Dissertations / Theses on the topic 'Alien insect'

Thesis (MSc)--Stellenbosch University, 2008.
ENGLISH ABSTRACT: Alien trees, Pinus spp. and Eucalyptus spp., affect ants negatively in the Cape Floristic Region (CFR), a global biodiversity hotspot in South Africa. They reduce ant abundance and species richness, thus also changing ant assemblage structure. This is alarming, because almost 1300 species of plant species in the CFR are dispersed by certain indigenous ants, and thus there is concern for an indirect effect on indigenous plant assemblages. One of the most impacting ant species on seed dispersal is the invasive Argentine ant (Linepithema humile (Mayr)), which discards seeds outside its nest, where they do not germinate. Ten sites, on Vergelegen Wine Estate, were selected to explore these effects of alien plants. These varied from invaded to non-invaded sites. Each site consisted of six sampling points, which in turn consisted of four pitfall traps left out for seven days, during December 2005, February 2006, May 2006 and September 2006. Forty species of ant were sampled, and various analyses used to illustrate the comparative effects of plant invasion. All analytical methods showed that invasive alien plants had a significant impact on the abundance and richness of the ant species assemblage, by creating a dense canopy cover that changed the abiotic environment of the epigaeic ants’ habitat. Furthermore, increased alien tree invasion correlated significantly with Argentine ant abundances. The Argentine ant displaced Pheidole capensis and Camponotus spp., while it decreased the abundances of commonly-occurring indigenous ants, such as Lepisiota capensis and Plagiolepis spp. Displacement by the Argentine ant may be a result of indirect competition for food resources. The effects of invasive aliens are synergistic in that there is a cascade effects from initial plant invasions to subsequent animal invasion.
AFRIKAANSE OPSOMMING: Indringer bome, Pinus en Eucalyptus, affekteer miere op negatiewe wyse in die Kaap Florsitiese Streek (KFR), ‘n area in Suid Afrika van belang t.o.v. globale biodiversiteit. Hierdie uitheemse indringer bome verminder hulle hoeveelheid en spesies rykheid. Die bogenoemde is kommerwekkend omdat meer as 1300 plant spesies in the KFR versprei word deur miere. Die verandering in hoeveelheid en versameling van inheemse miere kan dus ernstige implikasies hê op die saad verspreiding van inheemse plant spesies. Een van die mees verwoestende effekte op saad verspreiding is veroorsaak deur die indringer Argentynse mier (Linepithema humile (Mayr)), wat sade neer werp buite hulle neste, waar hulle nie suksesvol kan ontkiem nie. Tien monsterings-tereine was geselekteer om die bogenoemde effekte te ondersoek op Vergelegen Landgoed. Hierdie het afgewissel van indringer tot skoon tereine. Elke terrein is op ses versamelings-plekke gemonster, met vier pitvalle, wat oopgelê het vir sewe dae gedurende Desember 2005, Februarie 2006, Mei 2006 en September 2006. 40 spesies van miere was gemonster. Indringer plante het ‚n betekenisvolle impak gehad het op die hoeveelheid en rykheid van die mier gemeenskappe, deur die skepping van ‚n dig baldakyn wat die abiotiese omgewing van die miere se habitat verander het. Die vermeerdering van indringer plante veroorsaak die vermeerdering van Argentyne miere. Kanonieke Mede-Respons Analise illustreer dat die Argentynse mier Pheidole capensis en Camponotus spp. verplaas het, terwyl dit ander inheemse mier getalle verminder het, soos Lepisiota capensis en Plagiolepis spp. Die verplasing deur die Argentynse mier mag die resultaat wees van indirekte wedywering vir hulpbronne. Die effekte van indringer species is dus sinergisties deur dat ‚n kaskade effek ontstaan vanaf plant tot dier indringer spesies.

The present study aims to investigate the diversity and flight activity of Staphylinidae in a citrus orchard of the Catania Plain (Sicily) using different sampling methods (car-net, window traps and pit-fall traps). The study looks at the complex of flying rove beetles with the aim of defining preliminarily the faunistic and zoogeographical structure of this family in the study area. A second aim of the study is to investigate, using window-traps and pit-fall traps, the spatial distribution of flying staphylinids inside the orchard and in adjacent habitats. The use of window traps and car-net allowed to analyse the monthly and daily flight activity of staphylinids and to analyse the flight circadian rhythm and its seasonal variation. Monitoring of wind and temperature also allowed to evaluate the effects these environmental factors on the flight activity. 170 taxa (species, subspecies and 20 morphospecies) of Coleoptera Staphylinidae were collected. Most of the species are eurytopic species or related to substeppic or steppic environments, usually saprophyles with broad ecological valence. 5 species (Pella leonhardi, Pronomaea sicula, Quedius caelebs, Tasgius globulifer evitendus and Tasgius pedator siculus) are endemics to Sicily, 1 species (Oxypoda flavissima) is new for Italian fauna, 11 species (Acrotona muscorum, Amischa decipiens, Amischa forcipata, Atheta testaceipes, Carpelimus fuliginosus, Dacrila pruinosa, Lithocharis nigriceps, Micropeplus porcatus, Neobisnius lathrobioides, Outachyusa raptoria, Pycnota paradoxa e Trichiusa immigrata) are new for Sicilian fauna. The chorological spectrum is coherent with the environment where the research took place: a large orchard plain characterized by prolonged summer aridity. The results of the window trap sampling show significant differences in the abundance of the flying species between open areas inside the orchard characterized by herbaceous vegetation (Track) and the inside of the parcels of citrus grove (Citrus). On the other hand the Spearman rank correlation analysis demonstrates that the faunistic structures of this stations are similar. Comparison between sampling with pit-fall traps and with windows traps one shows that these two sampling methods basically differ by the taxa captures frequencies, in addition to the complete absence of Ocypus o. olens in the window traps. The occurrence of the maximum frequency of catches in the window traps in the spring (often in contrast with car-net data) suggests that in this period blooming and fruits marcescence processes are an attractive stimulus which causes an increase of flight activity. Hourly sampling with car-net highlighted, in the most abundant species, that flight has a circadian rhythm characterized by morning and afternoon peaks with a break or a decrease at midday. The beginning of flight activity coincides with dawn in summer period in Gabronthus maritimus and in Alaeocharinae and Oxytelinae (not examined at species level). Flight activity s end takes usually place at sunset or twilight. Flight activity after dusk up to an hour after sunset has been detected in the Paederinae Scopaeus debilis, Hypomedon debilicornis, Astenus b. bimaculatus and Astenus pallidulus. There are also seasonal variations of the distance of morning and afternoon peaks from dawn and sunset: in winter they are far away from dawn and from sunset, in spring the afternoon peak gets closer to sunset, in summer morning peak moves closer to dawn and the afternoon one overlaps sunset, in autumn this two peaks move away from dawn and from sunset again. From autumn to spring the beginning of flight activity is conditioned by temperature. High temperature seems to cause the extension of the midday break which in summer extends until mid-afternoon. Wind is also an environmental factor which influences flight: in several species wind s high speeds reduce flight s activities. However, afternoon peaks also occur in highly windy day.

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.

The studies described in this thesis investigate the role of indirect effects in invasion biology. The Introduction provides a brief overview of indirect effects and an outline of the thesis structure. The role of indirect effects in the context of invasion biology is addressed in an in-depth published literature review that comprises the second chapter, providing a theoretical background for the subsequent empirical studies. Chapters Three to Six are comprised of manuscripts that have been published or are under review or in press, which describe studies that investigate the importance of indirect effects in invasion biology using a model system consisting of the alien Asteraceae Senecio madagascariensis, a closelyrelated native, Senecio pinnatifolius, and the insect species with which they interact. Senecio madagascariensis and S. pinnatifolius occur in a similar geographic range in eastern Australia and these studies were conducted in mixed and pure populations of the two species. The herbivore and floral visitor assemblages of the two Senecio species at seven field sites in South-east Queensland were compared using sweep-net sampling, manual searching and floral visitor observation techniques. The floral visitor assemblages were similar between the two species, comprised largely of species of Syrphidae and the European honeybee, Apis mellifera. Herbivore assemblages, however, were highly variable both between species and between sites, with greater herbivore abundance and diversity recorded on the native S. pinnatifolius than its alien congener. The most commonly recorded herbivores were sap-sucking species such as Myridae. The magpie moth, Nyctemera amica was the most common folivore on both Senecio species and laboratory studies demonstrated a clear preference by ovipositing females and feeding larvae of this species for the native Senecio species, over the alien. Field surveys supported these findings, recording greater leaf damage on the native species than the invader. Herbivory levels were lower, rather than higher, in mixed populations than in pure populations, thus there was no evidence that the presence of one species enhanced herbivory in the other. Field pollination trials were conducted to determine whether competition for pollinators or facilitation of pollination occurred in mixed Senecio populations. The presence of the native S. pinnatifolius affected pollinator visitation rates to the alien Senecio; bee visits to S. madagascariensis were significantly reduced by the presence of S. pinnatifolius, whilst syrphid visits increased. However, altered visitation rates were not reflected in seed set. The presence of the alien species had no impact on pollinator visits to the native. Surprisingly, S. pinnatifolius seed set was higher in mixed populations than in pure populations. This might be due to abiotic factors, lower rates of herbivory at these sites or transfer of pollen between species resulting in the production of hybrid seed (if S. madagascariensis has greater male fitness). Hybridisation in the field was investigated using AFLP techniques. No mature hybrid plants were recorded in mixed populations, but hybrid seeds were produced by both species. Senecio pinnatifolius maternal parents produced higher numbers of hybrid seed than expected based on the relative frequencies of the two species, whilst hybridisation in S. madagascariensis was lower than expected. This may indicate greater male fitness of the invader. A range of complex indirect interactions can occur between invasive and native species, with these interactions having the potential to influence the success or failure of the invader and its impacts on co-occurring natives. The Discussion addresses the findings of the studies described here in the context of invasion biology theory.

The studies described in this thesis investigate the role of indirect effects in invasion biology. The Introduction provides a brief overview of indirect effects and an outline of the thesis structure. The role of indirect effects in the context of invasion biology is addressed in an in-depth published literature review that comprises the second chapter, providing a theoretical background for the subsequent empirical studies. Chapters Three to Six are comprised of manuscripts that have been published or are under review or in press, which describe studies that investigate the importance of indirect effects in invasion biology using a model system consisting of the alien Asteraceae Senecio madagascariensis, a closelyrelated native, Senecio pinnatifolius, and the insect species with which they interact. Senecio madagascariensis and S. pinnatifolius occur in a similar geographic range in eastern Australia and these studies were conducted in mixed and pure populations of the two species. The herbivore and floral visitor assemblages of the two Senecio species at seven field sites in South-east Queensland were compared using sweep-net sampling, manual searching and floral visitor observation techniques. The floral visitor assemblages were similar between the two species, comprised largely of species of Syrphidae and the European honeybee, Apis mellifera. Herbivore assemblages, however, were highly variable both between species and between sites, with greater herbivore abundance and diversity recorded on the native S. pinnatifolius than its alien congener. The most commonly recorded herbivores were sap-sucking species such as Myridae. The magpie moth, Nyctemera amica was the most common folivore on both Senecio species and laboratory studies demonstrated a clear preference by ovipositing females and feeding larvae of this species for the native Senecio species, over the alien. Field surveys supported these findings, recording greater leaf damage on the native species than the invader. Herbivory levels were lower, rather than higher, in mixed populations than in pure populations, thus there was no evidence that the presence of one species enhanced herbivory in the other. Field pollination trials were conducted to determine whether competition for pollinators or facilitation of pollination occurred in mixed Senecio populations. The presence of the native S. pinnatifolius affected pollinator visitation rates to the alien Senecio; bee visits to S. madagascariensis were significantly reduced by the presence of S. pinnatifolius, whilst syrphid visits increased. However, altered visitation rates were not reflected in seed set. The presence of the alien species had no impact on pollinator visits to the native. Surprisingly, S. pinnatifolius seed set was higher in mixed populations than in pure populations. This might be due to abiotic factors, lower rates of herbivory at these sites or transfer of pollen between species resulting in the production of hybrid seed (if S. madagascariensis has greater male fitness). Hybridisation in the field was investigated using AFLP techniques. No mature hybrid plants were recorded in mixed populations, but hybrid seeds were produced by both species. Senecio pinnatifolius maternal parents produced higher numbers of hybrid seed than expected based on the relative frequencies of the two species, whilst hybridisation in S. madagascariensis was lower than expected. This may indicate greater male fitness of the invader. A range of complex indirect interactions can occur between invasive and native species, with these interactions having the potential to influence the success or failure of the invader and its impacts on co-occurring natives. The Discussion addresses the findings of the studies described here in the context of invasion biology theory.

An outgroup can be defined as that which is perceived as different or dissimilar from oneself. The Interspecies Model of Prejudice (TIMP) predicts that negativity to human outgroups align with animal negativity. Human-centered and anti-egalitarian beliefs have shown to correlate with outgroup rejection. Experiencing a close relationship to nature has, on the other hand, been linked to outgroup acceptance. The aim of this study was to investigate the valuation of animal charismatic appeal overall, and as a function of outgroup acceptance - rejection. An online survey collected data on animal image ratings, attitude instruments, psychosocial and demographic factors from 231 high school senior students in the greater Stockholm area. Images of human-similar (anthropomorphic highcharismaticmammals) versus human-dissimilar (feral low-charismatic insects) animals were used to, respectively, predict the attitudes anthropocentrism, ethnocentrism and nature relatedness. Overall, mammals were rated significantly more positively than insects. The findings also suggest support for TIMP. It may be inferred that animal charismatic appeal is linked to individual differences in outgroup cognitions. Anthropocentrism and ethnocentrism associated negatively with general animal liking, and were predicted by insect negativity once significant covariates adjusted the models. Nature relatedness correlated positively with animal liking and was predicted by insect positivity. Our valuation of animal charisma may, thus, be linked to our appraisal of their more or less human-like qualities. Our valuations are proposed as underlied by identification mechanismsthat may guide our varying tendencies to divide the world into ‘us and them’. The findings could be informative of psychological factors involved in intergroup behaviors and environmental concerns.

Thesis (PhD)--University of Stellenbosch, 2005.
ENGLISH ABSTRACT: Climate sets range limits in many taxa, and as climate changes, the ranges that plants and animals occupy are altered. The responses of species to climate change involve either migration or local adaptation. An investigation of the local physiological adaptation shown by indigenous and alien arthropods to temperature acclimation formed the primary focus of this study. Increased environmental temperatures favour the establishment of alien species on Southern Ocean Islands. The first records of Porce/lio scaber Latreille, 1804 (Isopoda, Porcellionidae) and an Aphidius wasp species from Marion Island were documented here. The alien wasp was discovered in 2003 and had a current known distribution along the east coast of Marion Island. Both isopods and wasps were reproducing successfully on Marion Island. The wasp species is an aphid parasitoid and had been found mummifying the alien aphid Rhopalosiphum padi. These introductions highlighted the ongoing conflict between use and conservation on the Southern Ocean Islands. Despite considerable work on the upper and lower lethal limits of insects, several major taxa have received little attention. Here this issue was addressed and the lower and upper thermal tolerances and cold hardiness strategy of Antarciopsocus jeanneli Badonnel (Psocoptera: Elipsocidae) from sub-Antarctic Marion Island was investigated. A. jeanneli is freeze intolerant, and more specifically, moderately chill tolerant. Field fresh A. jeanne li had a mean supercooling point (SCP) of -11.1oC, whereas LTSO was -7.7°C, indicating pre-freeze mortality. A. jeanneli responded to acclimation: mean SCP increased from -IS.8°C at a treatment temperature ofO°C, to -7.3°C at ISOC. Investigations of the responses to acclimation of upper and lower lethal limits and limits to activity in insects have focussed primarily on Drosophila. Halmaeusa atriceps (Staphylinidae) was examined for thermal tolerance responses to acclimation, and seasonal acclimatization. In summer and winter, lower lethal temperatures of adults and larvae were c. -7.6 ± 0.03 and -11.1 ± 0.06 °C, respectively. Supercooling points (SCPs) were more variable, with winter SCPs of -S.4 ± 0.4 °C in larvae and -6.3 ± 0.8 °C in adults. The species appeared to be chill susceptible in summer and moderately freeze tolerant in winter, thus showing seasonal acclimatization. Critical thermal minima varied between -3.6 ± 0.2 and -0.6 ± 0.2 °C in larvae, and from -4.1 ± 0.1 to -0.8 ± 0.2 °C in adults. These findings were in keeping with the general pattern found in insects, although this species differed in several respects from others found on Marion Island. In this study the differential responses of indigenous and invasive springtails to temperature were explicitly examined in the context of the beneficial acclimation hypothesis (BAH) and its alternatives. In particular, the thermal acclimation responses of desiccation resistance, supercooling ability, lower and upper thermal limits were compared. Invasive springtails (Pogonognathellus jlavescens, Isotomurus palustris and Ceratophysella denticulata) did not display greater phenotypic flexibility than indigenous springtails (Cryptopygus antarcticus and Tullbergia bisetosa), but did perform better under high temperature conditions. Indigenous species, however, performed better under low temperature conditions. In most cases the BAH was not supported, or could not be distinguished from its alternatives. The prediction that invasive species will outperform indigenous species as climates on Southern Ocean Islands warm was supported. Because temperature plays such a large role in the distribution, abundance and physiological tolerances of invertebrates, microhabitat temperatures along an altitudinal gradient (0 to 800 m above sea level (asi)) were investigated over a two-year period on Marion Island. Mean microhabitat temperatures were comparable to those from previous studies for Southern Ocean Islands, and declined with increasing altitude. The 800 m asl site had the most severe microclimate (highest absolute maximum, lowest absolute minimum and the highest frequency of freeze-thaw cycles). Year one was substantially colder than year two, indicating that interannual variation in microclimate conditions could be responsible for substantial mortality amongst. invertebrate populations. Indeed, indigenous species were best able to tolerate the high incidence of low temperatures at high altitudes, whereas alien species appeared to be confined to lower altitudinal sites on Marion Island, possibly as a consequence of extreme low temperatures at higher altitudes.
AFRIKAANSE OPSOMMING: Klimaat is een van die grootste faktore wat die verpreiding en digthede van dier en plantspesies bepaal. Soos wat klimaatsverandering plaasvind, kan spesies migreer om stresvolle klimaatstoestande te vermy, of hulle kan aanpas by plaaslike omstandighede. Dit is die laasgenoemde opsie wat in hierdie tesis ondersoek was. Die opsporing van Porcellio scaber Latreille, 1804 (Isopoda Porcellionidae) en 'n Aphidius wesp van Marion Eiland word hier aangeteken. Die huidige verspreiding van houtluise in die omgewing van die Navorsingstasie dui daarop dat hulle die eiland waarskynlik vanaf Kaapstad in bou-materiaal bereik het. Die wesp is gedurende 2003 ontdek en is tans versprei langs die oostelike kuslyn van Marion Eiland. Beide hierdie spesies plant suksesvol voort op Marion Eiland. Die wesp spesie parasiteer die uitheemse plantluis Rhopalosiphum padi. Uitheemse muise en die inheemse kleinskedebek weier tot dusver om P. scaber te eet. Die ontdekking van twee nuwe uitheemse spesies dui weereens op die konflik tussen bewaring en benutting van die Suidsee Eilande. Ten spyte daarvan dat aansienlike aandag gewy is aan die hoë- en lae temperatuur toleransies van insekte, is daar talle taksa wat selde nagevors word. Dié toleransies is dus nagevors vir die boekluis Antarctopsocus jeanneli Badennel (Psocoptera: Elipsocidae) van Marion Eiland. Die spesie is vries vermydend, en meer spesifiek, matig verkoelingsbestand. Veldvars A. jeanneli het 'n gemiddelde superverkoelingspunt van - 11.1 °C gehad, en letale temperature (LTSO) van -7.7 °C, wat aandui dat individue vrek voordat hulle vnes, Hierdie spesie reageer op akklimasie: gemiddelde superverkoelingspunt het toegeneem van -15.8 °C na akklimasie by 0 °C tot -7.3 °C na akklimasie by 15 oe. Die effek van akklimasie op temperatuur toleransie in insekte het dusver meestalop Drosophila gefokus. Hier vors ons die effek van akklimasie op die temperatuur toleransie van Halmaeusa atriceps (Styphylynidae) na. In die somer en winter was die lae letale temperature van kewers en larwes onderskeidelik -7.6 ± 0.03 en -11.1 ± 0.06 °C. Superverkoelingspunte (SVP) het meer gevarieer, met SVP van -5.4 ± 0.4 °C in larwes en -6.3 ± 0.8 oe in kewers. Die spesie IS verkoelingsvatbaar in die somer en matig vriesbestand in die winter, wat dui op akklimatisasie in hierdie spesie. Kritiese termale minima het tussen -3.6 ± 0.2 en -0.6 ± 0.2 oe in larwes, en tussen -4.1 ± 0.1 tot -0.8 ± 0.2 oe in kewers gewissel. Hierdie spesie blyk dieselfde fisiologiese tendense wat in insekte te vinde is uit te beeld, maar verskil in verskeie opsigte van ander insekte op Marion Eiland. Hierdie studie het ook die verskillende reaksies van inheemse en uitheemse springsterte met betrekking tot temperatuur akklimasie bestudeer. Die voordelige-akklimasie hipotese en sy alternatiewe hipoteses is in terme van akklimasiereaksies tot desikkasie weerstand, superverkoeling en lae- en hoë temperatuur bestandheid in Marion Eiland springsterte getoets. Die uitheemse springsterte (Pogonognathellus jlavescens, Isotomurus cf palustris en Ceratophysella denticulata) het nie beter fenotipiese plastisiteit getoon as die inheemse spesies (Cryptopygus antarcticus en Tullbergia bisetosa) nie. Die inheemse spesies het egter beter gevaar onder lae-temperatuur toestande. Die voordeligeakklimasie hipotese ontvang nie veelondersteuning in die huidige studie nie, maar kon in sommige gevalle nie van die alternatiewe hipoteses onderskei word nie. Klimaatsverandering mag uitheemse spesies bevoordeel. Die rol wat temperatuur in die verspreiding en fisiologiese toleransies van invertebrate speel word lank reeds waardeer. Daarom vors hierdie studie die mikrohabitat temperature teen 'n gradient tussen seespieël en 800 m bo seespieël (m bs) oor 'n tydperk van twee jaar op Marion Eiland na. Gemiddelde temperature is vergelykbaar met die van vorige studies op Marion Eiland, en neem af soos wat hoogte bo seespieël toeneem. Die 800 m bs studie-gebied het die mees stresvolle mikrohabitat-toestande ondervind (die hoogste absolute maksimum, laagste absolute minimum temperature, en die meeste vries-ontdooi siklusse). Inheemse spesies op Marion Eiland toon hoër.toleransies tot lae temperature as uiheemse spesies, laasgenoemde kom slegs voor by laer hoogtes bo seespieël, waar ekstreme ternperatuur-toestande dalk minder volop is. Klimaatsverwarming mag egter tot 'n toename in ekstreme weerstoestande lei op Marion Eiland, wat aansienlike mortaliteit in invertebraat populasies kan veroorsaak.

The increasing international trade occurred in the last decades has raised the risk of introduction of invasive species. These are organisms introduced in new environments located out of their native area. Plants and insects represent the most common invasive species. Concerning insects, wood borers are the most important for forest ecosystems. Introductions of invasive alien species have strong ecological and economic effects on native fauna and their interception and eradication are prior goals. In the present work, the Asian longhorned beetle, Anoplophora glabripennis (Motschulsky), recently discovered in north Italy has been considered. This longhorned beetle is a threat for temperate forests of the northern hemisphere, accounting many infestation sites in Europe and North America. The rich literature, its biological characteristics and the wide distribution makes of A. glabripennis an appropriate model species. The thesis is divided into four main parts: the first (chapter 1) is an introduction about invasive species with special attention on A. glabripennis, providing the knowledge for understanding the following chapters. The second part (chapter 2) investigated the beetle introduction and spreading pathways in the infestation site through a dendrochronological study of the infested plants, identifying the oldest spot and the possible causes of introduction. The third part is composed of three chapters (3-4-5) focused on establishment into a new environment and adaptation to novel hosts, analysing the interactions between different environments and host preference. Chapter 3 studies insect phenology and life history in N Italy. Chapter 4 investigates the host-plant preferences. Effect of habitats and host plants is addressed in chapter 5, where the colonization failure of forest areas nearby the infestation is investigated. A last part (chapter 6) presents an analyses of the adult dispersal, developing an approach based on the probability of attack from an attacked host to an healthy one. The study contributes on the global knowledge of Anoplophora glabripennis, providing data from a new infestation area. Moreover, it looks for plausible explanation of species traits, such as the variation on host preference between populations. Finally, it is proposed a new approach to dispersal evaluation, which can be developed also on other invasive organisms.
L’incremento di scambi commerciali internazionali avvenuto ultimi decenni ha portato ad un aumento del rischio di introduzione di specie invasive, organismi che vengono introdotti in nuovi ambienti al di fuori del loro areale d’origine. Questi sono soprattutto piante ed insetti. Tra gli insetti, di particolare interesse forestale risultano essere le specie xilofaghe. Queste introduzioni hanno gravi effetti economici ed ecologici, ed è un obiettivo prioritario l’intercettazione e l’eradicazione di queste specie nei siti di introduzione. Nel presente lavoro viene presa in considerazione il coleottero cerambicide di origine asiatica Anoplophora glabripennis (Motschulsky). Questo cerambicide rappresenta una grande minaccia per le foreste temperate dell’emisfero boreale, e ricorre in molte aree di infestazione in Europa e Nord America. La consistente bibliografia esistente, la sua biologia e la sua accezione cosmopolita ne fanno una specie modello estremamente interessante. Un’area di infestazione presente in Nord Italia (Regione Veneto) è stato il sito di studio della specie. La tesi si struttura in quattro parti. La prima (capitolo 1) è un’introduzione sulle specie invasive e su A. glabripennis in particolare, fornendo le conoscenze necessarie alla comprensione dei capitoli successivi. La seconda parte (capitolo 2) presenta un’analisi delle dinamiche di introduzione di A. glabripennis tramite uno studio dendrocronologico delle piante colpite, che identifica i punti di più antica datazione e ne spiega la causa dell’introduzione. La terza parte è costituita da tre capitoli (3-4-5) che considerano l’insediamento di A. glabripennis in un nuovo ambiente e l’adattamento a nuove piante ospiti, investigando inoltre quali sono gli effetti di diversi ambienti e ospiti. Il capitolo 3 indaga la fenologia e biologia di A. glabripennis in nord Italia; il capitolo 4 tratta delle preferenze di A. glabripennis a le diverse specie ospiti; il capitolo 5 indaga infine l’interazione tra ambiente e pianta ospite, ricercando le cause della mancata colonizzazione delle aree forestali confinanti l’infestazione considerata nello studio. La quarta e ultima parte presenta un’analisi delle dinamiche di dispersione di A. glabripennis negli ambienti di neocolonizzazione, sviluppando un approccio basato sulla probabilità di attacco di un nuovo ospite in relazione alla distanza da una pianta colpita. Nel complesso, lo studio contribuisce alle conoscenze sulla specie, fornendo dati provenienti da una nuova area di infestazione. Non solo, ricerca anche spiegazioni ad alcune caratteristiche di A. glabripennis, quali la scarsa attitudine alla colonizzazione di aree boschive e la variabilità intrinseca nella scelta delle specie ospiti. Viene introdotto, infine, un nuovo approccio alla stima di dispersione della specie che potrà essere applicato anche ad altri organismi invasivi.

De nouveaux gisements à ambre et à végétaux ont été découverts dans les terrains
albiens et cénomaniens de Charente-Maritime (France). L'un d'eux, daté de l'Albien, constitue l'un des plus anciens mais aussi l'un des plus importants gisements d'ambre fossilifère du Crétacé, compte tenu de la richesse et de la diversité des inclusions répertoriées. Les insectes et les arthropodes sont les plus nombreux, mais quelques restes de vertébrés (plume, peau de reptile) et des fragments végétaux sont également signalés. La singularité de cet ambre est d'avoir préservé une abondante faune d'arthropodes vivant au niveau de la litière du sol, alors que l'essentiel des inclusions représente généralement le biotope vivant le long du tronc ou des branches de l'arbre producteur de résine. La confrontation d'analyses taphonomiques, xylologiques et physico-chimiques permet de discuter la source botanique probable de cet ambre.
Quelques insectes particulièrement significatifs pour la compréhension de l'histoire
évolutive de leur groupe, ou bien informatifs d'un point de vue paléoenvironnemental ou paléobiogéographique, font l'objet d'une étude systématique détaillée. Des informations complémentaires, d'ordre paléoécologique et paléoclimatique, sont apportées par les nombreux végétaux associés dans les gisements sous forme de bois ou de feuilles. Une reconstitution régionale des écosystèmes terrestres côtiers médio-crétacés est proposée, via l'analyse sédimentologique des milieux de dépôt et les informations paléoécologiques fournies par ces assemblages fossiles. Ces gisements contribuent à une meilleure connaissance des biotopes côtiers du Crétacé, période cruciale pendant laquelle la co-évolution des insectes et des plantes à fleurs a constitué les prémices de nos écosystèmes actuels.

The increased complexity of transport networks, the augmented demand of commodities, and the consequent enhanced goods flows worldwide intensify the likelihood of alien species invasions. Allochthonous invasive species are the second leading driver of species extinctions and pose serious threats to ecosystem services, economies, and human health and wellbeing. Terrestrial arthropods, and particularly insects, are a large part of the problems generated by alien species. To develop effective strategies to prevent and manage biological invasions, information regarding pathways of introduction and biology and behavior of introduced species should be gathered. In my thesis, I attempted to quantify the entomological allodiversity (i.e. the diversity of alien insects) in Tuscany: I compiled a dataset and compared my results with those from datasets of Italian and European allodiversity. During field surveys, Gonipterus scutellatus complex, a quarantine pest weevil damaging Eucalyptus spp., has been detected for the first time in Tuscany, along with other pests of eucalypts. Then, I focused my research on the study of the pathways of introduction, evaluating the risk of introduction on pests (e.g. Thrips palmi) as contaminants of fresh-cut flowers. Curculionidae (bark beetles and weevils) were the target species of my research. I assessed the role of nurseries and horticultural activity in introducing bark beetles, and investigated some behavioral aspects of the red palm weevil, Rhynchophorus ferrugineus, a pest of palm spreading in Tuscany. In particular, in R. ferrugineus I analyzed behaviors whose knowledge is necessary for the application of new management techniques, such as sterile insect technique and the biocontrol with microbial agents. I also investigated female oviposition preferences and male role in indicating a good site for laying eggs. The results show that Tuscany is particularly exposed, as the entire Italy, to biological invasions of arthropods. Notwithstanding this, knowledge of allochthonous species assemblages, such as eucalyptus species and the invertebrate they host, is scanty. The study of pathways is crucial to tackling invasions. Pests contaminating commodities are difficult to detect and information about their deliveries (e.g. origin, dimensions, and packaging procedures) are precious to better focus the inspection effort at political borders. The first report in Tuscany of Ambrosiodmus rubricollis confirms that ornamental nurseries and horticultural industry are gateways for allochthonous bark beetles, due to the their resistance to common phytosanitary treatments, which make nurseries uncomfortable for the survival of phytophagous and other insects occupying flowers, fronds, leaves, and external surfaces of plants. In conclusion, my results highlight the importance of biological and behavioral studies to develop and improve the available tools for the management of biological invasions. In fact, the model species R. ferrugineus shows a complex mating system, which is compatible with the use of new management techniques, despite the need of further studies before their application.

碩士
國立臺灣大學
昆蟲學研究所
97
Pet insects’ market in Taiwan is expanding now, more alien pet insects has been imported to Taiwan in legal and illegal ways. From 2000 to now, the rapid development of alien pet insects is even more alarming. In 2005, there are only 5 insect stores in Taiwan, up to now it increases to 85. In many aquarium shops or traditional pet shops, or even the vendors in the streets, this situation makes the pet insect purchase easily. According to the survey, there are 189 species of pet insects in Taiwan, and 172 species are stag-beetle (Lucanidae) or rhinocero beetles (Scarabaeidae). Most of them are from Japan and South Asia. The damage of invading species to the ecosystem of invaded area has many related research. Finding a balance between the protection of the ecosystem of Taiwan and the demand of the market is an important issue. In this paper, based on quarantine pest risk analysis to assess the potential risks of alien insects, and that it will serve as a viable basis for effective management approach. The results indicates more than 31 species are rank to high risk species. And the results are also proposed that Bureau of Animal and Plant Health Inspection and Quarantine and other relevant units may do not permit these high risk species import and sale or follow the example of Japan set the sunset provisions. Otherwise, this research will serve as a viable basis for effective management approach.

A new predictive modelling technique called the fuzzy envelope model (FEM) is introduced. The technique can be used to predict potential distributions of organisms using presence-only locality records and a set of environmental predictor variables. FEM uses fuzzy logic to classify a set of predictor variable maps based on the values associated with presence records and combines the results to produce a potential distribution map for a target species. This technique represents several refinements of the envelope approach used in the BIOCLIM modelling package. These refinements are related to the way in which FEMs deal with uncertainty, the way in which this uncertainty is represented in the resultant potential distribution maps, and the way that these maps can be interpreted and applied. To illustrate its potential use in biogeographical studies, FEM was applied to predicting the potential distribution of three invasive alien plant species (Lantana camara L., Ricinus communis L. and Solanum mauritianum Scop.), and three native cicada species (Capicada decora Germar, Platypleura deusta Thun. and P. capensis L.) in South Africa, Lesotho and Swaziland. These models were quantitatively compared with models produced by means of the algorithm used in the BIOCLIM modelling package, which is referred to as a crisp envelope model (the CEM design). The average performance of models of the FEM design was consistently higher than those of the CEM design. There were significant differences in model performance among species but there was no significant interaction between model design and species. The average maximum kappa value ranged from 0.70 to 0.90 for FEM design and from 0.57 to 0.89 for the CEM design, which can be described as 'good' to 'excellent' using published ranges of agreement for the kappa statistic. This technique can be used to predict species' potential distributions that could be used for identifying regions at risk from invasion by alien species. These predictions could also be used in conservation planning in the case of native species.

The conservative method of host specificity testing dictates that a potential biological control agent which shows polyphagous behaviour in the laboratory will be rejected, even though in a natural situation it may be monophagous or nearly so. To distinguish one from the other the performance of eucalyptus weevil, (Gonipterus scutellatus) was tested on 14 Eucalyptus and one Syzygium species in the laboratory, and the field. The weevil revealed different levels of polyphagy, depending on how the host plants were presented; as cut leaves, bouquets or sleeved-branches; or in choice or no-choice combinations. However, the fundamental host range was broader than the realized host range. Eucalyptus smithii and E. urophylla were the most preferred hosts (contrary to the literature), while E. saligna and Syzygium myrtifolia were immune to feeding and oviposition. Nevertheless, adult feeding and oviposition was more selective in the field, and the larvae are less discriminating than the adults. Finally, the weevil is shown to have a narrow host range within two sections of the subgenus Eucalyptus, sufficiently restricted if it was ever to be considered as a biocontrol agent.