all times. It is suggested that these individuals represent a distinct facies, analogous to the Stage II female instar. The presence of a pea crab was found to have a highly significant detrimental effect on mussel condition. Analysis of the distribution of pea crabs among the mussel population indicates mature crabs display a repulsed distribution favouring to live a solitary existence, whereas younger (pre-hard and Stage I) crabs showed a random distribution in broad agreement with a theoretical Poisson distribution. The biological status of the two described taxa was investigated by a survey of electrophoretically detectable genetic variation of populations from throughout the North Island of New Zealand. Pea crabs from 18 host populations from nine geographically disparate localities were subjected to cellulose acetate and poly-acrylamide electrophoresis. Forty-one enzyme systems were screened for polymorphism. Clearly resolved enzyme phenotypes were obtained at 23 presumptive loci, of which l5 exhibited polymorphism. An analysis of electromorph frequency data revealed that both taxa are highly genetically structured and typified by high levels of polymorphism and heterozygosity; results atypical of brachyuran crabs. P- atrinicola was found to exhibit strong patterns of geographic differentiation and clinal variation in electromorph frequency. Of particular significance is the pattern of genetic differentiation observed among populations of p. novaezelandiae. Hierarchical F-statistics indicated that the preponderance of inter-population differentiation can be attributed to differences in electromorph frequency among host-associated populations of P. novaezelandiae within a sampling locality. Geographic differentiation was a comparatively insignificant factor in the structuring of the sampled P. novaezelandiae populations. Individuals belonging to two genetically very distinct units were found within a newly recorded host species, Mactra ovata ovata Gray at Green and Wood Bays, Manukau Harbour. Hardy-Weinberg analyses indicate the host-associated populations of P. novaezelandiae exhibit such a pronounced pattern of homozygote excess and disturbance from genetic equilibrium in sympatry that it is unreasonable to consider them as a single panmictic population. It is concluded that significant biological discontinuities based on host origin exist within the currently recognised taxon. Such a conclusion is supported by data presented on qualitative differences in host recognition observed between different host-associated populations of P. novaezelandiae. Conservatively these discontinuities indicate host race development, although a viable alternate hypothesis would be the presence of cryptic, host-specific biological species within P. novaezelandiae. Hostrace development as found here is a well recognised phenomenon in insect-host and parasitoid-host relationships, although little studied in marine symbiotic relationships. Such a phenomenon has important implications for ecological, behavioural and physiological studies on marine symbionts in general.

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Francis, Malcolm 1954. "Population dynamics of juvenile snapper (Pagrus auratus) in the Hauraki Gulf." Thesis, University of Auckland, 1992. http://hdl.handle.net/2292/1976.

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The population dynamics of juvenile snapper, Pagrus auratus, were investigated in the Hauraki Gulf, north-eastern New Zealand, between 1982 and 1990. Attention focused on age and growth, temporal and spatial variation in abundance, and recruitment. Daily increment formation was validated in the sagittae of snapper up to about 160 days old. Increment width varied with time of year, and snapper age, and increments were not resolvable with a light microscope during winter. Increment counts inside a prominent metamorphic mark showed that larval duration was 18-32 days, and was inversely related to water temperature. Spawning dates were back-calculated from increment counts in settled juveniles, and ranged from September to March with a peak in November-January. The onset of spawning was temperature dependent. Fast-growing snapper had smaller sagittae than slow-growing snapper, indicating an uncoupling of otolith and somatic growth. Snapper gonads differentiated first as ovaries during the second year of life, and then some juveniles changed sex to become males during their third year. Sex change occurred before maturity, so snapper are functionally gonochoristic. Growth was slow during the larval phase, but increased rapidly after metamorphosis to about 0.6-0.9 mm.day-1. From the first winter, growth followed a well-defined annual cycle, with little or no growth during winter, and linear growth of 0.16-0.43 mm.day-1 during spring-autumn for 0+/1+ and 1+/2+ snapper. Snapper grew faster at higher temperatures. Trawl catch rates were affected by numerous gear and environmental factors, but probably provided reasonable estimates of snapper relative abundance. Recommendations are made for improving snapper trawl survey procedures. There was a strong annual abundance cycle in the Kawau region, peaking in spring, and declining to a minimum in winter. Snapper were patchily distributed at a spatial scale of 1-2 km, probably because of preference for specific micro-habitats. Year class strength of 1+ snapper varied 17-fold over seven years, and was strongly positively correlated with autumn sea surface temperature during the 0+ year. The strengths of the 1991 and 1992 year classes are predicted to be below average, and extremely weak, respectively.

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Page, Roderic D. M. (Roderic Dugald Morton). "Panbiogeography: a cladistic approach." Thesis, University of Auckland, 1990. http://hdl.handle.net/2292/1999.

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This thesis develops a quantitative cladistic approach to panbiogeography. Algorithms for constructing and comparing area cladograms are developed and implemented in a computer program. Examples of the use of this software are described. The principle results of this thesis are: (1) The description of algorithms for implementing Nelson and Platnick's (1981) methods for constructing area cladograms. These algorithms have been incorporated into a computer program. (2) Zandee and Roos' (1987) methods based on "component-compatibility" are shown to be flawed. (3) Recent criticisms of Nelson and Platnick's methods by E. O. Wiley are rebutted. (4) A quantitative reanalysis of Hafner and Nadler's (1988) allozyme data for gophers and their parasitic lice illustrates the utility of information on timing of speciation events in interpreting apparent incongruence between host and parasite cladograms. In addition the thesis contains a survey of some current themes in biogeography, a reply to criticisms of my earlier work on track analysis, and an application of bootstrap and consensus methods to place confidence limits on estimates of cladograms.

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Pankhurst, Patricia Melva. "Growth, development and visual ontogeny of two temperate reef teleosts Pagrus auratus, (Sparidae) and Forsterygion varium, (Tripterygiidae)." Thesis, University of Auckland, 1991. http://hdl.handle.net/2292/2000.

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Growth, development and behaviour were examined in artificially reared larval Pagrus auratus and Forsterygion varium, from the time of hatching. Yolk-sac larval P.auratus hatched at a small size (2.00mm SL), without functional eyes, mouth or digestive tract, and for three days spent long periods at rest. Growth was initially rapid but slowed by 3 days as yolk reserves neared depletion. By days 4-5, the mouth had opened, eyes were functional, yolk was depleted, and a rudimentary gut had formed. Larvae were now able to maintain a horizontal swimming mode and were actively searching for and attacking prey. First feeding was observed in some larvae. Growth was retarded during the transition from endogenous to exogenous nutrition and then increased as feeding proficiency improved. Yolk-sac F.varium hatched at a larger size (4.78mm SL), with functional eyes and jaws. Larvae were able to maintain a horizontal swimming mode from hatching. First feeding was observed from the first day after hatching. F.varium larvae grew steadily from the time of hatching. Ocular morphology was examined in larval, juvenile and adult P.auratus and F.varium. There was a 96 fold increase in eye size, from 0.23mm diameter in a 4 day old larval P.auratus (3.4mm SL) to a maximum diameter of 22mm in an adult of 333mm body length. F.varium displayed a 26 fold increase in eye size, from 0.28mm diameter in the smallest larva (5.00mm SL) to a maximum eye diameter of 7.2mm in a 11gmm long adult. Larval fish had pure cone retinae, however putative rod precursor cells were present from hatching in F.varium and from 18 days in P.auratus. Juvenile and adult fish had duplex retinae with cones arranged in a square mosaic in which 4 twin cones surround a central single cone. Hypertrophy of cone ellipsoids with increasing eye size, resulted in maintenance of a closely packed array in fishes of all sizes. The appearance of retinomotor movements was coincident with the development of a duplex retina in both species. Theoretical spatial acuity (calculated as a function of cone spacing and focal length of the lens) was poor in the smallest larval fish (2° 1' and 1° 8' minimum separable angle in 4 and 1 day old P.auratus and F.varium respectively) but improved to asymptotic values in adults (3'- 4', and 9' in P.auratus and F.varium respectively). Behavioural acuity (determined using the optokinetic response) of 4 day old larval P.auratus (37° 30') and 1 day old F.varium (29°) was very much lower than histological estimates. Behavioural acuity improved to 8° 8' in 16 day old P.auratus and 4° 18' in 14 day old F.varium, but did not attain theoretical estimates for fish of that size (55' and 54'). A rudimentary retractor lentis muscle was first apparent in larval fish 1 week after hatching, and was coincident with the formation of a posterior lental space. Presumably larval fish eyes were incapable of accomodative lens movements until this time. A relative measure of Matthiessen's ratio (distance from lens centre to boundary of the pigmented retinal epithelium/lens radius) measured histologically, decreased from 4.2 and 2.7 in 3 day old P.auratus and newly hatched F.varium, to 2.2 and 2.3 in larvae 22 and 16 days of age respectively. This suggests that growth of the retina and lens were not symmetrical in the eyes of very small larval fish. If Matthiessen's ratio holds for little eyes, then they will initially be strongly myopic. This may account in part for the mismatch between behavioural and theoretical acuity. Perceptive distances of first feeding larval P.auratus and F.varium, estimated for prey items equal in dimensions to maximum jaw widths, were very small (0.2mm and 0.4mm for prey 0.15mm and 0.2mm in size respectively), but increased with increasing body size to 2.1mm and 4.0mm for prey 0.3mm in size, at 16 and 14 days of age respectively. These data have implications for larval feeding in the wild.

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Brown, Samuel David James. "Molecular systematics and colour variation of Carpophilus species (Coleoptera: Nitidulidae) of the South Pacific." Diss., Lincoln University, 2009. http://hdl.handle.net/10182/1430.

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The sap beetle genus Carpophilus Stephens (Coleoptera: Nitidulidae) is a large genus consisting of over 200 species and are found worldwide. Several species are important pests of crops and stored products, and are frequently intercepted as part of biosecurity operations. The genus is poorly known taxonomically, and there are several species groups that are challenging to identify by morphological methods. In particular, two species found across the Pacific, C. maculatus Murray and C. oculatus Murray are frequently confused with each other. These two species are similar in size and colour, but differ primarily by the shape of the colour pattern on their elytra. However, this colour pattern is highly variable within both species, leading to ambiguity in the indentification of these species. Within C. oculatus, three subspecies have been described based on differences in the male genitalia and pronotal punctation: C. o. oculatus and C. o. gilloglyi Dobson are distributed widely across the Pacific, while C. o. cheesmani Dobson is known only from Vanuatu. A search of literature records and specimen collections revealed 32 species of Carpophilus recorded from the Pacific region. In addition there remain several unidentified specimens representing at least four species, two of which will be described subsequent to this research. A number of species recorded in the literature may have been misidentified, and these require further field collections and inspection of museum specimens to confirm their presence in the Pacific. To test the validity of the subspecies of C. oculatus, and its distinctiveness from C. maculatus, a phylogeny of available specimens of Carpophilus was inferred from one mitochondrial gene (cytochrome c oxidase subunit I (COI)), and two nuclear genes (28S ribsomal RNA (28S) and the internal transcribed spacer 2 (ITS2)). These data show large genetic distances between the three subspecies of C. oculatus of 7-12%. Given these distances are similar to those between other species in the genus, this indicates these subspecies may be elevated to full species. The data also consistently support a monophyletic relationship between C. o. oculatus and C. o. gilloglyi. Nuclear genes also support C. o. cheesmani as part of a clade with the other subspecies, but these relationships are unresolved in COI. Carpophilus maculatus was not supported as being the sister taxon of the C. o. oculatus and C. o. gilloglyi clade. Other relationships within Carpophilus were unresolved, possibly due to a combination of incomplete taxon sampling, and saturation of substitutions within the COI gene. Phylogeographic analysis of specimens collected from several localities within the range of C. oculatus showed that, with only one exception, there were no shared haplotypes between archipelagoes. This result suggests it may be possible to determine the provenence of intercepted specimens, providing further information regarding potential invasion pathways. A degree of geographic structuring was also present within C. o. gilloglyi, being separated into a western clade found in Fiji and Rotuma and an eastern clade distributed from the Kermadec Islands and Tonga to French Polynesia. This separation was most profound in COI data, with a mean pairwise distance between the clades of 7%. ITS2 data also demonstrates a degree of differentiation between the two clades, based on differences in the insertions and deletions between the clades. The variability in the shape and colour of the elytral pattern of C. oculatus was also investigated. Colour was quantified using a method based on Red-Green-Blue (RGB) colour values derived from digital photographs, while an outline analysis of the elytral pattern was conducted using elliptic Fourier analysis (EFA). Principal Components Analysis of the RGB values and EFA coefficients showed no clear separation between subspecies, nor were any trends correlated with host fruit or collection localities. Variation at all levels and all measures studied in this thesis show that this geographic region and this genus of beetles offer intruiging insights into speciation, biogeography and biological invasions. There is much scope for further research on the causes and consequences of this variation and the lives of these interesting insects.

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12

Middleton, Danielle Mary Rose Lea. "The prevalence of Salmonella and the spatial distribution of its serovars amongst New Zealand's native lizards : a thesis presented in partial fulfillment of the requirements for the degree of Master of Science in Zoology at Massey University, Palmerston North, New Zealand." Massey University, 2008. http://hdl.handle.net/10179/906.

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This thesis considers the prevalence and spatial distribution of Salmonella serovars amongst wild endemic lizards on offshore islands around the coast of New Zealand. The mean test prevalence of faecal excretion of Salmonella was 4.7%. Skinks (Scincidae) were more likely (8.5%) to be carriers of Salmonella than geckos (1.6%). Each island was host to between one and three Salmonella serovars that were not found on any other islands in this study. Two exceptions were Salmonella Bousso and Salmonella Mana which were found on two islands within the same geographical area. Based on the findings of this study, different islands are likely to be hosts to different Salmonella serovars which could have implications for future translocations of native lizards. I also assessed the prevalence and spatial distribution of faecal excretion of Salmonella, Aeromonas and Hafnia alvei within Mana Island. The prevalence of Salmonella on Mana Island was estimated at 5.8%. Salmonella was found predominantly in skinks (10.0%) and less often in geckos (4.1%). H. alvei was found at a prevalence of 1.9%. No Aeromonas species were cultured from any of the cloacal swabs, suggesting that the 95% confidence interval for the true prevalence is 0-3%. Each site sampled in this study was host to one or more unique serovar of Salmonella not found at any of the other sites. The results of this study indicate that Salmonella serovars may become established within populations of lizards and is not spread between them. This may be due to a lack of dispersal of lizards between sites, raising important considerations for the translocation of native lizards. I investigated the prevalence of faecal excretion of Salmonella, H. alvei and Aeromonas by New Zealand native lizards from two captive populations. The mean prevalence of faecal excretion of Salmonella in the captive lizards sampled was 11.5%. There was a higher prevalence of Salmonella within captive population A (22.0%) than in population B (3.6%). No Aeromonas was cultured from any of the lizards. H. alvei was found at a prevalence of 5.2%. The prevalence of Salmonella and H. alvei was significantly higher in captive lizards than in wild populations. Captive lizards may, therefore, not be appropriate founders for new populations of wild lizards. Finally I assessed the different efficiencies of two media and two temperatures in isolating six Salmonella serovars from a reptilian source. All serovars grew equally well at 37°C and 27°C. For most serovars XLD agar was the more successful media than MacConkey agar but the success of different culture media depended on the serovar being cultured. Because lizards are frequently host to a wide range of Salmonella serovars, screening samples using multiple microbiological methods is likely to give the best chance of isolating all Salmonella serovars present.

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13

Campbell, Kirsten L. "A study of home ranges, movements, diet and habitat use of kereru (Hemiphaga novaeseelandiae) in the southeastern sector of Banks Peninsula, New Zealand." Master's thesis, Lincoln University. Bio-Protection and Ecology Division, 2006. http://theses.lincoln.ac.nz/public/adt-NZLIU20080317.131118/.

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The present study is part of the Kaupapa Kereru Programme. The main aim of the programme is to increase the numbers and range of kereru (Hemiphaga novaeseelandiae) on Banks Peninsula. Home ranges, movements, diet and habitat use of 15 kereru captured in Hinewai Reserve, Banks Peninsula, were investigated from February 2005 to February 2006. Hinewai Reserve is the largest tract of regenerating native forest in a highly modified urban-rural landscape. Phenology of 11 plant species predicted to be key kereru foods, was studied to determine the pattern of food availability in Hinewai Reserve. Twelve radio-tagged kereru resided in the Hinewai Reserve study site (Otanerito Valley and Sleepy Bay) and three resided in Akaroa. Ripe fruit was available from January to August; the height of the fruiting season was in autumn. The bulk of new leaf growth occurred in spring and early summer although new leaves were available on broom and tree lucerne year round. Peak flowering occurred in spring. Kereru in Akaroa ate a total of 21 plant species; six of these species were native and 15 introduced. Kereru in the Hinewai Reserve study site ate a total of 26 plant species; 20 of these species were native and six introduced. Fruit was preferred when readily available. Native fruit appeared to be preferred over fruit of introduced species in Akaroa, where both types were available. New foliage of introduced legumes and deciduous species appeared to be preferred over new foliage of native species at both sites during winter and spring. These species were important food sources prior to the breeding season and may be selected specifically for their nitrogen and protein content. Food is currently not a limiting factor for kereru survival or reproductive success. Considerable variation in the use and preference of vegetation types of individual kereru made it difficult to identify trends in habitat selection. Use and preference for many vegetation types was seasonal; this was certainly because of the availability of food species included in or close to these vegetation types. Overall, native vegetation communities were used more than communities dominated by introduced species and forest communities were used more than non-forest communities. Kanuka (Kunzea ericoides) was used most often for non-feeding activities and 67% of observed nests were built in kanuka. Annual home ranges and core areas in the Hinewai Reserve study site (mean of 15.9 and 2 ha respectively) were significantly larger than those found in Lyttelton Harbour, Banks Peninsula in previous research (mean of 8 and 0.08 ha respectively). Home ranges were larger when fruit was eaten, than when no fruit was eaten indicating that kereru are more sedentary when feeding on foliage. Kereru from the Hinewai Reserve study site made no excursions >5 km and no daily movements >2 km. Kereru from Akaroa and Sleepy Bay travelled into Otanerito Valley to feed on horopito in autumn, indicating that there may have been a lack of fruit in their local areas during autumn. No kereru in Otanerito Valley travelled outside of the valley. The distribution of high quality food sources is likely to have caused the observed differences in home range and core area size between localities. Kereru in Lyttelton Harbour may have been restricted to small patches of high quality resources in a study area consisting largely of unsuitable habitat. In Hinewai Reserve, high quality resources were spread over larger areas and were more uniformly distributed. The density of kereru was unknown at both study sites, and this confounded assessment of habitat quality. However, it is likely that the Hinewai Reserve study site would support a higher number of kereru. The main factor limiting population growth in the present study was failure of nests at the egg and chick stage. The fledge rate was 17%. Two of fifteen adult kereru died. Control of predators should be the first aspect of management that is focused on, and will almost certainly increase reproductive success of kereru and loss of breeding adults. As the population of kereru on Banks Peninsula increases due to predator control in existing kereru habitat, food may become a limiting factor. Habitat can be improved for kereru by planting a diverse range of plant species that provide food year-round. Native fruiting species are greatly recommended for habitat enhancement and should be selected so that fruit is available for as much of the year as possible. Native and introduced legumes should also be made available as foods for winter and spring. As most land on Banks Peninsula is privately owned, co-operation and enthusiasm of the community is critical for successful management. Information and support needs to be given to landowners wishing to enhance their properties for kereru.

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14

Hughey, Kenneth F. D. "Hydrological factors influencing the ecology of riverbed breeding birds on the plains' reaches of Canterbury's braided rivers." Lincoln College, University of Canterbury, 1985. http://hdl.handle.net/10182/1639.

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The wide, unstable, braided riverbeds of the eastern South Island, New Zealand, have been inhabited by a diverse avifauna. Several species including the wrybill breed only on these rivers. Use is restricted mainly to the breeding season from September to December, so this was the critical study period. Previous, behaviourally oriented studies have occurred mainly in the high country catchments where habitat modification is slight. However, substantial bird numbers also occur on lowland riverbeds. These areas are subject to existing or planned water developments which may have negative impacts on the conservation of these habitats and bird species. The principal goal of this study was to add to the information necessary to conserve lowland riverbed habitat within multiple use planning strategies. Specific objectives associated with assessing breeding and feeding requirements were therefore hydrologically oriented. Study areas were chosen on the lower Rakaia and lower Ashley rivers. Both are braided but have markedly different flow regimes. The Rakaia is snowfed and has peak flows occurring during the breeding season. The Ashley is primarily rainfed and has a declining breeding season flow regime. Wrybills, black-fronted terns, banded dotterels, South Island pied oystercatchers, and pied stilts breed in these areas. The first two of these were selected as indicator species. It was assumed that because of their restricted habitat needs, flow requirements recommended to meet their needs would also meet those of most other species. Banded dotterels were also studied because of their close taxonomic relationship and overlapping distribution with wrybills. South Island pied oystercatchers and pied stilts were chosen to check the validity of the approach. Breeding, nest site requirements, microhabitat preferences for foraging, diets, home ranges and food supply were studied. Wrybill time-budgets were examined, and the incremental approach to impact assessment was applied to wrybill foraging needs. Breeding success for all species was dependent on the flow regime. In 1982 wrybill fledging success was moderate on the Rakaia, whereas in 1983 it was very low. Conversely, in both years fledging success was very high on the Ashley. This variability resulted from serious flooding on the Rakaia in 1983 which effected all species. Wrybills have nest site characteristics most closely approximating a habitat specialist, while the other species should be considered habitat generalists. Nests are generally close to water, near minor braids, and on non-vegetated shingle substrates. On average there is a higher chance of nests being flooded on the Rakaia than on the Ashley where predation is more likely to reduce nesting success. Vegetation encroachment threatens nest site provision and floods are presently the only natural regular of exotic plants such as lupin. Banded dotterel home ranges were significantly smaller than wrybills, and on an intra-specific basis were smaller on the Ashley. A correlation existed between home range size and habitat quality, so that small wrybill home ranges were dominated by the occurrence of productive minor braids, and larger ones by less productive major channels. Time-budgets provided further insights into the influence of hydrological factors on wrybill ecology. Wrybill time-budgets appear to be inflexible because a high proportion of time is devoted to foraging, with relatively little time available for other activities. Resource depression on the Rakaia in 1983 lessened the chances for wrybills to breed successfully because sufficient food could not be gathered to provide for breeding energy needs. This did not occur on the Ashley River where flows were generally more stable. From a management viewpoint, development strategies which lead to greater flow fluctuations will have a detrimental impact on wrybills. The foraging patterns for all species except black-fronted terns were examined. There was a general preference for aquatic habitats, particularly those associated with minor braids and disconnected pools. Depth and substrate use were studied in detail for wrybills and banded dotterels. Wrybills displayed consistent use patterns between rivers, which reflected specialisation in habitat use. Banded dotterel habitat use varied considerably. Diet was studied by faecal analysis. Both wrybills and banded dotterels fed on invertebrates of aquatic and terrestrial origin. For wrybills it was noticeable that Ephemeroptera larvae did not dominate the diet as had previously been reported for high country catchments. Coleoptera, Hemiptera, and Ephemeroptera were important on the Rakaia with Trichoptera replacing Ephemeroptera larvae on the Ashley. Banded dotterels were more reliant on Coleoptera and Hemiptera on both rivers. Pitfall trapping results showed that terrestrial invertebrate availability was dependent on the proximity of water. Fewer floods on the Ashley led to a more consistent food supply on that river. This helps explain the greater bird density on this river. Severe flooding in 1983 appeared to seriously depress aquatic invertebrate densities on the Rakaia. The incremental approach to impact assessment was applied to wrybill foraging requirements. Depth, substrate, and water velocity preferences were included within a weighted usable area model already developed for fisheries use on the Rakaia River. Over the range of median to low flows studied, weighted usable area increased with declining discharge. A simplified usable width approach was applied to a highly braided section of the Ashley River. Here, usable width declined with falling discharges. This inter-basin difference could be explained with reference to the braiding pattern of each river. The main study objectives were achieved, but the indicator species management approach was of limited value in areas other than nest site requirements. Pied stilts and South Island pied oystercatchers fed at greater depths than wrybills, and often used different microhabitats. However, for foraging, wrybills need appeared adequate indicators of banded dotterel requirements.

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15

Barron, M. C. "Population ecology of the red admiral butterfly (Bassaris gonerilla) and the effects of non-target parasitism by Pteromalus puparum." Lincoln University, 2004. http://hdl.handle.net/10182/1763.

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There is anecdotal evidence that populations of the New Zealand endemic red admiral butterfly Bassaris gonerilla (F.) have declined since the early 1900s. This decline has been associated with the introduction of the generalist pupal parasitoids Pteromalus puparum (L.) and Echthromorpha intricatoria (F.). The former was deliberately introduced for the biological control of the cabbage white butterfly (Pieris rapae (L.)); the latter is an adventitious arrival from Australia. The objective of this thesis was to quantify, using population models, the effect that P. puparum is having on B. gonerilla abundance. Population monitoring and a phenology model (based on temperature-related development rates) indicated that B. gonerilla has two full generations and one partial generation per summer in the Banks Peninsula region of New Zealand. B. gonerilla abundance was greatly reduced in drought summers, which was probably due to the negative effects of drought on the quality and quantity of the larval host plant Urtica ferox Forst. A life table study showed that egg parasitism by the unidentified scelionid Telenomus sp. was the largest mortality factor for the pre-imaginal stages of B. gonerilla, followed by "disappearance" mortality (predation and dispersal) in the larval stages. Pupal mortality due to P. puparum was lower compared with that caused by E. intricatoria, with 1-19% and 20-30% of pupae being parasitised by P. puparum and E. intricatoria, respectively. Collection of B. gonerilla pupae from the Christchurch, Dunedin and Wellington areas confirmed higher rates of percentage parasitism by E. intricatoria. B. gonerilla collected from the Banks Peninsula had a 50: 50 sex ratio and lifetime fecundity was estimated in the laboratory as 312 eggs per female. There was no evidence of density-dependent parasitism of B. gonerilla pupae by P. puparum in the field, although there was a significant positive relationship between life table estimates of E. intricatoria parasitism and B. gonerilla pupal abundance. Larval dispersal from the host plant showed a positive relationship with larval instar but no relationship with larval density. Rates of change in B. gonerilla adult abundance between generations within a year showed evidence of density dependence, and this negative feedback was stronger in a drought year. A discrete-time model for B. gonerilla population dynamics was constructed which had two summer generations per year and a partial overwintering generation. The model showed that the presence of this overwintering generation provides a temporal refuge from high levels of E. intricatoria parasitism. Removal of parasitoid mortality from the model suggested that P. puparum was suppressing B. Gonerilla populations on the Banks Peninsula by 5% and E. intricatoria by 30%. An important assumption of the model was that parasitism rates were independent of B. gonerilla density. This assumption appears valid for P. puparum parasitism, but may not be valid for E. intricatoria; therefore the estimated suppression levels due to this adventive parasitoid should be viewed with some caution. It is too soon to generalise on what determines the magnitude of non-target effects by arthropod biocontrol agents, this being only the second study to quantify effects at a population level. However, in this case retrospective analysis has shown that the impact of non-target parasitism by P. puparum on B. gonerilla abundance has been small. There is anecdotal evidence that populations of the New Zealand endemic red admiral butterfly Bassaris gonerilla (F.) have declined since the early 1900s. This decline has been associated with the introduction of the generalist pupal parasitoids Pteromalus puparum (L.) and Echthromorpha intricatoria (F.). The former was deliberately introduced for the biological control of the cabbage white butterfly (Pieris rapae (L.)); the latter is an adventitious arrival from Australia. The objective of this thesis was to quantify, using population models, the effect that P. puparum is having on B. gonerilla abundance. Population monitoring and a phenology model (based on temperature-related development rates) indicated that B. gonerilla has two full generations and one partial generation per summer in the Banks Peninsula region of New Zealand. B. gonerilla abundance was greatly reduced in drought summers, which was probably due to the negative effects of drought on the quality and quantity of the larval host plant Urtica ferox Forst.. A life table study showed that egg parasitism by the unidentified scelionid Telenomus sp. was the largest mortality factor for the pre-imaginal stages of B. gonerilla, followed by "disappearance" mortality (predation and dispersal) in the larval stages. Pupal mortality due to P. puparum was lower compared with that caused by E. intricatoria, with 1-19% and 20-30% of pupae being parasitised by P. puparum and E. intricatoria, respectively. Collection of B. gonerilla pupae from the Christchurch, Dunedin and Wellington areas confirmed higher rates of percentage parasitism by E. intricatoria. B. gonerilla collected from the Banks Peninsula had a 50: 50 sex ratio and lifetime fecundity was estimated in the laboratory as 312 eggs per female. There was no evidence of density-dependent parasitism of B. gonerilla pupae by P. puparum in the field, although there was a significant positive relationship between life table estimates of E. intricatoria parasitism and B. gonerilla pupal abundance. Larval dispersal from the host plant showed a positive relationship with larval instar but no relationship with larval density. Rates of change in B. gonerilla adult abundance between generations within a year showed evidence of density dependence, and this negative feedback was stronger in a drought year. A discrete-time model for B. gonerilla population dynamics was constructed which had two summer generations per year and a partial overwintering generation. The model showed that the presence of this overwintering generation provides a temporal refuge from high levels of E. intricatoria parasitism. Removal of parasitoid mortality from the model suggested that P. puparum was suppressing B. Gonerilla populations on the Banks Peninsula by 5% and E. intricatoria by 30%. An important assumption of the model was that parasitism rates were independent of B. gonerilla density. This assumption appears valid for P. puparum parasitism, but may not be valid for E. intricatoria; therefore the estimated suppression levels due to this adventive parasitoid should be viewed with some caution. It is too soon to generalise on what determines the magnitude of non-target effects by arthropod biocontrol agents, this being only the second study to quantify effects at a population level. However, in this case retrospective analysis has shown that the impact of non-target parasitism by P. puparum on B. gonerilla abundance has been small.

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16

Troup, Christina. "Foraging strategies of Southern Royal Albatrosses, Diomedea epomophora, Campbell Island during incubation." Lincoln University, 2004. http://hdl.handle.net/10182/1273.

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Among the species of Diomedea albatrosses, diverse foraging strategies during breeding have been described, indicating species differences in foraging ecology and behaviour. Foraging strategies of Southern Royal Albatrosses, Diomedea epomophora (SRA) breeding on Campbell Island were studied in January – early February 1999 during the latter half of incubation. Movements and activity of ten birds were monitored using satellite transmitters and wet-dry activity recorders. Three birds from a pilot tracking study in February 1997 were also included in some analyses. Foraging strategies, zones used, factors influencing the duration of foraging trips, and the influence of wind conditions were investigated. Foraging activity took place at sites with bathymetric characteristics associated with high productivity: outer shelf and shelf-break zones, with a concentration of activity on a shelf contour south of the Snares Islands. This is in contrast to Wandering (D. exulans) and Gibson’s (D. gibsoni) albatrosses, typically deep oceanic foragers, but is similar to Northern Royal Albatross (D. sanfordi). The maximum distance of foraging trips from the colony was 1250 kilometres (mean 584 +351(SD)). This was closer than for incubating Wandering and Gibson’s Albatrosses but more distant than for Northern Royal Albatross from the Otago Peninsula. The mean duration of 77 foraging trips from 52 nests was 10.11 days for females and 8.76 for males (ns). Foraging trips became shorter as incubation progressed. Foraging trips were shorter, but not significantly so, when the median wind speed throughout the foraging trip was higher. No significant relationship was found between bird mass and duration of foraging trips. The mean cumulative distance flown by the ten birds tracked in 1999 was 4262 km + 1318 (SD). Eight of the ten SRA employed a ‘commute, forage, commute’ foraging strategy, and the other two alternated short bouts of commuting and foraging. Commuting phases were characterised by rapid directional flight with a straight-line distance (range) of 180 km to 800 km between positions 24 hours apart. Foraging phases were characterised by a range of less than 180 km per 24 hour interval and frequent tight turns. Displacement rate between successive uplinks was significantly higher during commuting phases (28.6 kph + 1.93 SE) than foraging phases (15.1 kph + 1.4 SE). Wind strength and direction influenced the timing of the return commute to the colony. SRA covered greater distances at more favourable wind angles relative to flight track (broad reach and close reach) than in head, tail or direct side winds. Birds of low mass (< 8kg) made fewer landings in winds above 40 kph than in lighter winds, whereas heavier birds had a similar level of landing activity across all wind speed bands. One bird was delayed for several days by light winds, and another flew off course during strong winds. Two birds exploited the same window of wind conditions to return to the colony, each flying a similar course in both timing and route. These results define the foraging strategies of SRA during incubation, and demonstrate the influence of wind conditions and other factors on the overall duration of foraging trips and on the timing of commuting and foraging phases.

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17

Cripps, M. G. "Influence of natural enemies on Cirsium arvense — a biogeographic perspective." Lincoln University, 2009. http://hdl.handle.net/10182/1411.

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Cirsium arvense (L.) Scop. (Californian, Canada, or creeping thistle) is an exotic perennial herb indigenous to Eurasia that successfully established in New Zealand (NZ) approximately 130 years ago. Presently, C. arvense is considered one of the worst invasive weeds in NZ arable and pastoral productions systems. The mechanism most commonly invoked to explain the apparent increased vigour of introduced weeds is release from natural enemies. The enemy release hypothesis (ERH) predicts that plants in an introduced range should experience reduced herbivory, particularly from specialists, and that release from this natural enemy pressure facilitates increased plant performance in the introduced range. In 2007 broad surveys were carried out in NZ and central Europe in order to quantify and compare growth characteristics of C. arvense in its native vs. introduced range. Additionally, permanent field plots were established in NZ and Europe where natural enemies were excluded with the use of insecticide and fungicide applications, and compared with controls (ambient natural enemy pressure). The impact of the specialist leaf-feeding beetle, Cassida rubiginosa Müller, which was recently released in NZ as a biological control agent against thistles, was also assessed. From the field surveys, significantly more endophagous herbivory was present in the native range compared to the introduced range, as predicted by the ERH. Endophagous herbivory in NZ was solely from the capitulum-feeding weevil, Rhinocyllus conicus (Frölich), and was only found in the North Island surveys. No stem mining attack was found anywhere in NZ. The proportion of shoots attacked by the specialised rust pathogen, Puccinia punctiformis (Str.) Röhl., was similar in both the native and introduced ranges. Interestingly, this has casted doubt on the idea that stem-mining vectors, such as Ceratapion onopordi Kirby, are important for transmission of the rust pathogen. Contrary to the ERH, there were no significant difference in plant performance between the native and introduced ranges, or differences could be explained by simple climatic factors. Climate tended to be more favourable for growth of C. arvense in NZ. In the permanent field plots in the native range, population growth of C. arvense was significantly greater where natural enemies were excluded, suggesting that insect herbivores and pathogens might have a regulating influence on the population growth of this plant. Furthermore, the probability of shoots transitioning to the reproductive growth stage was enhanced when insect herbivores were excluded, indicating that natural enemies might influence plant development. The biological control agent C. rubiginosa reduced the growth of C. arvense, although the impact of this herbivore was minimal in comparison to interspecific plant competition. Thus, although there is reduced specialist natural enemy pressure in NZ, the growth of C. arvense is not significantly different from in its native range. Nevertheless, there is some evidence that natural enemies in the native range might have a regulating influence on the population dynamics of the plant, and that the specialist herbivore, C. rubiginosa, can impact the plant in certain conditions.

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18

Guichard, Sylvain. "Modelling the proximal source of intercepted exotic insects." Lincoln University, 2009. http://hdl.handle.net/10182/1472.

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Biological invasions are major threats to any nation’s economy and biodiversity. To detect new biological incursions of some species biosecurity agencies deploy pheromone sentinel traps for targeted species at high risk sites such as airports, seaports and transitional facilities. A good example is the gypsy moth surveillance program in New Zealand. Following the detection of an incursion by an unwanted organism, ground-based searches to locate the source can be very expensive, but are essential to identify the introduction pathway and to increase the chances of success eradicating the unwanted organism. In such circumstances, the possibility of better targeting the search for the source of the incursion using a modelling approach is worthy of investigation A stochastic mechanistic model to hindcast moth flight from a recapture location to the release location was developed based on insect behaviour in response to wind and pheromones. The model was composed of two main processes, 1) downwind dispersal, assumed to result from an appetitive behaviour, indicated by an analysis of a previous mark-release-recapture experiment on painted apple moth (Teia anartoides, Walker) and, 2) anemotaxic dispersal inspired by pheromone anemotaxis theory but up-scaled from a fine-scaled behaviour model to a 2 m scale. A genetic algorithm was used to fit some model parameters. A specialised fitness function was developed to allow the genetic algorithm to identify parameters that resulted in models that reflected both the spread and density patterns in the trapping data. The resulting function allowed the stochastic model results to be compared with the inherently stochastic trapping data. The resulting individual based model simulates the spatio-temporal dispersal pattern of painted apple moth recorded during a previous mark-release-recapture experiment. While the proposed model is shown to have limitations with respect to accuracy and precision it is also demonstrated to greatly improve biosecurity incursion response capability, by more efficient targeting of search effort for the proximal source of an incursion.

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19

Schmechel, Frances A. "Aspects of habitat selection, population dynamics, and breeding biology in the endangered Chatham Island oystercatcher (Haematopus chathamensis)." Lincoln University, 2001. http://hdl.handle.net/10182/1814.

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In the late 1980s the endangered Chatham Island oystercatcher (Haematopus chathamensis) (CIO) was estimated at less than 110 individuals. Endemic to the Chatham Islands, New Zealand, it was feared to be declining and, based on existing productivity estimates, in danger of extinction within 50-70 years. These declines were thought to be caused by numerous changes since the arrival of humans, including the introduction of several terrestrial predators, the establishment of marram grass (Ammophila arenaria) which changes dune profiles, and increased disturbance along the coastline. The New Zealand Department of Conservation has undertaken recovery planning and conservation management to increase CIO numbers since the late 1980s. Recovery planning raised some key research questions concerning the population dynamics, habitat selection, and breeding biology of Chatham Island oystercatcher (CIO), and the critical factors currently limiting the population. The objectives of this study were to collect and interpret data on: 1) population size, trends, and distribution across the Chathams, 2) basic breeding parameters, 3) recruitment and mortality rates, 4) habitat selection at the general, territorial and nest-site levels, 5) habitat factors that are correlated with territory quality, and 6) cues that elicit territorial behaviour in CIO.

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20

Wragg, Graham. "The comparative biology of Fluttering shearwater and Hutton's shearwater and their relationship to other shearwater species." Lincoln College, University of Canterbury, 1985. http://hdl.handle.net/10182/1635.

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The discovery and taxonomic history of fluttering shearwater (Puffinus gavia (Forster) and Hutton's shearwater (Puffinus huttoni Mathews) are reviewed. Taxonomic theory, where appropriate to this thesis, is discussed. The external morphology of P. gavia and P. huttoni is compared. No single external measurement or plumage character separates more than 60% of birds examined. The best system of identification is to compare the ratio of different body parts within an individual bird. The distribution of P. gavia and P. huttoni is compared. Hutton's shearwater feeds further out to sea and it is believed to be a migrant species wintering in north west Australian waters. The fluttering shearwater is believed to be a semi-migrant species with only the juveniles spending time in south east Australia. The red cell enzymes of P. gavia, P. huttoni and P. griseus are compared. There are differences in two esterase loci between gavia and huttoni, while P. griseus is more distantly related. Nei's genetic identity values are calculated. The systematic value of electrophoretic data is discussed. The relationship of an undescribed subfossil shearwater to P. gavia and P. huttoni is discussed. An outgroup analysis to other shearwater species is carried out according to phylogenetic (cladistic) theory. The subfossil shearwater is most closely related to the fluttering shearwater, and these two form a sister group to Hutton's shearwater. These three species are a sister group of P. opisthomelas. The relationship between the many P. assimilis subspecies, the black-backed Manx shearwaters, and the gavia, huttoni and opisthomelas group was not resolved. Puffinus nativitatis is more closely related to the Manx and the little shearwaters than to the P. griseus, P. tenuirostris group.

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21

Meynier, Laureline. "Feeding ecology of the New Zealand sea lion (Phocarctos hookeri) : a thesis presented in partial fulfilment of the requirements for the degree of Doctor Philosophy in Zoology at Massey University, Palmerston North, New Zealand." Massey University, 2009. http://hdl.handle.net/10179/901.

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The New Zealand (NZ) sea lion Phocarctos hookeri is the only pinniped endemic to NZ with a population of approximately 12,000 individuals. Its breeding range is currently restricted to NZ sub-Antarctic islands, and it has failed to recolonise its pristine distribution around the NZ main islands despite its protection since 1881. The current hypothesis is that the population growth of this pinniped is limited by the distribution of suitable prey on the Auckland Islands (50°30'S, 166°E) shelf, and by the direct and indirect pressure exerted by the arrow squid Nototodarus sloani fishery. However, this hypothesis has not been fully tested to date as there has been limited information on the diet of the NZ sea lion and their potential prey. The objective of this thesis is to analyse the diet of NZ sea lions over several years with particular emphasis on the most reproductively important segment of the population: lactating females. This thesis provides the first quantification by percentage mass of the diet of NZ sea lion using a combination of stomach content analysis, qualitative fatty acid (FA) analysis, and quantitative FA signature analysis (QFASA). Stomach contents and blubber FAs were analysed from 121 individuals incidentally caught (by-caught) in the southern arrow squid fishery from the years 1997 to 2006. The blubber FAs of 78 freeranging lactating females captured at Enderby Island, Auckland Islands, were also examined during January and February of 2000 to 2005. Data obtained from both stomach analysis and QFASA indicate that arrow squid, rattails Macrouridae, hoki Macruronus novaezelandiae and red cod Pseudophycis bachus are key prey species for NZ sea lions in the Auckland Islands region. Because these prey species live mostly at depths greater than 200 m, lactating females must undertake long foraging trips and dive regularly to greater depths than other sea lion species. Data from QFASA indicates that this foraging pattern is conducted over an extended period through the summer and autumn. The daily food requirement of a lactating female was estimated by a simple energetic model to be greater than 20% of its body mass. During years of low arrow squid recruitment such as 1999 and 2001, the amounts of squid required by the NZ sea lion population may have been similar to the amount harvested by the fishery, suggesting that resource competition is likely to occur between the arrow squid fishery and NZ sea lions in years of low squid abundance. Half of the fishing activity of the southern squid fishery occurs in the north of the Auckland Islands shelf where NZ sea lions forage, leading to incidental captures every year. This research emphasises that management of the NZ sea lion must not only consider the direct interactions with the arrow squid fishery, but also the likelihood of food resource competition between the fishery and NZ sea lions.

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Laubertie, Elsa. "The role of resource subsidies in enhancing biological control of aphids by hoverflies (Diptera: Syrphidae)." Diss., Lincoln University, 2007. http://hdl.handle.net/10182/984.

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In this thesis, experiments were conducted in the laboratory and the field to determine whether the provision of floral resources to hoverflies could enhance the biological control of aphids. The overall aim was to clarify hoverfly behaviour and ecology in an agroecosystem in order to understand the potential of these insects for biocontrol under a conservation biological control (CBC) regime. A preliminary experiment in New Zealand compared the effect of different coloured water-traps on catches of the hoverflies Melanostoma fasciatum (Macquart) and Melangyna novaezelandiae (Macquart). Significantly more individuals were caught in completely yellow traps than in traps with green outer walls and yellow inner walls or in completely green traps. This suggested that if a measure of hoverfly numbers relating to a particular distance along a transect is required, consideration should be given to the ability of hoverflies to detect yellow traps from a distance. The use of traps that are green outside would more accurately reflect the local abundance of hoverflies, as the insect would be likely to see the yellow stimulus only when above or close to the trap. Also, the addition of rose water significantly increased the number of M. fasciatum caught. From a suite of flowering plants chosen for their ability in other studies to increase hoverfly visit frequencies, laboratory experiments were conducted in France to determine the plant’s effectiveness at enhancing Episyrphus balteatus (De Geer) ‘fitness’, and to evaluate whether adult feeding on flowers was related to performance. Phacelia (Phacelia tanacetifolia Bentham cv. Balo), followed by buckwheat (Fagopyrum esculentum Moench cv. Katowase) and coriander (Coriandrum sativum L.) gave the optimal reproductive potential of female E. balteatus. There was no correlation between pollen and nectar consumption, and there was no discernible positive correlation between the quantity of pollen ingested and the resulting female performance. Phacelia and buckwheat were then studied as resource subsidies in the field in New Zealand. The effect of incorporating phacelia or buckwheat in the margins of 5 m x 5 m broccoli plots was tested for hoverfly activity and floral ‘preferences’. Hoverflies which had fed on phacelia and buckwheat pollen were found up to 17.5 m from the floral strips and females of M. fasciatum and M. novaezelandiae consumed more phacelia pollen than that of buckwheat in the field. These results support the choice of phacelia as an ideal floral resource subsidy in crops for enhanced biological control by these New Zealand species. The need for studying hoverfly movement in a large-scale field experiment was apparent from the field studies, so the next experiment was carried out in a field 450 × 270 m and flies were marked via their ingestion of the pollen of phacelia. The focus was on the proportion of flies having consumed the pollen. Although large quantities of pollen were found in some hoverfly guts, most did not contain phacelia pollen and very few were captured at 50 m from phacelia, compared with numbers at the border of the floral strip. A possible explanation was that hoverflies feed on a large variety of pollen species, reducing the relative attraction of phacelia flowers. Another possibility was that hoverflies dispersed from the phacelia away from the crop. Also, pollen digestion rates are likely to be a factor. Finally, a series of experiments was conducted in the field and laboratory to study hoverfly efficacy through oviposition and larval behaviour. In field experiments, female M. fasciatum and M. novaezelandiae laid more eggs where buckwheat patches were larger; however higher oviposition rates did not lead to improved aphid population suppression. In greenhouse experiments, larvae of E. balteatus could initiate a decline in aphid numbers at the predator: prey ratio 1: 8.3, however this control did not persist. Experiments in the laboratory showed that hoverfly larvae became more active and left the system while aphid numbers declined or numbers of larvae increased. This behaviour was caused by two factors: hunger and avoidance of conspecific larvae. Further experiments showed that the avoidance of conspecifics was caused by mutual interference rather than cannibalism. The results of this work highlight the importance of hoverfly dispersal ability. Given the observations of foraging behaviour of females and mutual interference observed between larvae, and the lack of success in CBC by hoverflies in experiments at the crop scale, it is essential to assess the impact of insect predators and parasitoids at a landscape scale.

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23

Dalebout, Merel Louise. "Species identity, genetic diversity, and molecular systematic relationships among the Ziphiidae (beaked whales)." Thesis, University of Auckland, 2002. http://wwwlib.umi.com/dissertations/fullcit/3083930.

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Beaked whales (family Ziphiidae) are one of the least known of all mammalian groups. The majority of species have been described from only a handful of specimens. Found in deep ocean waters, these species are widespread and often sexually dimorphic. Little is known of intra-specific variation in morphology, and many species are very similar in external appearance. A reference database of mitochondrial DNA sequences was compiled for all 20 recognised ziphiid species to aid in species identification. All reference sequences were derived from validated specimens, which were often represented only by bone or teeth. DNA was obtained from this ‘historic’ material using ‘ancient’ DNA methods. For three species, holotypes were sampled. Phylogenetic analyses using this database led to the discovery of a new, previously unrecognised species of beaked whale (Mesoplodon perrini), new specimens of Longman's beaked whale (Indopacetus pacificus), a species known previously from only two partial skulls and the synonymy of a third (M. traversii = M. bahamondi). Phylogenetic reconstructions based on sequence data from three mitochondrial and two nuclear loci (total, 2815 bp) using neighbour joining, parsimony, and maximum likelihood methods, resolved many of the sister-species relationships in this group. Inferred relationships among Mesoplodon beaked whales indicated that cranial and tooth morphology may be far more variable between closely related species than previously assumed. No support was found for a linear-progression of tooth form as suggested by Moore (1968) in his phenetic evaluation of relationships among the Ziphiidae. The geographic distribution of Mesoplodon species with similar or divergent tooth morphology is likely due to a combination of sexual selection and selection for species recognition. Both hypotheses predict similar patterns, such as dissimilar tooth morphology among species with sympatric or parapatric distributions. However, only sexual selection appears to offer an explanation for why there are so many Mesoplodon beaked whales. Investigation of mtDNA diversity among a number of beaked whale species indicated that nucleotide diversity was generally lower in this group than in other wide-ranging oceanic cetaceans. The cause of this low diversity was not clear but may be indicative of overall low abundance. Particularly low levels of diversity were found in Baird's beaked whale Berardius bairdii , Arnoux's beaked whale B. arnuxii and the northern bottlenose whale Hyperoodon ampullatus. Strong geographic structure in haplotype frequencies was observed among a worldwide sample of Cuvier's beaked whales Ziphius cavirostris.
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Simeonidis, Andrew. "Development of a mass rearing technique for the Tasmanian brown lacewing, Micromus tasmaniae Walker." Lincoln University, 1995. http://hdl.handle.net/10182/1302.

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Aphids are one of the most important insect pests of greenhouse crops yet to be controlled by biological means. Broad spectrum chemical control is becoming increasingly difficult to use in integrated pest management programmes, therefore, there is a need for a suitable biocontrol agent to be mass reared and released. The Tasmanian brown lacewing, Micromus tasmaniae Walker is an aphid predator that is found commonly throughout Australasia and has suitable characteristics that make it a candidate for mass rearing. A technique for rearing M. tasmaniae was developed. Eggs of M. tasmaniae were reared in batches of 50, 100 and 200 in 20 litre clear plastic containers. The oat aphid, Rhopalosiphum padi L. was fed to the larvae. The results revealed that the highest initial egg density (200 eggs per container) produced the cheapest adults at 22 cents per adult. However, mass rearing adults was considered not practical because of the high production cost, although, mass production of eggs is considered to be economically viable. The cost of producing one egg was 0.015 cents. M tasmaniae was maintained in mass culture for six generations. Simple experiments were carried out to monitor the quality of laboratory-reared insects. The 'wild' insect was used as a quality standard and comparisons with laboratory-reared insect populations were made. The fecundity, development rates and tolerance to pirimicarb, a carbamate insecticide, were determined. Fecundity was found to decline with successive generations in mass culture. The lacewing development experiment indicated that larval stages of each generation suffered the highest mortality rate and that between 35-45% of individuals emerged as adults. The tolerance of adults to pirimicarb did not alter over five generations. Recommendations for improving the mass rearing of M. tasmaniae are discussed.

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Murray, Tara J. "Effect of physiological and behavioural characteristics of parasitoids on host specificity testing outcomes and the biological control of Paropsis charybdis." Lincoln University, 2010. http://hdl.handle.net/10182/1558.

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An established host-parasitoid-hyperparasitoid system was used to investigate how the physiological and behavioural characteristics of parasitoids influence the outcomes of laboratory-based host specificity tests. The characteristics of the two pteromalid egg parasitoids, Enoggera nassaui (Girault) and Neopolycystus insectifurax Girault, were assessed and interpreted in regard to the particular host specificity testing methods used and the control of the eucalypt defoliating beetle Paropsis charybdis Stål (Chrysomelidae) in New Zealand. The physiology of N. insectifurax was examined to determine how to increase production of female parasitoids that were physiologically capable and motivated to parasitise P. charybdis eggs in laboratory trials. Neopolycystus insectifurax were found to be more synovigenic than E. nassaui. Provisioning them with honey and host stimuli for three days, and allowing females to parasitise hosts in isolation (i.e. in the absence of competition) was an effective means of achieving these goals. No-choice tests were conducted in Petri dish arenas with the four paropsine beetles established in New Zealand. All four were found to be within the physiological host ranges of E. nassaui and N. insectifurax, but their quality as hosts, as indicated by the percent parasitised and offspring sex ratios, varied. The results of paired choice tests between three of the four species agreed with those of no-choice tests in most instances. However, the host Trachymela catenata (Chapuis), which was parasitised at very low levels by E. nassaui in no-choice tests, was not accepted by that species in paired choice tests. A much stronger preference by N. insectifurax for P. charybdis over T. catenata was recorded in the paired choice test than expected considering the latter was parasitised at a high level in the no-choice test. The presence of the target host in paired choice tests reduced acceptance of lower ranked hosts. Both no-choice and choice tests failed to predict that eggs of the acacia feeding beetle Dicranosterna semipunctata (Chapuis) would not be within the ecological host range of E. nassaui and N. insectifurax. Behavioural observations were made of interspecific competition between E. nassaui and N. insectifurax for access to P. charybdis eggs. Two very different oviposition strategies were identified. Neopolycystus insectifurax were characterised by taking possession of, and aggressively guarding host eggs during and after oviposition. They also appeared to selectively oviposit into host eggs already parasitised by E. nassaui, but did not emerge from significantly more multi-parasitised hosts than E. nassaui. Enoggera nassaui did not engage in contests and fled when approached by N. insectifurax. Although often prohibited from ovipositing by N. insectifurax, E. nassaui were able to locate and begin ovipositing more quickly, and did not remain to guard eggs after oviposition. It is hypothesised that although N. insectifurax have a competitive advantage in a Petri dish arena, E. nassaui may be able to locate and parasitise more host eggs in the field in New Zealand, where competition for hosts in is relatively low. The biology of the newly established encyrtid Baeoanusia albifunicle Girault was assessed. It was confirmed to be a direct obligate hyperparasitoid able to exploit E. nassaui but not N. insectifurax. Field and database surveys found that all three parasitoids have become established in many climatically different parts of New Zealand. Physiological characteristics were identified that may allow B. albifunicle to reduced effective parasitism of P. charybdis by E. nassaui to below 10%. However, the fact that hyperparasitism still prevents P. charybdis larvae from emerging, and that B. albifunicle does not attack N. insectifurax, may preclude any significant impact on the biological control of P. charybdis. Overall, parasitoid ovigeny and behavioural interactions with other parasitoids were recognised as key characteristics having the potential to influence host acceptance in the laboratory and the successful biological control of P. charybdis in the field. It is recommended that such characteristics be considered in the design and implementation of host specificity tests and might best be assessed by conducting behavioural observations during parasitoid colony maintenance and the earliest stages of host specificity testing.

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Bowie, Mike H. "Evaluation of image analysis for studing mite behaviour." Lincoln University, 1996. http://hdl.handle.net/10182/1056.

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The aim of this study was to investigate the usefulness of image analysis for studying mite behaviour. Image analysis was used to convert video recordings of mites' locomotory behaviour into a series of x,y coordinates that, when joined, closely resemble the paths of mites. The coordinates were also used to calculate walking speed, direction of travel, turning frequency, turn bias and tortuosity. Two experimental arenas were developed and used to study the movement of three mite species: 1) a leaf disc arena for two-spotted spider mite, Tetranychus urticae Koch and European red mite, Panonychus ulmi (Koch); and 2), a cover-slip/tack-trap arena for Typhlodromus pyri Scheuten. Two-spotted spider mite exhibited a change in locomotory behaviour through a 48 minute period. Mites exhibited a significant decline in distance travelled, whereas the mean stationary time (per four minute interval) more than doubled, and the duration of stationary events increased steadily over the same period. A reduction in sampling frequency of mite coordinates from one per second to one every two seconds and every four seconds produced a 5% and 12% 'loss' in path length respectively. Sample period length was shown to greatly influence the results produced for some of the mean parameters calculated, however, a reduction in sample length from 3000 to 1500 coordinates was not considered to cause a major loss in information. The influence of the inherent mite movement could not be ignored and made it difficult to make decisions on the 'best' sample length to use. Some strong correlations were found between parameters used to analyse mite locomotory behaviour. In particular, arithmetic mean vector length, speed, total stationary time and total distance travelled were significantly correlated with each other. Mean angular deviation and weighted mean vector length, which both measure the degree of clustering around the mean heading angle, were strongly negatively correlated. Parameters which differentiated between 'straight' and 'tortuous' mite movement were found to be mean meander, absolute mean turn and fractal dimensions. Mean meander was thought to be the most 'powerful', while coefficient of a straight line, a commonly used parameter for measuring tortuosity, did not significantly differentiate between the two different behaviours. Frequency distributions of turns and standard deviations of the three mite species were very similar. All three species had a slight bias to turning right (clockwise) rather than to the left (counter-clockwise) and for each species certain angles occurred more often than would be expected in a 'perfect' normal distribution. A similar pattern also occurred with the frequency distribution of two-spotted spider mite heading angles, in that angles which were expected to occur more often, did not, and vice versa. The potential to use saturated salt solutions to control relative humidity on the arena was` demonstrated and indicated that relative humidity is likely to have an important influence on mite behaviour. Two-spotted spider mites appeared to move more quickly in an attempt to escape the unfavourable, extreme (10% and 95% R.H. at 25°C) moisture conditions. All three mite species displayed a characteristic edge-walking behaviour around the arenas. However, when 'edge' and 'non-edge' behaviours were compared, mean meander was the only parameter (of the parameters tested) which gave a significant difference. Behavioural responses of European red mite and T. pyri to sub-lethal (field rate) esfenvalerate were investigated and the results indicated that these mites did not seek the unsprayed halves of the arenas during the first 48 minutes. However, significant differences in most behavioural parameters to esfenvalerate residues were found with European red mite when whole arenas were compared. Image analysis is an extremely useful research tool for studying mite behaviour because of its ability to measure many parameters quickly. Careful choice of the environmental conditions, the sampling framework, and interpretation of data is essential for meaningful results.

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Travis, Georgia-Rose. "Boat preference and stress behaviour of Hector's dolphin in response to tour boat interactions." Diss., Lincoln University, 2008. http://hdl.handle.net/10182/303.

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Dolphins are increasingly coming into contact with humans, particularly where tourism is involved. It has been assumed that such contact causes chronic stress on dolphin populations. This study examined relatively naive populations of Hector's dolphins and their interaction with various watercrafts. Dolphins in New Zealand have been observed using theodolites and boat-based observations over the last two decades, particularly on the east side of the South Island at Akaroa, which is situated on the coast line of Banks Peninsula. This research was undertaken using shore-based theodolite tracking to observe boat activity around the coast of Lyttelton and Timaru and their associated Harbours. Observations were made mostly over two periods each of six months duration and included the months October through to March during the years 2000-2001 and 2001-2002. Observations made during a third period in 2005 were also incorporated for some of the analyses. Field investigations using a theodolite included more than 376 hours/site/season and recorded dolphin behaviour both with and without the presence of tour boats. Of primary interest were the tours, which ran regular trips to observe Cephalorhynchus hectori in their natural habitat. Hector's dolphins at both Lyttelton and Timaru were consistently observed with particular boat types and not with other types of water craft. Dolphins at Timaru exhibited a greater range of behaviours than those at Lyttelton. Stress-related behaviours such as an increase in swimming speed to open ocean and grouping behaviour were only observed in the presence of boats. Other potential stress behaviours, such as head slaps and repeated tail slaps, were only performed in the absence of boats. Observations implied that some generic dolphin behaviours, which often indicate stressed individuals may not apply to Hector's dolphins, and therefore question the assumption that all dolphin species behave in similar ways. We suggest that low-level tourist boat activity is not placing undue stress on the population. In addition to theodolite observations, tour boat based observations of Hector's dolphin were undertaken and behaviour at each site recorded for a focal animal. Tour boat-based observations concentrated on determining any preference to bow, stern, portside and starboard sides of the vessel. Dolphins consistently showed a preference in direction of approach and departure from tour vessels with a strong tendancy to the bow of the boat, and least with the stern. These results were similar irrespective of site or vessel. Behaviour data were also collected from tour boat vessels over 48 trips/season/site and the data divided into transitional behaviour groups, which included stress behaviours, association / interaction behaviour and neutral behaviour. Behavioural count and time data were collected to reflect the number of times and duration of behaviour occurrence, particularly in relation to transitional behaviours. Determining the presence of stress in Hector's dolphins varied between the data sets and indicated that time is a necessary factor when attempting to determine whether an individual or a general population is genuinely stressed. Quadrant preference and swimming direction in relation to the Black Cat were observed over six years, and both count and time data were collected with regard to behaviour. The results were consistent with preference in quadrant being expressed towards the bow of the boat and least with the stern. The count data suggested no significant impact on Hector's dolphin behaviour in the presence of the Black Cat over time, where time data indicated there was a transition over the years from neutral behaviour in the second year of tour boat activity, to positive behaviour in the third year of boat-activity and finally avoidance behaviour in the seventh year of tour boat activity at Lyttelton Harbour in response to the presence of the Black Cat.

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Peacock, Lora. "Eco-climatic assessment of the potential establishment of exotic insects in New Zealand." Lincoln University, 2005. http://hdl.handle.net/10182/1530.

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To refine our knowledge and to adequately test hypotheses concerning theoretical and applied aspects of invasion biology, successful and unsuccessful invaders should be compared. This study investigated insect establishment patterns by comparing the climatic preferences and biological attributes of two groups of polyphagous insect species that are constantly intercepted at New Zealand's border. One group of species is established in New Zealand (n = 15), the other group comprised species that are not established (n = 21). In the present study the two groups were considered to represent successful and unsuccessful invaders. To provide background for interpretation of results of the comparative analysis, global areas that are climatically analogous to sites in New Zealand were identified by an eco-climatic assessment model, CLIMEX, to determine possible sources of insect pest invasion. It was found that south east Australia is one of the regions that are climatically very similar to New Zealand. Furthermore, New Zealand shares 90% of its insect pest species with that region. South east Australia has close trade and tourism links with New Zealand and because of its proximity a new incursion in that analogous climate should alert biosecurity authorities in New Zealand. Other regions in western Europe and the east coast of the United States are also climatically similar and share a high proportion of pest species with New Zealand. Principal component analysis was used to investigate patterns in insect global distributions of the two groups of species in relation to climate. Climate variables were reduced to temperature and moisture based principal components defining four climate regions, that were identified in the present study as, warm/dry, warm/wet, cool/dry and cool/moist. Most of the insect species established in New Zealand had a wide distribution in all four climate regions defined by the principal components and their global distributions overlapped into the cool/moist, temperate climate where all the New Zealand sites belong. The insect species that have not established in New Zealand had narrow distributions within the warm/wet, tropical climates. Discriminant analysis was then used to identify which climate variables best discriminate between species presence/absence at a site in relation to climate. The discriminant analysis classified the presence and absence of most insect species significantly better than chance. Late spring and early summer temperatures correctly classified a high proportion of sites where many insect species were present. Soil moisture and winter rainfall were less effective discriminating the presence of the insect species studied here. Biological attributes were compared between the two groups of species. It was found that the species established in New Zealand had a significantly wider host plant range than species that have not established. The lower developmental threshold temperature was on average, 4°C lower for established species compared with non-established species. These data suggest that species that establish well in New Zealand have a wide host range and can tolerate lower temperatures compared with those that have not established. No firm conclusions could be drawn about the importance of propagule pressure, body size, fecundity or phylogeny for successful establishment because data availability constrained sample sizes and the data were highly variable. The predictive capacity of a new tool that has potential for eco-climatic assessment, the artificial neural network (ANN), was compared with other well used models. Using climate variables as predictors, artificial neural network predictions were compared with binary logistic regression and CLIMEX. Using bootstrapping, artificial neural networks predicted insect presence and absence significantly better than the binary logistic regression model. When model prediction success was assessed by the kappa statistic there were also significant differences in prediction performance between the two groups of study insects. For established species, the models were able to provide predictions that were in moderate agreement with the observed data. For non-established species, model predictions were on average only slightly better than chance. The predictions of CLIMEX and artificial neural networks when given novel data, were difficult to compare because both models have different theoretical bases and different climate databases. However, it is clear that both models have potential to give insights into invasive species distributions. Finally the results of the studies in this thesis were drawn together to provide a framework for a prototype pest risk assessment decision support system. Future research is needed to refine the analyses and models that are the components of this system.

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Warman, Guy Robert. "An integrated approach to the analysis of the circadian clock of the blow fly Lucilia cuprina." 1999. http://hdl.handle.net/2292/518.

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The Australian sheep blow fly Lucilia cuprina is an economically important dipteran pest whose circadian behavioural rhythms have been the subject of considerable scrutiny. The underlying biochemical nature of these rhythms however, has remained a mystery. The primary objective of this thesis was therefore to investigate the molecular control of circadian rhythms in L. cuprina using an integrative approach. To these ends, a dynamic molecular simulation model for L. cuprina was formulated using existing biochemical data on insect circadian clocks. The validity of this simulation model was subsequently tested at both molecular and behavioural levels. The basic molecular assumptions of the simulation model were tested by cloning a full length L. cuprina per cDNA and analysing its mRNA and protein expression levels. Isolation of the 4 Kb L. cuprina per cDNA revealed the conservation of three functional domains known to be important for circadian clock function; namely the PAS dimerisation motif (with 92% identity to D. melanogaster at the amino acid level), and the cytoplasmic and nuclear localisation domains (with 85% and 80% identity respectively). A fourth domain, the threonine-glycine (TG) repeat region, was also found to be conserved, but severely truncated in L. cuprina. No length variation was found in the TG repeat of flies collected from several different latitudinal zones, and no correlation was detected between sequences flanking the repeat and latitude of collection of flies. Thus, the contention that the TG repeat region plays a role in temperature compensation of the circadian clock is cast in doubt. Expression analyses (using quantitative RT-PCR) showed per mRNA levels to undergo diel oscillations with a period (24 h) and peak phase (Zt 12) consistent with the Drosophila data. PER-immunoreactive protein oscillations were also demonstrated, with peak immunoreactivity lagging approximately 3 h behind peak mRNA levels. The behavioural predictions of the model were tested by recording adult locomotor activity under different light regimes. The simulation model successfully predicted free-run, entrainment, the effect of short light pulses, and the effects of constant lighting on behavioural rhythms. Disparities between the simulated and real phase response cnrves for L. cuprina are hypothesised to be indicative of an ealier nuclear entry time of the PER-TIM dimer in L. cuprina compared with D. melanogaster. The three different approaches of simulation modellingo molecular analysis and behavioural investigation are integrated in the discussion in order to help provide a comprehensive explanation of circadian function in L. cuprina. The benefits of an integrated approach to the analysis of circadian function are discussed, as is the relevance of the present findings to the development of a clock-based control strategy for this economically important pest species.

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Ward, Darren Francis. "The distribution and ecology of invasive ant species in the Pacific region." 2007. http://hdl.handle.net/2292/2495.

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Invasive ant species represent a major threat to biodiversity through their detrimental impacts on native ecosystems. An important step to managing invasive ant species is determining the factors responsible for their current and potential distribution. This thesis examines the spatial distribution of invasive ant species at a range of scales. The focus is on the Pacific region, specifically Fiji and New Zealand, which have a relatively high number of invasive ant species. Taxonomic checklists of the ant fauna of Fiji and New Zealand are presented. Climate variables were used to model the distribution of, and predict suitable areas for, particular invasive ant species. In general, models had high evaluation success, especially for models that were built and tested within a region. However, the utility of models was far less when transferred and tested in new regions. A better understanding of how climate variables directly and indirectly affect a species is needed to improve the utility of species distribution modeling. On a finer spatial scale, habitat partitioning was evident at Colo-i-Suva Park in Fiji, where distinct ant communities were sampled from litter and canopy habitats. Results suggested that body size, habitat and resource utilisation interact to create opportunities for invasion, and influence the susceptibility of different habitats. Habitat also shaped the assembly of ant communities and mediated inter-specific competition in the Yasawa Islands, Fiji. Similarly, habitat was important in partitioning ant communities in New Zealand; endemic ant species were in forest, and invasive species in scrub and urban habitats. However, there was no evidence that inter-specific competition influenced community composition or the distribution of invasive ant species at regional or local scales in New Zealand. The extent and diversity of exotic ant species arriving at the New Zealand border was also investigated. A high proportion (>64%) of intercepted ants originated from the Pacific. The effectiveness of detecting exotic ant species at the New Zealand border ranged from 48-78% for different pathways, indicating a number of species remain undetected. Future work on invasive ants should focus on species-specific tolerances, and how the physical environment and small scale abiotic conditions influence distribution.

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Kiely, Aidan. "Functional and structural analyses of an olfactory receptor from Drosophila melanogaster." 2008. http://hdl.handle.net/2292/3342.

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In insects, olfaction is mediated by a large family of integral membrane proteins, called olfactory receptors (ORs), that mediate the transduction of odorant binding into a neuronal signal. A functional assay for insect ORs was developed utilising calcium imaging in Sf9 cells. The Drosophila melanogaster OR, Or22a, was expressed using transient transfection, and its activity measured by monitoring increased intracellular calcium levels using a calcium–sensitive dye. The interaction of the odorants ethyl butyrate, pentyl acetate and ethyl acetate with Or22a were both dose–dependent and sensitive, with EC50 values of 1.53 x 10−11 M, 5.61 x 10−10 M and 3.72 x 10−9 M, respectively. Furthermore, Or22a expressed in Sf9 cells has a similar response profile to a range of odorants previously tested in vivo. This assay system will provide a useful tool for the investigation of insect olfactory receptor structure and function. A consensus of eleven transmembrane (TM) domain prediction algorithms suggested a model for Or22a that contains seven TM domains, reminiscent of GPCRs. To test this model empirically, the membrane topology of Or22a was determined using epitope–tagging of predicted loops followed by immunochemistry. These experiments revealed that Or22a has seven TM domains but that its orientation in the membrane is opposite to that of GPCRs, having a cytoplasmic N–terminus. This orientation was also observed for Epiphyas postvittana Or1, which suggests that this inverted topology may be common to all insect ORs. To test whether Or22a forms higher order structures, fluorescence resonance energy transfer (FRET) between cyan and yellow fluorescent proteins inserted into the intracellular loops of Or22a was employed. The third intracellular loop interacts strongly with itself in homo–multimers, with interactions between the first and first loops and first and third loops also observed. These experiments show that ligand binding ORs can form multimeric structures in heterologous cells. The co–transfection of Or83b into S2 cells had no impact on these interactions, however Or83b is likely expressed in this cell line. Finally, models of how a ligand binding OR interacts physically with the ion channel Or83b are presented, and approaches that could be used to distinguish between these models are discussed.

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32

Morris, Michael Charles. "Photoperiodic control of development in the New Zealand leafroller moth Planotortrix octo Dugdale (Lepidoptera, Tortricidae)." 1990. http://hdl.handle.net/2292/1825.

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The aim of this study is to test for photoperiodic control of larval and pupal development in the New Zealand moth Planotortrix octo Dugdale. The photoperiodic response curves for larval and pupal development and especially for instar number at 17°C and 21°C indicate that a photoperiodic mechanism is involved. Superimposed on this response is the suggestion that daylength affects development rate directly, with larvae and pupae developing faster under longer photophases. This effect is especially strong for pupal development (Chapter 3). The effects of thermophotoperiods (Chapter 4), night interruption and resonance experiments (Chapter 6) provide further evidence for photoperiodic involvement. The response to resonance experiments suggests the involvement of an hourglass rather than a circadian mechanism. Larvae reared under short days accumulate significantly more lipids in the 5th and 6th instars than larvae reared under long days (Chapter 4). This finding, combined with the suppressed development rate and higher instar number under short days, suggests that a weak form of diapause may be present in this insect. This is significant in being the first recorded incidence of a photoperiodically induced diapause in a phyllophagous New Zealand insect for which a year round food supply is available (Chapter 1). By transferring insects from long to short days I found that long days have more influence than short days on larval development (Chapter 7). An attempt was made to measure juvenile hormone titres under long and short days using a Galleria bioassay. The test used was not sensitive enough however to measure any significant amounts of juvenile hormone (Chapter 8). Simulations of the experimental results were performed using a damped circadian oscillator model (Chapter 9). This model was considered the most appropriate to use, based on the experimental results and on a review of the literature (Chapter 2). Simulations showed good similarities with experimental results in most cases, but could not account for resonance responses.

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33

Kingsford, Michael John 1955. "Distribution patterns of fish during the planktonic period of their life history." 1986. http://hdl.handle.net/2292/1752.

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The static and dynamic distribution patterns of ichthyoplankton were investigated over a 4 year period (1981 - 1985) off the coast of Leigh, on the northeastern coast of New Zealand. Emphasis was given to horizontal and vertical distributions, and these were described on scales encompassing broad areas of the outer Hauraki Gulf and smaller areas of 1 - 100m. The ages of these small fish were also investigated by examining daily increments in the otoliths, and this allowed a more complete interpretation of distribution patterns. Sampling that was carried out at different distances from the mainland identified major differences in the distribution patterns of individual species. For example, pilchards were caught in high densities right across the continental shelf, whereas morid cod were restricted to the outer edge of the shelf. The most intensive investigations were carried out over the Summer months and these revealed large differences in the abundances of species. For instance, few bothids and triglids were captured in December, while large numbers were caught in January. The spawning activity of adults and broad scale differences between water masses were probably responsible for these distance and time related patterns. Large differences in the densities of ichthyoplankton were found at different localities within each area of the continental shelf (e.g. close to the mainland). Furthermore, detailed investigations of abundances at a single locality over a three day period showed large changes. These changing distribution patterns were related to the dynamics of localized hydrological features (e.g. tidally induced gyres). The presence of islands over the continental shelf also influenced the distribution of small fish. Some species were only found near land, regardless of the distance from the mainland. From ichthyoplankton hauls and direct observations made using SCUBA, it is argued that the behaviour of ichthyoplankton may have a strong influence on their distribution patterns. For example, tripterygiids and gobiesocids of a variety of ontogenetic forms were observed to aggregate and maintain their position in the shallow areas of rocky reefs. Large differences were found in the vertical distributions of fish and this was true in water columns from 1 - 40m in depth. Ichthyoplankters of a number of species had different depth distributions. Some species were consistently found near the surface (e.g. hemiramphids & mugilids) or near the bottom (e.g. eleotrids). For species found throughout the water column during the day, it was suggested that biological and physical stratification (e.g. thermoclines) strongly influenced relative densities at each depth stratum. Some species (especially engraulids & scombrids) migrated toward the surface at night. Migration patterns varied for each species and among times. The latter patterns were related to ambient light levels which changed with the phase of the moon. Small scale structure in the pelagic environment influenced the distribution of fish. Large numbers of fish were found around drift algae and when experimental algae were left to drift, small fish of several species (e.g. Monacanthids) were quickly attracted to it. A number of species were abundant in surface waters, but did not associate with drift algae (e.g. engraulids). For fish that were found around drift algae, the association may be important as a source of shelter and food. There was considerable seasonality in the occurrence of fish species around algae, and the abundance of total drift algae. Drift algae were most abundant over Spring and early Summer. The movements and accumulation of algae are discussed in relation to the potential influence it has on recruitment patterns of fish in nearshore environments. The distribution patterns of small fish were strongly influenced by the surface slicks of internal waves. Densities of small fish, drift algae, and zooplankton were higher in slicks than in rippled water adjacent to them. Slicks moved at 0.5 - 1.25 km per hour in the direction of shore. A consequence of aggregation in slicks, therefore, is that small fish may be transported onshore. It is suggested that the accumulation of zooplanktonic food in slicks may be important for the feeding of ichthyoplankters. Many of the fish found in surface waters, be it in open water or around drift algae, had adult fin-ray counts and were not considered to be larvae, according to current definitions. From information on the age and size of these fish it is suggested that the capacity of fish to settle at a variety of ages and sizes has probably been underestimated. Furthermore, the occurrence of physical processes such as slicks may influence the duration of the planktonic phase and subsequent settlement rates of fish into nearshore environments. The major findings were used to provide an overall picture of what happens during the planktonic phase of some species (Chrysophrys auratus, Parika scaber & tripterygiids), and these case histories are discussed in relation to current hypotheses concerning the ecology of ichthyoplankton.

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34

Kelly-Borges, Michelle. "The Order Hadromerida (Porifera: Demospongiae), taxonomy and relationships of the major families." 1991. http://hdl.handle.net/2292/1994.

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Despite advances of recent years no stable higher order classification of the Porifera has yet emerged. To address this problem, relationships at various taxonomic levels within the Order Hadromerida have been evaluated. Descriptions of new species of. Tethya, Aaptos and Polymastia from northern New Zealand are given in conjunction with a review and redefinition of specific diagnostic characters for these genera. A range of species, genera and families within the Hadromerida have been subjected to 18S rRNA sequencing. Using morphological and molecular sequence data together in phylogenetic analysis, the existing familial groups of the Hadromerida are confirmed and some rearrangement of genera is indicated following sequence alignment and comparison. These data serve as a baseline for molecular approaches to resolving relationships between other sponge groups.
Thesis now published as papers. Whole document restricted at the request of the author, but available by individual request, use the feedback form to request access.

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35

Robinet, Olivier Louis. "Ecology and Conservation of The Ouvea Parakeet, Eunymphicus cornutus uvaeensis (Loyalty Islands, New Caledonia)." 1997. http://hdl.handle.net/2292/2040.

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Whole Document restricted for copyright reasons.
The Ouvea Parakeet Eunymphicus cornutus uvaeensis, is an endangered bird endemic to Ouvea, Loyalty Islands, in the New Caledonian archipelago. Its population is estimated to be 300-600 birds, mainly in patches of forest in the north, with few parakeets in the centre and the south of the island. Its main habitat is high forest mixed with Melanesian fields. Within habitat distribution is very patchy, with an apparent site attachment during the breeding season. Radio tracking revealed that the home range of juveniles was small, and no dispersal was observed. The diet of the parakeets comprises the seeds and fruits of more than 23 plant species, including Ficus spp., Carica papaya and Rhamnella vitiensis. These plants have a long and asynchronous fruiting season, leading to an apparent abundance of food during the year. The number of breeding pairs was correlated with the density of potential nest sites in the three study areas, suggesting a nest site limitation. The length of the breeding season (August until January) allows the occurrence of double clutches. The parakeets nest in secondary cavities of only five species of trees (90% n Syzygium pseudopinnatum and Mimusops elengii). The clutch size is 2.9 eggs (range 2-4), of which on average 2.6 chicks hatch, 1.65 fledge, but only 0.75 per breeding pair is still alive 30 days after fledging. The main causes of loss are starvation of the third sibling due to hatching asynchrony, human harvest, and raptor predation after fledging. Ouvea is free of Ship Rat Rattus rattus and Norway Rat R. norvegicus. Kiore R. exulans, the rat present, is responsible for only a few predations at nests. The main predators are the Brown Goshawk Accipiter fasciatus, and humans that capture chicks to sell them as pets. 15-30 chicks are still captured every year and sold outside Ouvea. A population viability analysis of the Ouvea Parakeet shows that, with the current carrying capacity, this harvest is not sustainable and would eventually lead to extinction. Long-term survival would be best secured by establishing another population of 4-500 birds in the south of Ouvea, by increasing carrying capacity through habitat protection, nest site provision and restoration, decreasing the harvest and preventing the introduction of Ship Rat in Ouvea.

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36

Bergquist, Carol A. L. (Carol Anne Lillias). "Tui sociodynamics: foraging behaviour, social organisation, and use of song by tui in an urban area." 1989. http://hdl.handle.net/2292/2576.

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This thesis describes the behavioural ecology of the tui, Prosthemadera novaeseelandiae, a member of the Meliphagidae (honeyeaters), in the suburban Auckland region of the mainland of New Zealand. Tui are highly nectarivorous but observations show differences in degree of importance between the three food categories; nectar, fruit and insects according to season. when foraging for nectar tui are not responsive to flower colour but use all flowers with nectar concentrations greater than 7% (wt. per wt.) and use fruit when nectar availability falls. Foraging observations are significantly different for male and female tui with males taking more nectar and females taking more insects, in response to greater protein requirement as well as a result of status affecting foraging. There is also a seasonal difference in method of prey capture with the more energetically expensive hawking occurring in times of greater nectar availability or when very few insects in relation to nectar are taken. Colour-banded tui are shown to move in family groups over distances ranging from 5 to 35km in search of nectar for much of the year, but are localised into small foraging areas during breeding when nectar is abundant. Group members remain together and nest near each other, female offspring nesting closer to parents than male offspring. There is differential access to both natural and artificial food resources and the various asymmetries of sex, age and residency determine relative status at food sources but are not absolute. Loud song is the most conspicuous behaviour and is used to mediate avoidance between individuals and between groups. An artificial food source is partitioned temporally and spatially during breeding with the local higher status birds that use the feeders having significantly greater breeding success. Unlike results published for most passerines, both sexes of tui sing throughout the year and songs in their repertoire show sexual, seasonal, behavioural and individual variation. Pairs duet and both sexes will match songs with mates and with neighbours; resulting in apparent dialect areas corresponding with group boundaries. Avian spirochaetosis is identified as one of the causes of death in a population with 13-30% annual loss. Losses are readily compensated for as the nesting cycle is short and the breeding season is long. This, together with an opportunistic foraging strategy, great mobility and prolonged association in family groups explains the continued presence of tui in suburban areas.

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37

Goodwin, Elizabeth Elsa. "Rhythms, feeding and respiration of the oyster Crassostrea gigas." 1989. http://hdl.handle.net/2292/3338.

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Endogeneity of valve movement rhythms was demonstrated for the Pacific oyster Crassostrea gigas under constant conditions of temperature, light, salinity, water level and food availability. Rhythms continued for up to 6 weeks until the experiments were terminated. The rhythms showed a high degree of temperature compensation between 13 - 24˚C, but at 4˚C the free-running period was abnormally long. The length of the “open", or active phase decreased with temperature. Oysters collected from subtidal sites, as opposed to intertidal sites, also exhibited endogenous rhythms when held under constant condition. Oysters that received no food during a starvation trial were also rhythmic. Oysters subjected to artificial tidal cycles (HL 6:6h), show very precise synchronization of valve opening and closing to the cycles. Oysters were also be entrained to water disturbance cycles (6:6h) and light cycles (LD 12:12h), but the synchronization was not as precise. Rhythms were characterized by (1) split rhythms (2) spontaneous changes in the free-running period (3) spontaneous changes in rhythm clarity (4) spontaneous phase changes (5) and a Lot of "noise". These characteristics suggest that the underlying pacemaker controlling the rhythm may consist of more than one oscillator or more than one group of oscillators. No conclusive evidence could be found for semilunar or lunar rhythmicity. Cycles in the rate of algal cell clearance over a 24h period were shown by individual oysters. As a consequence of the variability between individuals combining the data tended to hide the existence of the rhythms. No evidence for rhythms in assimilation efficiency was found. Cell clearance rates were also affected by rising temperature over the range 4 - 25˚C, reaching a peak value at 17˚C. The rate of cell clearance fell sharply after 60 - 90min of feeding in a closed system, indicating that the rate was significantly affected by the decline in food availability. The time taken to open the valves and to start faeces production fell with increasing temperature. The amount of faeces production followed a similar trend. Assimilation efficiency fell with increasing temperature and many negative values were evident, suggesting contamination. However the total weight of faeces produced was less than that of food available implying that the oysters were assimilating inorganic material. The time taken to open the valves and the % oysters that opened their valves was adversely affected by declining salinity over the range 8.5 - 34‰. The time taken to start faeces production and. the % of oysters that produced faeces followed a similar trend. Assimilation efficiency was not significantly different at 25.5 and 34‰. AE% could not be measured at 8.5 and 17‰ due to a lack of normal faeces. Individual oysters showed cycles in the rate of oxygen uptake, but these were not synchronized to the tides or to each other. Pooling the data to calculate means cancelled out the individual rhythmicities. The presence or absence of food did not affect the expression of the cycle. The rate of oxygen uptake was positively correlated to oyster dry weight, temperature and salinity. Though for salinity the rate of oxygen uptake fell sharply below a critical salinity occurring between 10 - 13‰. Oysters held in sealed respirometers maintained a constant rate of oxygen uptake until a critical level of oxygen availability was reached, the rate of oxygen uptake dropped .significantly below this level. The slope of the regression lines (˚b˚), prior to reaching the critical oxygen level, increased with temperature, salinity and food concentration. But the time taken to reach the critical oxygen level, and the level of oxygen availability at which this occurred, was not significantly correlated with temperature, salinity or food concentration. The pattern of valve movement corresponded to the level of oxygen available. Valve movements became very frequent as the critical oxygen level was approached. Activity was reduced to occasional periods of valve movement after it was reached. The level of activity was adversely affected by declining salinity, but was not affected by the level of food availability.

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38

He, Xiong Zhao. "Reproductive behaviour of Aphidius ervi Haliday (Hymenoptera: Aphidiidae : a thesis presented in partial fulfi[l]ment of the requirements for the degree of Doctor of Philosophy in Plant Science (Entomology) at Massey University, Palmerston North, New Zealand." 2008. http://hdl.handle.net/10179/749.

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Aphidius ervi Haliday is a cosmopolitan parasitoid species of several major aphid pests on economically important crops. Prior to this research, little information was available on its reproductive behaviour. Emergence of A. ervi peaks during the first few hours of the photophase with males being protandrous. Females become sexually mature earlier than males and oviposit primarily in the photophase. Aphids parasitised in their early instars die before reproduction but those parasitised in later instars produce a limited number of progeny. Females prefer aphids of 3- to 5-d-old over the younger and older aphids for oviposition. Females ovipositing in 4- to 7-d-old aphids have more fitness gains in terms of progeny body size and egg load at emergence. Fertilised eggs are more likely deposited in large hosts and unfertilised eggs in small ones. Large individuals have greater longevity, large males father more progeny, and large females have higher fecundity, parasitism and greater ability in host searching. However, with increasing body size females gain more than males in longevity and fecundity but males gain more than females in the number of female progeny. Males can inseminate up to nine females and they carry about 82% effective sperm at emergence and replenish about 18% sperm during their adult life. Females adjust the oviposition and sex allocation strategies in response to increasing host density with higher number of aphids parasitised at higher host densities and lower proportion of female progeny produced at lower host densities. Males play an active role in mating behaviour. Males having mating experience, and being large or younger, respond to females more quickly and perform better courtships resulting in higher mating success. Males prefer larger and younger females for mating probably because the latter have greater reproductive potential. Males optimize the use of their sperm based on the availability of their sperm and the reproductive status (age) of females. The switchingoff of female receptivity of male mating attempt after the mating is a gradual process. Some females accept the second males within 1 minute since the termination of the first mating. The shorter mating period in the second mating suggests that females remate probably due to the gradual process of switching-off of female receptivity rather than the insufficient sperm transformation during the first mating. Males prolong their mating duration in male-biased operational sex ratio to reduce the probability of female remating.

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39

Hemmings, Alan Dudley. "Cooperative breeding in the skuas of the Chatham Islands." 1995. http://hdl.handle.net/2292/974.

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Cooperative breeding, widely reported in birds, is found in <1–5% of territories in some populations of the Brown skua, Catharacta lonnbergi. In the New Zealand region, up to 30-50% of skua territories may be occupied by trios or larger groups. This study examines its occurrence at the Chatham Islands, east of New Zealand. Here 16% of territories are occupied by trios and 2% by groups. All members of skua trios and groups participate in sexual and other breeding activity, and the associations arc thus communal. Sexual discrimination of breeding birds by morphometric measurements shows that all communal groups known since 1978-79 have been polyandrous. These groups are long-lived associations, some of which are known to have persisted for at least 14 years. Trios are as long-lived and stable as pairs, and birds on communal territories do not move from them even when an appropriate-sex space becomes available on an adjacent pair territory. The members of trios are not close kin. All members of communal associations participate in territorial defence and chick rearing. In trios, the males appear to be equals, although in any one year the actual paternity of offspring may reside with only one of them. Overall reproductive success for Chatham Island skuas is high, for both pairs and communal groups, compared with other populations. However, communal trios and groups have lower reproductive success than pairs even over a l0 year period, particularly when considered on a per adult basis. Furthermore, no improvement in chick ‘quality’ is discernible. Unusually for skuas, the breeding population at the Chatham Islands is non-migratory. Skuas are present on their breeding territories during the winter, and exhibit characteristic territorial and agonistic behaviours, albeit at lower intensity than during the breeding season. It is suggested that communal breeding in this skua population is not adaptive per se, but a secondary consequence of year-round residence. This is a departure from the conventional resolution of communal breeding. Residence is facilitated by benign climatic conditions and year-round prey availability. When territory space becomes available outside the breeding season, in a small number of cases more than a pair of skuas are able to establish themselves. Thereafter, trios and larger groups persist and behave in the same manner as pairs. The flux between trios and pairs when birds are lost is determined, in part, by the sex of that bird. Thus a trio which loses its one female will ‘acquire’ a replacement female and persist as a trio, whereas a trio which loses one of its two males will thereafter continue as a pair. Keywords: Cooperative breeding, communal breeding, polyandry, Stercorariidae, skuas, skua trios, skua behaviour, skua breeding, Chatham Islands
Chapter 1 previously published as: Cooperative breeding in the Skuas (Stercorariidae): History, distribution and incidence. Journal of the Royal Society of New Zealand 24: 245-260 (1994). Publisher version available at http://www.royalsociety.org.nz/Site/publish/Journals/jrsnz/1994/default.aspx
Chapter 2 previously published as: Winter territory occupation and behaviour of Skuas at the Chatham Islands, New Zealand. Emu 90: 108-113 (1990). Publisher version available at http://www.publish.csiro.au/nid/96.htm
Chapter 3 previously published as: Communually breeding Skuas: Breeding success of pairs, trios and groups of Catharacta lonnbergi on the Chatham Islands, New Zealand. Journal of Zoology, London 218: 393-405 (1989). The definitive version is available at www.blackwell-synergy.com

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40

Freeman, Debbie. "The ecology of spiny lobsters (Jasus edwardsii) on fished and unfished reefs." 2008. http://hdl.handle.net/2292/3363.

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Knowledge of the interactions among species and communities is vital for their management and protection. Increasingly, the role of marine protected areas in this regard is being recognised, primarily because of the potential for previously-harvested species to increase in density and biomass, and the linkages among species to be restored. Monitoring and research was conducted within and surrounding two marine reserves on the east coast of the North Island of New Zealand – Te Tapuwae o Rongokako, near Gisborne, and Te Angiangi, south of Napier. The aim was to describe the biological characteristics of spiny lobsters (Jasus edwardsii) in the absence of fishing, and to describe the effects of fishing and protection on lobster populations and the communities of which they are a component. Diver and pot surveys showed that lobsters were significantly more abundant within the reserves than in the surrounding fisheries and that the populations were comprised of a larger proportion of legal-sized individuals. Higher female fecundity within Te Tapuwae o Rongokako Marine Reserve compared with the surrounding fishery was proposed to be primarily a result of increased availability of large males within the reserve. The impact of the fishery on lobsters was also evidenced in the lower tail width to carapace length ratio of the fished population compared to the population within Te Tapuwae o Rongokako Marine Reserve, due to the minimum legal size for Jasus edwardsii in New Zealand being based on tail width. The largest tagging study ever to be conducted in a New Zealand marine reserve showed that sublegal male lobsters within Te Tapuwae o Rongokako Marine Reserve were growing on average faster than the same sized individuals outside the reserve, potentially as a result of the effects of handling and / or size-selective fishing. A decrease in growth rate over time was recorded in male lobsters within the reserve, which coincided with an increase in catch per unit effort and may indicate that density-dependent effects are operating. Distinct seasonal movements of tagged lobsters were recorded, with the vast majority of movements taking place within reefs. Where the boundaries of the reserve crossed reef habitat, significant movement of lobsters across the boundaries occurred. Lobsters within Te Tapuwae o Rongokako Marine Reserve not only exhibited cannibalistic behaviour but foraged during the day, including on intertidal reef platforms at high tide, potentially as a behavioural response to increased competition for food – behaviour not previously reported for this species. Outside the reserve, lobster bait apparently provided an alternative protein source but despite this supplementation of diet, these lobsters were in poorer nutritional condition, as evidenced by their lower body weights relative to carapace length and tail width for both sexes. Lobsters outside the reserve were also significantly more affected by a bacterial infection associated with handling, than lobsters within the reserve. These findings have significant implications for fisheries management and for the design and management of marine protected areas (MPAs). This study demonstrates that many of the biological parameters used in evaluating harvest strategies in the New Zealand lobster fishery may be biased unless collected from populations with a natural size structure, such as may occur within marine protected areas.

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41

Fitness, Josephine. "Wellington geckos meet Wairarapa geckos : hybridisation between two genetically and morphologically distinct populations of the New Zealand common gecko complex (Hoplodactylus maculatus) : a thesis presented in partial fulfilment of the requirements for the degree of Masters of Science in Zoology at Massey University, Palmerston North, New Zealand." 2010. http://hdl.handle.net/10179/1656.

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The purpose of this study was to use molecular techniques and morphological measurements to set out to find whether a hybrid zone exists between two coastal populations of the common gecko (Hoplodactylus maculatus), on the Wellington south coast. I collected geckos from five sites in a coastal transect from the population of small geckos to the large geckos. Using four genetic loci, one mitochondrial (16S) and three nuclear (Rag-1, Rag-2, C-mos), I was able to determine that the coastal populations do have geneflow, however each population maintains some unique alleles. Morphological evidence reveals a significant difference in gecko sizes from Turakirae Head and those caught at Ocean Beach, separated by just 15 km. Adult geckos at Turakirae Head are on average 10mm smaller (snout-to-vent) than adult geckos at Ocean Beach, representing almost a doubling in average weight. The centre of the steep frequency clines of four characters is coincident and the widths are concordant. The narrower morphological clines indicate stronger selection on the size of the gecko, than on genetic loci.

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42

Jones, Erica Anne. "Characterisation of limb development and locomotion in the brown kiwi (Apteryx mantelli) : a thesis presented in partial fulfillment of the requirements for the degree of Master of Science in Zoology at Massey University, Palmerston North, New Zealand." 2010. http://hdl.handle.net/10179/1641.

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This thesis covers broad topics concerning limb growth and development and their effects on locomotion in the brown kiwi (Apteryx mantelli). I begin by describing the morphological features of a collection of unknown-age wild kiwi embryos from early development to point of hatch. Using these features, I assign developmental stages to each embryo and compare the progress of development to the same-staged ostrich and chicken embryos. Measurements of the hindlimb, bill and crown-rump length are used to develop an aging scheme based on comparisons with the ostrich and the chicken. The ostrich model and chicken model create age predictions for the unknown aged kiwi embryos. One kiwi embryo was of known age and both models gave identical predictions for this marker embryo, but gave differing predictions for all other kiwi embryos. Using captive-reared kiwi chicks, I characterise hindlimb, bill and bodyweight growth from the time of hatch to 3 months of age. Growth patterns are very linear within this time period for all measurements but bodyweight. Female kiwi hatch with longer bills than males, but the growth of both sexes converges by the end of the 3-month period. Growth of bodyweight in the males slows earlier than in females. Bodyweight and bill length were then compared to a wild population of kiwi. Captive-reared chicks were found to hatch with shorter bills than the wild birds and to increase in bodyweight at a faster rate than wild birds. Rapid weight gain has been implicated in developmental limb deformities in other precocial and long-legged birds and has the potential to produce similar results in captive kiwi. I further studied the movement of the hindlimb during locomotion in two adults and one juvenile kiwi by filming them while they were walking on a treadmill. Kinematic parameters were measured from the video recordings and compared to overground parameters from another study. Similarity between the treadmill and overground locomotor parameters validates the use of a treadmill in studying kiwi locomotion. None of the birds achieved the theoretical transition from a walk to a run at a duty factor of 0.5. After normalising for size, the juvenile showed a longer stride length and lower stride frequency with increasing speed than the adults. Lateral head oscillations were observed during the stride cycle, which I propose having a sensory function as well as a biomechanical one.

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43

Thongphak, Duangrat. "Systematics of the Australian longicorn beetle genus Uracanthus Hope 1833 (Coleoptera: Cerambycidae: Cerambycinae: Uracanthini) : a thesis presented in partial fulfillment of the requirements for the degree of Doctor of Philosophy in Plant Science (Entomology) at Institute of Natural Resources, Massey University, Palmerston North, New Zealand." 2007. http://hdl.handle.net/10179/1397.

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Uracanthus is a large group of longicorn beetles in the Australian Region. The larvae of this genus are borers of at least 31 genera of trees and parasitic plants, including some economically important crops such as citrus, litchi, peach, plum, and apricot. Several species are important pests of orchards. Adults visit flowers of various tree species and are attracted to the light. In this thesis, I undertook a thorough taxonomic revision, analysed the phylogeny using morphological and molecular characters, and appraised biogeographic distribution of the genus. In the taxonomic revision, I redefine the scope of the genus, describe and illustrate new and previously known species, and provide a key to all species. The revised Australian Uracanthus includes 39 species, eight of which are established as new to science: U. pseudogigas sp. nov., U. maculatus sp. nov., U. griseus sp. nov., U. bicoloratus sp. nov., U. perthensis sp. nov., U. punctulatus sp. nov., U. quadristriolatus sp. nov., and U. bistriolatus sp. nov. Six new synonyms are proposed (senior synonyms last): U. multilineatus McKeown with U. ventralis Lea, U. dentiapicalis McKeown with U. parvus Lea, U. marginellus Hope and U. inermis Lea (not Aurivillius) with U. bivittatus Newman, U. fuscostriatus McKeown with U. lateroalbus Lea, and U. daviumbus Gressitt with U. longicornis Lea. Dorsal views of all species are presented as photographs, terminalia of both sexes illustrated, and distributions mapped. Brief comments are also given on the biology of this genus. In the full morphological phylogenetic analyses of all 39 species, I use 55 informative characters and cladistic method to test the monophylies of Uracanthus and its species groups. My results show that the monophylies of the genus and seven species groups are confirmed. However, several species groups still need additional steps to become monophyletic and are currently considered paraphyletic. In the molecular phylogenetic studies, due to the situations beyond my control (difficulties of extracting DNA from some old species and prohibitions of extracting DNA from type specimens), I analyse only 21 species. I extract and amplify the cytochrome oxidase I (COI) region of the mtDNA from 21 species and perform a phylogenetic analysis using molecular characters. To make the molecular phylogeny comparable to the morphological phylogeny, I also cladistically analyse the phylogeny of these 21 species using morphological and combined morphological-molecular characters. A comparison of trees obtained from morphological, mtDNA and combined data shows that the relationships of several closely related taxa remain constant, for example, the sister relationships of U. gigas + pseudogigas, U. insignis + punctulatus, and U. acutus + loranthi. However, the placement of U. insignis and U. punctulatus on the phylogenetic trees varies from the most basal in the full morphological analysis to the highly derived in the combined and molecular analyses. Considering the amount of available data is more limited in the molecular analysis than in the morphological analysis, the molecular phylogeny presented in this study should be interpreted with caution. The Uracanthus fauna can be divided into five subregions: the Kosciuskan, Western and Eyrean in southern and central Australia, and the Torresian and Timorian in northern Australia. The fauna are richest with highest endemism in the Kosciuskan and Western. The Kosciuskan and Western are similar in faunal composition and closely related; the Eyrean has probably acted as a faunal exchange transit area between the Kosciuskan and Western, and the two northern Australian subregions have no endemic species. When the areas of endemism of each species are attached to the phylogenetic tree generated from the full morphological analysis, a clear picture of the distribution patterns of species groups in relation to phylogeny is obtained. It is suggested that the speciation and species radiation of Uracanthus may have occurred first in the Kosciuskan, then in the Western, and finally in the Eyrean, Torresian, and Timorian.

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Stockin, Karen A. "The New Zealand common dolphin (Delphinus sp.) : identity, ecology and conservation : a thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Zoology, Massey University, Auckland, New Zealand." 2008. http://hdl.handle.net/10179/790.

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Common dolphins (genus Delphinus) are poorly understood within New Zealand waters. Prior to this study, most information relating to the taxonomy, population structure, diet and pollutant loads of this genus relied upon untested assumptions. Furthermore, factors affecting the occurrence, demographics and habitat use of common dolphins in the Hauraki Gulf remained unknown. This lack of empirical data has resulted in the inadequate recognition and management of New Zealand Delphinus. Inappropriately classified by the New Zealand Threat Classification System, the anthropogenic impacts that affect this genus have clearly been overlooked. The present study examines behaviour of common dolphins in the Hauraki Gulf and details analyses undertaken on tissue samples collected from around New Zealand. Results detailed here challenge many of the untested assumptions about this genus within New Zealand waters. The taxonomy of New Zealand common dolphins was assessed using 92 samples analysed for 577 base pairs (bps) of the mtDNA control region (D-loop). New Zealand samples were compared with 177 published sequences from eight other populations from around the world. New Zealand Delphinus exhibited a high genetic variability, sharing haplotypes with both short- (D. delphis) and long-beaked (D. capensis) populations. Indeed, the New Zealand population showed significant genetic differentiation when compared with most other populations world-wide. Furthermore, intrapopulation analyses revealed significant genetic differentiation between Hauraki Gulf individuals and other common dolphins sampled within New Zealand waters. Results suggest habitat choice and site fidelity may play a role in shaping the fragmented population structure of New Zealand Delphinus. Data relating to the occurrence and demographics of common dolphins in the Hauraki Gulf region were collected during boat-based surveys between February 2002 and January 2005. In total, 719 independent encounters, involving one to > 300 common dolphins were recorded. Dolphin presence was significantly affected by month, latitude and depth. Group size varied significantly by month, season, depth, sea surface temperature (SST) and latitude, and was highly skewed towards smaller groups comprising fewer than 50 animals. Calves were observed throughout the year but were most prevalent in the austral summer months of December and January. Group composition was significantly affected by month, season, depth and SST. The yearround occurrence and social organisation of Delphinus in Hauraki Gulf waters suggest this region is an important nursery and potential calving area. The effects of diel, season, depth, sea surface temperature, and group size and composition on dolphin behaviour were investigated using activity budgets. Foraging and social were the most and least frequently observed behaviours, respectively. A correlation between group size and behaviour was evident, although behaviour did not vary with the composition of dolphin groups. Resting, milling and socialising animals were more frequently observed in smaller groups. Foraging behaviour was prevalent in both small and large groups, suggesting foraging plasticity exists within this population. Behaviour differed between single- and multi-species groups, with foraging more frequent in mixed-species aggregations, indicating the primary mechanism for association is likely prey-related. Stomach contents analysed for forty-two stranded and eleven commercially by-caught individuals collected from around North Island, New Zealand between 1997 and 2006, revealed arrow squid (Nototodarus spp.), jack mackerel (Trachurus spp.) and anchovy (Engraulis australis) as the most prevalent prey. Stranded individuals and dolphins bycaught within neritic waters fed on both neritic and oceanic prey. Moreover, a mixed prey composition was evident in the diet of common dolphins by-caught in oceanic waters, suggesting inshore/offshore movements of New Zealand Delphinus on a diel basis. Additionally, prey differences were also evident in the stomach contents of common dolphins sampled from within the Hauraki Gulf. Trace elements, polychlorinated biphenyls (PCBs) and organochlorine (OC) pesticide levels were determined in five stranded and fourteen by-caught Delphinus sampled from around New Zealand between 1999 and 2005. Generally, levels of trace elements were low. However, concentrations of OC pesticides were similar in range to those previously reported for Hector’s (Cephalorhyncus hectori) and common bottlenose dolphins (Tursiops truncatus). Organochlorine pesticides dieldrin, hexachlorobenzene (HCB), o,p’-DDT and p,p’-DDE were present at the highest concentrations. Markov chain models were used to assess the impact of tourism activities on Delphinus within the Hauraki Gulf. Foraging and resting bouts were significantly disrupted by boat interactions. Both the duration of bouts and the time spent in these two behavioural states decreased during boat interactions. Additionally, foraging dolphins took significantly longer to return to their initial behavioural state in the presence of a tour boat. Impacts identified are similar to those previously reported for the common bottlenose dolphin, a coastal species typically considered to be more susceptible to cumulative anthropogenic impacts. Data presented here reveal the nature and apparent susceptibility of New Zealand common dolphins to human-induced impacts, namely fisheries by-catch, pollution and tourism. This in conjunction with taxonomic uncertainty, lack of abundance estimates and the year-round use of inshore waters for feeding, clearly warrants immediate attention from managers. Furthermore, the current threat classification of New Zealand Delphinus should be reconsidered in light of population uncertainties, and in view of the susceptibly to human-induced impacts revealed by the present study.

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Riet, Sapriza Federico Germán. "Milk composition of the New Zealand sea lion and factors that influence it : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Zoology at Massey University, Palmerston North, New Zealand." 2007. http://hdl.handle.net/10179/1440.

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The objectives of the present study were to: 1) describe the gross chemical milk composition of the New Zealand sea lion (NZSLs), Phocarctos hookeri, in early lactation; 2) validate an analytical method for sea lion milk composition; 3) investigate a series of temporal, individual and dietary factors that influence the milk composition of the NZSL and; 4) investigate the temporal and spatial differences in the fatty acids signatures of sea lion milk. A comprehensive literature review revealed that data on milk composition in otariid species is either missing or limited, that to be able to fully describe their milk composition extensive sampling was required and that the temporal, maternal and offspring factors that influence milk composition in pinnipeds are poorly understood. The review identified that considerable work has been conducted to infer diet via the application of fatty acids signature analysis of milk and blubber. There are many factors (i.e. metabolism, de novo synthesis and endogenous sources) that contribute to the differences in fatty acid composition between the diet and milk or blubber. Milk samples from NZSL were used to test whether a new method would give similar results as the standard methods of milk analysis. Agreement between analytical methods for milk components was assessed using different measures of statistical fitness and the results indicated that the new method was comparable to the standard methods and applicable to the milk of sea lions, pinnipeds and to ecological studies of lactation. Milk from NZSLs was collected over a period of seven years (1997, 1999 to 2003, and 2005) in early lactation to describe the composition of milk of NZSL and to test for differences between years. The results indicated that: i) the milk protein concentration was comparable to other species of pinnipeds; ii) the milk fat concentration and the milk energy content of NZSL is the lowest reported for otariids in early lactation; however iii) the milk fat concentration was significantly different between years. These results suggested that the milk composition of NZSLs was influenced by annual changes in the environment; however, there may be other unidentified factors. Month, maternal body condition, age, body weight and length, offspring sex and age, and attendance pattern were compared with milk components. The results identified that month, maternal body condition and age significantly affected milk fat concentration. These results and the fact that maternal body condition varied significantly between years and mothers nursing male pups had lower body condition and produced milk lower in energy content suggested that local food resources along with other unidentified factors have an effect on the reproductive success of NZSLs. To test whether the fatty acid signature analysis (FASA) of lipid rich tissues (milk, blubber and serum) of otariids could be used to infer diet a mixture of vegetable oil (with distinctive fatty acid signature) was fed to 24 lactating NZSL and tissue samples were collected at different time intervals. Significant increases in the concentration of specific fatty acids in serum and milk were observed with peaks within 12hrs and 24hrs respectively of ingestion. Concentrations in milk remained elevated for up to 72hrs and there were differential rates of incorporation into milk. These findings confirm the potential of FASA to infer the composition of the diet. The variation in milk fatty acid signatures from lactating NZSL from four years (1997, 2003, 2004 and 2005) of sampling were measured in order to test whether differences occurred between years. Fatty acids signatures from five potential prey species including the commercially important arrow squid were incorporated into the analysis to associate the changes in milk fatty acids with a shift in prey choice. The results indicated that milk fatty acid signatures were different in 1997 and 2003; however, it was not possible to relate these differences to the five prey species. The variability in the annual arrow squid catch data suggested that local food resources around the Auckland Islands may also be variable. In conclusion, the milk produced by the NZSL has the lowest concentration of fat and energy in early lactation reported for any otariid species. The main factors that contributed to changes in milk quality were stage of lactation, year and maternal body condition. The yearly variation in the quality of milk appears to be a result of their lactation strategy or to variable local food conditions that also affect maternal body condition. Therefore monitoring the annual milk quality may be a means to monitor the health of a pinniped population and potential management tool for pinniped species. This thesis has shown that annual changes in the diet of NZSL can be assessed with milk fatty acid signatures.

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Dissertations / Theses on the topic 'Fields of Research – 270000 Biological Sciences – 270500 Zoology'

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