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Sievert, Thorbjörn. "Behavioural responses of mice to predator odour components." Thesis, Linköpings universitet, Biologi, 2015. http://urn.kb.se/resolve?urn=urn:nbn:se:liu:diva-119355.
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Having means to detect and avoid potential predators is a necessity for prey species. Most mammalian prey species are able to detect odours emitted by predators and to adapt their behaviour accordingly. These odour cues are therefore considered to act as semiochemicals. Predator odours consist of several dozen different odourants. In order to assess if single odourants elicit aversive behavioural reactions, predator-naïve CD-1 mice were presented with six odourants which are part of body-borne odours of different mammalian predator species. A two-compartment chamber was used in order to assess place-preference, motor activity and faecal excretions when the animals were simultaneously presented with a predator odourant and a blank control. Further trials were performed to assess whether the odourant concentrations had an influence on the behaviours. The only odourant that elicited a significant aversion was 3-methyl-1-butanethiol, a compound found in the anal gland secretion of skunks, when presented at a factor of 100 above the olfactory detection threshold of mice. Two other concentrations of 3-methyl-1-butanethiol did not elicit significant behavioural changes. Based on the present study, only one out of six selected predator odourants elicited a significant aversive response in CD-1 mice. This suggests that more than one odour component, or perhaps even the full mixture of odourants, may be necessary for CD-1 mice to respond to a predator odour with aversive behaviour.
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Hay, Alexandra Morag. "Foraging behaviour of the ruffe (Gymnocephalus cernuus) and predator avoidance by freshwater isopod Asellus aquaticus : implications for predator-prey interactions." Thesis, University of Glasgow, 1999. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.312702.
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Borner, Karoline. "Influence of turbidity on social structure in guppies, Poecilia reticulata." Doctoral thesis, Humboldt-Universität zu Berlin, Lebenswissenschaftliche Fakultät, 2016. http://dx.doi.org/10.18452/17622.
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Umweltveränderungen kommen natürlicherweise vor und viele Spezies waren im Laufe ihrer Evolutionsgeschichte davon betroffen. Durch die Aktivitäten des Menschen jedoch finden diese in höherer Geschwindigkeit und größerem Umfang statt und stellen so für viele Spezies eine neue Herausforderung dar. Einen großen Einfluss auf die Umwelt nimmt der Mensch durch Verschmutzung, welche zu Veränderungen der Physiologie der Organismen und deren Verhalten führen und damit Einfluss auf die Populationsdynamik und letztendlich auf die Biodiversität haben kann. In meiner Dissertation untersuchte ich den Einfluss durch Bergbau ausgelöster Trübung auf das Verhalten und die soziale Struktur des Guppys. Er nutzt soziale Interaktionen für eine höhere Effizienz bei der Nahrungssuche und Räubervermeidung. Die Nutzung sei-nes dafür eingesetzten Sehsinns ist bei Trübung stark eingeschränkt. Ich untersuchte die Reaktion Trübung unerfahrener Fische aus Labor und Feld auf Trübung. Es zeigte sich, dass beide ihre sozialen Interaktionen in trübem Wasser verringerten. Eine zusätzliche Markow-Ketten-Analyse ergab aber auch, dass Laborfische Kontakte zu bestimmten In-dividuen der Gruppe verstärkten und Feldfische ihre initiierten Kontakte behielten. An-schließend studierte ich den Unterschied der sozialen Struktur Trübung erfahrener und - unerfahrener Fische. Trübung erfahrene Fische erhöhten die Gesamtzahl der Interaktio-nen, reduzierten jedoch die Anzahl der initiierten Kontakte im Gegensatz zu unerfahre-nen Fischen. Diese Strukturänderung, vermute ich, erhöht den Zusammenhalt und damit den In-formationsfluss im Schwarm. Die Ergebnisse von Folgeversuchen, nämlich der Erhalt der Paarungsanzahl und die effektivere Vermeidung einer Räuberattrappe bei Trübung er-fahrenen Fischen, unterstützen diese Vermutung. Die Arbeit zeigt, dass Guppys in der Lage sind, sich durch Änderung Ihrer sozialen Struktur an trübe Verhältnisse anzupas-sen. Dies könnte auch Einfluss auf ihre Populationsstruktur haben.Most species have been subjected to environmental changes during their evolutionary history. However, due to human activity, environmental changes are currently occurring at higher speeds and on a greater scale, presenting new challenges for many species. Pollution, as a major type of human-induced environmental change, may not only affect physiology but also behaviour, thereby affecting population dynamics and consequently biodiversity. The topic of my dissertation is the effect of turbidity from quarrying on the behaviour and social association pattern of the guppy (Poecilia reticulata). Turbidity impairs the fish’s ability to use visual cues during social interactions, which in turn helps increases efficiency of foraging and avoiding predators. I investigated the initial re-sponse of guppies to turbidity and subsequently tested whether turbidity-experienced vs turbidity-inexperienced populations differ in their social association patterns and how they cope with ecological challenges. Both lab-reared and wild-caught guppies that were inexperienced with turbidity reduced social associations in turbid water in con-trast to turbidity-experienced fish. A Markov chain analysis revealed that lab-reared guppies increased associations with particular neighbours. Similarly, wild-caught gup-pies maintained the number of initiated associations under turbid conditions. The in-crease in non-initiated associations suggests a stronger connectivity within the shoal, leading to higher information transmission in a poor visual environment. Additional results showed that this altered social structure enabled turbidity-experienced fish to maintain the frequency of mating attempts in turbidity and to avoid predation risk. This suggests that guppies have the ability to adjust to turbidity, but with major changes in their social structure, which might have an impact on population dynamics.
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Nelson, Erik Healy. "Population consequences of predator avoidance behavior in the pea aphid /." For electronic version search Digital dissertations database. Restricted to UC campuses. Access is free to UC campus dissertations, 2003. http://uclibs.org/PID/11984.
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Hörnfeldt, Birger. "Cycles of voles, predators, and alternative prey in boreal Sweden." Doctoral thesis, Umeå universitet, Ekologi och geovetenskap, 1991. http://urn.kb.se/resolve?urn=urn:nbn:se:umu:diva-100711.
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Bank voles, grey-sided voles, and field voles had synchronous 3-4 year density cycles with variable amplitudes which averaged about 200-fold in each species. Cycles of vole predators (red fox and Tengmalm's owl), and their (foxes') alternative prey (mountain hare and forest grouse) lagged behind the vole cycles. The nomadic Tengmalm's owl responded with a very rapid and strong numerical increase to the initial cyclic summer increase of voles (the owl’s staple food). Owl breeding densities in the springs were highly correlated with vole supply in the previous autumns. This suggested that the number of breeding owls was largely determined in the autumn at the time of the owl's nomadic migrations, and that immigration was crucial for the rapid rise in owl numbers. The owl's numerical response was reinforced by the laying of earlier and larger clutches when food was plentiful. In addition, the owl has an early maturation at one year of age. The transition between subsequent vole cycles was characterized by a distinct shift in rate of change in numbers from low to high or markedly higher values in both summer and winter. Regulation increased progressively throughout the cycle since the rate of change decreased continuously in the summers. Moreover, there was a similar decrease of the rate of change in winter. Rate of change was delayed density-dependent. The delayed density-dependence had an 8 month time-lag in the summers and a 4 month time-lag in the winters relative to the density in previous autumns and springs, respectively. These findings suggest that vole cycles are likely to be generated by a time-lag mechanism. On theoretical grounds, it has been found that a delayed density- dependence of population growth rate with a 9 month time-lag caused stable limit cycles with a period between 3 and 4 years. Some mechanisms for the delayed density-dependence are suggested and discussed. The mechanisms are assumed to be related to remaining effects of vole populations past interactions with predators, food supplies, and/or diseases. Unlike the other voles, the bank vole had regular and distinct seasonal declines in density over winter. These declines are proposed to be due to predation, mainly by Tengmalm's owl. Supranivean foraging for epiphytic tree lichens and conifer seeds most likely explains why this species was frequently taken by the owl under snow-rich conditions. The alternative prey hypothesis predicts that a reduction of predator numbers should increase the number of alternative prey. Alternative prey should be less effectively synchronized to the vole cycle by predation at declining and low vole (main prey) densities; they may also lose their 3-4 year cyclicity. The appearance of sarcoptic mange among foxes in northern Sweden in the mid 1970s provided an opportunity to "test" these ideas, and these were found to be supported. In areas with highest mange infection rates, foxes declined markedly from the late 1970s to mid 1980s, whereas hare numbers rose rapidly and appeared non-cyclic.Diss. (sammanfattning) Umeå : Umeå universitet, 1991, härtill 7 uppsatser
digitalisering@umu
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Dempsey, Brian L. "Predator-Avoidance of Larval Black-bellied Salamanders (Desmognathus quadramaculatus) in Response to Cues from Native and Nonnative Salmonids." Digital Commons @ East Tennessee State University, 2020. https://dc.etsu.edu/etd/3824.
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The introduction of nonnative salmonids into Southern Appalachia may pose a threat to resident salamander populations. In recent years, the stocking and encroachment of rainbow trout (Oncorhynchus mykiss) into headwaters where the black-bellied salamander (Desmognathus quadramaculatus) and brook trout (Salvelinus fontinalis) naturally coexist has raised concerns. In aquatic prey, predator-avoidance responses are primarily influenced through the detection of chemical cues released from predators. The objective of this study was to determine how co-occurrence with a predator influences black-bellied salamander predator recognition behavior. To evaluate this, salamander activity metrics (general activity, number of movements, and latency to move) were recorded before and after exposure to either native trout predator cue (brook), introduced trout predator cue (rainbow), or conditioned tap water (control). Larvae were collected from different streams based on their trout predator assemblage with larvae coming from brook, rainbow, rainbow/brook, and no trout stream reaches. Our results show that larvae that co-occur with trout reduced their activity when exposed to brook trout predator cue, but their response to rainbow trout predator cue depended on their previous co-occurrence. Larvae from areas with only brook trout exhibited a weak predator-avoidance when exposed to rainbow trout predator cue. A follow-up test to determine the influence of alarm cue on predator response in these larvae indicated that the alarm cue enhanced the response to the rainbow trout predator.
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Sommers, Pacifica. "Interacting Effects of Predation and Competition in the Field and in Theory." Diss., The University of Arizona, 2015. http://hdl.handle.net/10150/595999.
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The principle of competitive exclusion holds that the strongest competitor for a single resource can exclude other species. Yet in many systems, more similar species appear to stably coexist than the small number of limiting resources. Understanding how and when similar species can stably coexist has taken on new urgency in managing biological invasions and their ecological impacts. Recent theoretical advances emphasize the importance of predators in determining coexistence. The effects of predators, however, can be mediated by behavioral changes induced in their prey as well as by their lethality. In this dissertation, I ask how considering multiple trophic levels changes our understanding of how a grass invasion (Pennisetum ciliare) affects species diversity and dynamics in southeastern Arizona. In considering interactions with plant consumers, and with the predators of those consumers, this research reveals more general ecological processes that determine species diversity across biological communities. I first present evidence from a grass removal experiment in the field that shows increased emergence and short-term survival of native perennial plants without grass. This is consistent with Pennisetum ciliare causing the observed concurrent decline in native plant abundance following invasion. I then present results from greenhouse and field studies consistent with that suppression of native plants being driven primarily through resource competition rather than increased rodent granivory. Granivorous rodents do not solely function as consumers, however, because they cache their harvested seeds in shallow scatter-hoards, from which seeds can germinate. Rodents thus act also as seed dispersers in a context-dependent mutualism. The primary granivores in areas invaded by Pennisetum ciliare are pocket mice (genus Chaetodipus), which have a well-studied tendency to concentrate their activity under plant cover to avoid predation by owls. Because the dense canopy of the grass may provide safer refuge, I hypothesized the pocket mice may be directly dispersing native seeds closer to the base of the invasive grass. Such a behavior could increase the competitive effect of the grass on native plant species, further driving the impacts of the invasion. By offering experimental seeds dusted in fluorescent powder and tracking where the seeds were cached, I show that rodents do preferentially cache experimental seeds under the grass. This dispersal interaction may be more general to plant interactions with seed-caching rodents across semi-arid regions that are experiencing plant invasions. Finally, I ask how the predator avoidance behavior exhibited by these rodents affects their ability to coexist with one another. Not only could their diversity affect that of the plant community, but the effects of plant invasions can cascade through other trophic levels. Theoretical understanding of how similar predator avoidance strategy alters coexistence had not yet been developed, however. Instead of a field study, therefore, I modified a general consumer-resource model with three trophic levels to ask whether avoidance behavior by the middle trophic level alters the ability of those species to coexist. I found that more effective avoidance behavior, or greater safety for less cost, increased the importance of resource partitioning in determining overall niche overlap. Lowering niche overlap between two species promotes their coexistence in the sense that their average fitness can be more different and still permit coexistence. These results provide novel understanding of behavioral modifications to population dynamics in multi-trophic coexistence theory applicable to this invasion and more broadly.
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Cushing, Paula Elizabeth. "A study of disturbance behaviors in Uloborus glomosus (Araneae; Uloboridae) as possible predator avoidance strategies." Thesis, This resource online, 1988. http://scholar.lib.vt.edu/theses/available/etd-10022008-063248/.
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McNeill, Myndee. "Predation Avoidance Response Behaviors, Oviposition and Distribution of the Intertidal Gastropod Lirularia succincta." Thesis, University of Oregon, 2011. http://hdl.handle.net/1794/11491.
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xiii, 141 p. : ill. (some col.)The small trochid gastropod
Committee in charge: Dr. Craig M. Young, Chair; Dr. Richard B. Emlet, Member; Dr. Alan L. Shanks, Member
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Maxey, Claire Angela. "Home Is Where The Food Is: Predator Avoidance Behaviors in the Black-tailed Prairie Dog (Cynomys Ludovicianus)." Thesis, The University of Arizona, 2014. http://hdl.handle.net/10150/321880.
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Coleman, Benjamin Thomas. "Spatial and temporal determinants of samango monkey (Cercopithecus mitis erythrarchus) resource acquisition and predation avoidance behaviour." Thesis, Durham University, 2013. http://etheses.dur.ac.uk/7342/.
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Food acquisition and predator avoidance are principal components of the survival strategies of all primates. However, for primates, maximising food acquisition whilst minimising predation risk is often impossible. This leads to the existence of the foraging/risk trade-off, a mechanism fundamental in shaping life histories, species interactions and ultimately community assemblage. The principal aim of this study was to investigate how samango monkeys (Cercopithecus mitis erythrarchus) strategically balance the foraging/risk trade-off when exposed to spatially and temporally varying resources and risk. Data were collected on a habituated group of samango monkeys over a 12 months observational period at the Lajuma Environmental Research Centre, South Africa. The focal group are part of a population near the southerly limit of the most southerly ranging African, primarily arboreal, monkey species. A biogeographical approach was also used, utilising ecological data from 12 different populations of C. mitis from a number of field sites across the species’ distribution. Cold, dry winter periods were associated with increased time spent feeding and decreased in time spent resting. During winter months the samangos supplement their diet with foliar material, most likely due to the increased energetic requirements of maintaining body temperature. On a geographical scale, southern populations of samango have significantly more fruit in their diet than their more equatorial relations; whilst the opposite pattern is apparent involving the amount of animal matter consumed. On a spatial scale resources appear to be less important in determining samango ranging behaviour than the risk of predation. The study group actively avoid areas of perceived eagle predation risk, even though resources, such as food, are available in those areas. Similarly, the samangos increase time spent vigilant when in areas of high perceived eagle predation risk, but environmental factors such as visibility or food availability have little effect on vigilance. The findings of this study indicate that a population at the edge of their species’ ecological tolerance are forced to considerably adapt behaviourally to seasonally and spatially varying resources and risk. In particular, great effort is put into avoiding predation risk; by avoiding high risk areas and maintaining an adequate level of vigilance. All of this must be achieved whilst combating rival groups and maintaining a territory, ensuring adequate food can be foraged and ensuring the successful raising of the next generation.
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Storsberg, Silke [Verfasser]. "How predator odors affect avoidance behavior of laboratory and wild rat strains / Silke Diana Ariadne Margarete Else Annemarie Storsberg." Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2018. http://d-nb.info/1219936952/34.
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Storsberg, Silke Diana Ariadne Margarete Else Annemarie [Verfasser]. "How predator odors affect avoidance behavior of laboratory and wild rat strains / Silke Diana Ariadne Margarete Else Annemarie Storsberg." Magdeburg : Universitätsbibliothek Otto-von-Guericke-Universität, 2018. http://d-nb.info/1219936952/34.
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Shabani, Shkelzen. "The Role of Chemical Senses in Predation, Risk Assessment, and Social Behavior of Spiny Lobsters." Digital Archive @ GSU, 2008. http://digitalarchive.gsu.edu/biology_diss/44.
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Chemical senses play a critical role in predator-prey and social interactions of many animals. Predators often evoke adaptive escape responses by prey, one of which is the release of chemicals that induce adaptive avoidance behaviors from both predators and conspecifics. I explore the use of chemicals in predator-prey and social interactions, using a crustacean model system, the spiny lobster. As predators, spiny lobsters are opportunistic, polyphagous feeders, and they rely heavily on their chemical senses during feeding. Some of their potential prey deter attacks through chemical defenses that act through the spiny lobsters’ chemical senses. An example of this is sea hares, Aplysia californica, which secrete an ink when vigorously attacked by sympatric spiny lobsters, Panulirus interruptus. I show that that this ink defends sea hares from spiny lobsters through several mechanisms that include phagomimicry, sensory disruption, and deterrence, and that the ink’s efficacy is enhanced by its naturally high acidity. As prey, spiny lobsters rely heavily on their chemical senses to assess risk from predators. One way to assess risk of predation is through ‘alarm cues’, which are injury-related chemicals. I show that injured Caribbean spiny lobsters, Panulirus argus, release alarm cues in their hemolymph, and that nearby conspecifics detect these cues using olfaction. Hemolymph from conspecifics induces primarily alarm behavior in the form of retreat, sheltering, and suppression of appetitive responses. In contrast, hemolymph from heterospecifics, depending on phylogenetic relatedness, induces either mixed alarm and appetitive behaviors or primarily appetitive behaviors. Spiny lobsters also use chemical cues to assess risk during social interactions with conspecific. I show that spiny lobsters use urine-borne chemical signals and agonistic behaviors to communicate social status and that these chemical signals are detected exclusively by the olfactory pathway. Dominant animals increase urine release during social interactions, whereas subordinates do not. Experimental prevention of urine release during interactions causes an increase in agonism, but this increase is abolished when urine of dominants is reintroduced. My findings lay the foundation for neuroethological studies of risk-assessment systems mediated by intraspecific chemical cues.
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Falkowski, Marcin. "The spectral and temporal properties of fiddler crab photoreceptors in the context of predator avoidance." Phd thesis, 2017. http://hdl.handle.net/1885/144592.
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The ability to detect and effectively escape from predators is
critical to an animal's survival, and the ability to do so
effectively depends on its sensory system. Vision is the dominant
if not sole sensory system fiddler crabs use for predator
avoidance. In this thesis I investigate the photoreceptor
properties of two fiddler crab species, Uca vomeris and Uca
dampieri, and their escape behaviour under field conditions with
the aim to further our knowledge of how these crabs use visual
information to organise their escape behaviour.
In an attempt to elucidate the spectral sensitivities of the
crabs' photoreceptors, intracellular electrophysiological
recordings were performed and are presented in Chapter 2.
Temporal resolution of their visual system was investigated using
both intracellular recordings and electroretinograms (ERGs) and
presented in Chapter 3. The following two chapters present the
results of behavioural experiments into the effect of the
predator's elevation in the crabs' visual field on two stages of
the crabs' predator avoidance response: the run home stage
(Chapter 4) and the burrow descent stage (Chapter 5).
I found that both species of fiddler crabs have a UV-sensitive
photopigment, plus one or two photopigments with a peak
sensitivity in the blue part of the spectrum (400-500 nm). Their
temporal resolution, measured as critical flicker fusion
frequency (CFF), was similar to other non-flying animals at
around 70 Hz. When measured as integration time and time-to-peak,
however, their temporal resolution was very high, comparable even
to flying animals. The behavioural experiments revealed that at
the run home stage, the crabs perceive objects changing in
elevation as most dangerous. Additionally, when far from the
burrow they respond earlier to objects appearing low in the
visual field, whereas when close to their burrow, such as at the
stage of the burrow descent, they are more sensitive to objects
that are seen high in the visual field.
These investigations into the visual system and into predator
avoidance behaviours of fiddler crabs move us closer to
establishing them as a model system where we understand the first
stage of sensory processing, which in turn will allow us to
investigate how further neural processing leads to the functional
behavioural output that can be observed in the field.
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Pai, Jen-Hui, and 白任暉. "The Interaction of High Temperature and UV-B Radiation on Tadpole Development, Morphology and Predator Avoidance Behaviour." Thesis, 2016. http://ndltd.ncl.edu.tw/handle/06696938348372207300.
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碩士國立臺灣大學
生態學與演化生物學研究所
104
Amphibians are ectotherms that reside in both aquatic and terrestrial systems which make them extremely sensitive to changes in their environment, and past research has shown that global climate change has contributed substantially to the recent global amphibian decline. Although there are plentiful research on the effects of temperature or UV-B radiation on amphibian development, morphology, and behaviour, respectively, there has been very little research on the interaction of high temperature and UV-B on amphibians. The aim of this study is to determine the interaction effects of high temperature and UV-B, under a global warming scenario, on tadpole development and morphology, as well as to determine how these effects would impact the predator avoidance behaviour of tadpoles. I examined the independent and interaction effects of temperature and UV-B on various developmental and morphological traits of the LaTouche''s frog (Hylarana latouchii) by randomly distributing the egg masses into 4 different treatment groups in a 2 x 2 factorial combination of high and low temperature and UV-B. The developmental and morphological traits of the embryos/tadpoles were recorded and analyzed from Gosner stage 9 (G9) to Gosner stage 32 (G32). I also examined the predator avoidance response of tadpoles that have successfully reached G32 by measuring burst swimming speed. The results indicated that high UV-B had negatively affected the majority of tadpole traits including increased mortality and abnormalities, decreased longevity, and decreased tadpole overall size and width (including total length, body length, body width, and tail muscle width). This may be due to the DNA damage accumulated due to prolonged UV-B exposure. High temperature, on the other hand, had only decrease longevity and increased tail muscle width of tadpoles. The decrease in longevity revealed that slight increase in temperature may have a direct negative effect on tadpole development. Moreover, there was an interaction effect of temperature and UV-B. In this study, high temperature was ameliorating the negative effects that UV-B was exerting on tadpole. Also, morphological abnormality and damage did seem to carry over and significantly decreased burst swimming performance of tadpoles which may lead to increase in predation and decrease foraging capabilities. This study shows that under a global warming scenario, UV-B radiation is a much higher stressor to amphibian species than temperature and an incremental increase in temperature, within the species’ thermal range, may help ameliorate the morphological damages caused by UV-B.
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König, Ulrike [Verfasser]. "A life less ordinary : foraging behaviour and predator avoidance in young-of-the-year perch / vorgelegt von Ulrike König." 2009. http://d-nb.info/99580754X/34.
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Smolka, Jochen. "Sampling Visual Space: Topography, colour vision and visually guided predator avoidance in fiddler crabs (Uca vomeris)." Phd thesis, 2009. http://hdl.handle.net/1885/7107.
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Many animals use vision to guide their behaviour and to collect relevant information about their environment. The diversity of visual environments and of visually guided tasks has led to a large variety of specialisations of eyes and visual systems. Our knowledge, however, about how the anatomical and physiological properties of eyes and the behavioural strategies of animals relate to the visual signals that are important to them in their natural environment, is extremely limited. In this thesis, I make use of optical, physiological and behavioural analyses to reconstruct the flow of visual information that the fiddler crab Uca vomeris experiences during its daily life on the mudflat. I present a detailed analysis of the first stage of visual processing, the sampling by the ommatidial array of the crabs' compound eye and demonstrate how regional specialisations of optical and sampling resolution reflect the information content and behavioural relevance of different parts of the visual field. Having developed the first intracellular electrophysiological preparation in fiddler crabs, I then examine the spectral sensitivities of photoreceptors - the basis for colour vision. I show that the crabs possess an unusual trichromatic colour vision system featuring a UV-sensitive and a variety of short-wavelength receptor types based on the coexpression of two short-wavelength sensitive pigments. Finally, the natural visual signals that predatory and non-predatory birds present to fiddler crabs are described. The visual cues the crabs use when deciding whether and when to respond to these potential predators are analysed and compared to those used in dummy predator experiments. The crabs use a decision criterion that combines multiple visual cues - including retinal speed, elevation and visual flicker. Neither of these cues accurately predicts risk, but together they reflect the statistical properties of the natural signals the crabs experience. The complex interactions between the design of the crabs' visual system, the stimuli they experience in their natural context and their behaviour demonstrate that neither of them can be understood without knowledge of the other two.Research School of Biological Sciences (RSBS, now RSB), and the Australian National University for providing funding through an ANU PhD scholarship; the Australian Department of Education, Employment and Workplace Relations for an International Postgraduate Research Scholarship; the German National Academic Foundation and the Zeiss Foundation for support through a Heinz-Dürr Scholarship; and the Australian Institute of Marine Sciences for providing accommodation and facilities during fieldwork in Queensland.
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Harvey, Mark C. "Effects of social status and food availability on predator avoidance behaviour in young-of-the-year rainbow trout, oncorhynchus mykiss." Thesis, 2005. http://spectrum.library.concordia.ca/8563/1/MR10204.pdf.
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Prey animals are often faced with a Hobson's choice: risk starvation or risk predation. Individuals capable of optimizing this trade-off through the use of context specific predator avoidance behaviour should be at a selective advantage. Food availability and social status have been shown to exert a strong influence on this trade-off, however, it remains unknown if these factors interact (i.e., do dominants and subordinates vary their behavioural decisions based on food availability). The purpose of this study was to examine the effects of food availability and social status, as well as their interaction, on the individual behaviour by young-of-the-year rainbow trout (Oncorhynchus mykiss) in response to perceived predation threats. Pairs of dominants and subordinates were assigned to either low, intermediate or high food availability treatments and exposed to either conspecific alarm cue (predation threat) or distilled water (no threat). The results suggest that an individual's response to a perceived predation threat is indeed dependent upon both social status and food availability.
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Pfeil, Andreas. "Going underground : predator avoidance in Uca vomeris." Master's thesis, 2007. http://hdl.handle.net/1885/149660.
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Lee, Chien-Huei, and 李健暉. "Predator avoidance and mating behavior in calanoid copepod Pseudodiaptomus annandalei." Thesis, 2006. http://ndltd.ncl.edu.tw/handle/78092909685159813040.
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碩士國立臺灣海洋大學
海洋生物研究所
94
The fitness of an organism depends upon its efficiency to escape from predator and probability of procuring mate. Copepod’s ability of escape from predation and also its mating success are highly influenced by various hydromechanical signals in the aquatic environment. The purpose of this study is to investigate the efficiency of the copepod Pseudodiaptomus annandalei to escape from predation by the fish larvae Epinephelus coioides and it’s mating success in calm and turbulent water under dark and light conditions. These experiments were also designed to assess the impact of various strength of turbulence (weak, medium and high) and the strength as well as intensity of air bubbling (600, 1200 and 1800 ml per min) on the copepod’s vulnerability to fish predation. The detection of predator’s presence and subsequent escape ability of the copepod were significantly higher in calm water than that in the turbulent water. In calm water P. annandalei was able to dart away from the fish larvae at the speed about 103 body lengths per second. Regardless of external hydromechnical signal the removal of the copepod by the fish larvae was significant higher under light condition than that in the dark. Additionally the turbulence versus calm water related differences in the vulnerability of the Pseudodiaptomid copepod to fish predation was not significant under the dark condition. According to video observations, the Pseudodiatomus annandalei has a typical mating behavior. The mating processes are encounting, pursuiting, capturing and copulation. Based on the video recording and its behavior performance, P. annandalei seems to use chemical cue such as pheromone to locate its female mate. Male copepods exhibit typical searching behaviors e.g. either accelerate its swimming speed and/or turning its swimming path in order to locate the source of the chemical cue. According to video observations, the male copepods can find its mate and copulation even under weak turbulent environment.
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"SUB-LETHAL EFFECTS OF ROUNDUP ON TADPOLE DEVELOPMENT AND PREDATOR AVOIDANCE." Thesis, 2014. http://hdl.handle.net/10388/ETD-2014-01-1406.
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Roundup is a commonly used pesticide applied to agriculture and forest habitats. In Canada and parts of the North Eastern United States, these areas are generally optimal for amphibians due to the presence of small, ephemeral water bodies. While Roundup has been shown to have no adverse effects on a number of species, amphibians are one of the few groups who show high sensitivity to Roundup. My research aims to determine how an acute sub-lethal dose of Roundup affects several different facets of larvae development in wood frogs (Lithobates sylvaticus). In Chapter 2 I examined the effect of Roundup on amphibian development. Groups of tadpoles were treated with Roundup (0.5 mg a.e./L) for four days at three different times in their development (Gosner stage 26, 31-32 and 37-38), while a control group was maintained in similar conditions without Roundup. Pictures were taken every four days until tadpoles reached metamorphosis. Changes in development, body area or length were assessed, along with metamorphic endpoints, such as timing of metamorphosis and weight. Although there was no differential effect of Roundup on tadpole growth or weight, there was a slight, non-ecologically relevant, delay in development in tadpoles treated with Roundup at stage 26. The delay was not detectable in the second half of the experiment, indicating that compensatory mechanisms allowed those individuals to recover. Neither time to metamorphosis or weight at metamorphosis were affected by an environmentally relevant exposure to Roundup. In Chapter 3 I focused on the effect of Roundup on crucial behaviours related to the ability of larval amphibians to detect and avoid predation threats. I demonstrated that being exposed to Roundup for one hour eliminated the response of larval wood frogs to cues from injured conspecifics (i.e. cues known to elicit dramatic anti-predator responses in a wide variety of aquatic species). Tadpoles that were maintained in clean water and exposed to a combination of injured conspecific cues and Roundup, did not exhibit a decrease in movement, when compared to control tadpoles. This result indicates that Roundup deactivates the alarm function of the injured conspecific cues. However, it is possible that both the cues and the animal would be affected by Roundup. In Chapter 3 I also demonstrated that tadpoles that were exposed to Roundup as embryos had reduced basal movement rates. The results of this thesis illustrate that an environmentally relevant concentration of Roundup (0.5 mg a.e./L), does not negatively affect the development of tadpoles. The studies outlined in this thesis suggest that at this exposure concentration, behaviour acts as a more sensitive endpoint, than more traditional morphologic endpoints.
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Melaik, Gregory Louis. "Temperature related aggression and predator avoidance in the Eastern collared lizard (Crotaphytus collaris)." 1986. http://hdl.handle.net/2097/22114.
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Large, Scott Isaac. "Biogeographic Patterns, Predator Identity, and Chemical Signals Influence the Occurrence and Magnitude of Non-lethal Predator Effects." Thesis, 2011. http://hdl.handle.net/1969.1/ETD-TAMU-2011-08-10231.
Full textAbstract:
Predators can have large effects on prey populations and on the structure and function of communities. In addition to direct consumption of prey, predators often cause prey to alter their foraging behavior, habitat selection, and morphology. These non-lethal effects of predators can propagate to multiple trophic levels and often exert equal or larger effects upon communities than those of direct consumption. For non-lethal predatory effects to occur, prey must detect and respond to predation risk. While the importance of information transfer in this process has been realized, few studies explore how prey responses are influenced by predator characteristics and environmental conditions that influence the transmission of cues indicative of predation risk. In this dissertation I investigate factors that influence how a single prey species evaluates and responds to predation risk. Here, I examined: 1) the type and nature of cues prey use to evaluate predator risk; 2) how predator identity, predator diet, and the relative risk of predators influence prey response to predation risk; 3) how hydrodynamic conditions influence the delivery of predator cues; 4) how biogeographic trends in predator distribution influence prey response to predation risk; and 5) how genetic structure might vary according to prey geographic location and habitat. To address these questions, I used a common intertidal model system consisting of the rocky intertidal whelk Nucella lapillus (Linnaeus, 1758) and a suite of its predators, the native rock crab Cancer irroratus (Say, 1817), Jonah crab Cancer borealis (Stimpson, 1859), and the invasive
green crab Carcinus maenas (Linnaeus, 1758). Nucella use chemical cues emanating from their most common predator (Carcinus maenas) and crushed conspecifics to evaluate predation risk. Nucella from different habitats experience different levels of predation risk, and Nucella from habitats with high levels of predation had larger antipredatory responses to predator risk cues than Nucella that experienced less predation. These chemical cues indicative of predation risk are influenced by hydrodynamic conditions, and Nucella have the strongest anti-predatory response in flow velocities of u= ~4- 8 cm s^-1. Furthermore, Nucella from geographic regions where green crabs are historically absent did not elicit anti-predatory responses, while Nucella from regions where green crabs are common frequently responded. Findings from my dissertation research demonstrate that prey detection and response to predation risk is highly dependent upon predator identity, predator diet, environmental forces, and biogeographic patterns in predator and prey distributions.
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RUS, Tomáš. "Ovlivňuje přítomnost predátora aktivitu pulců? Srovnání reakce dvou druhů s odlišnou zkušeností s predátorem." Master's thesis, 2008. http://www.nusl.cz/ntk/nusl-47982.
Full textAbstract:
Responses of tadpoles Bombina variegata (likely unexperienced with predator) to pulses of risk and safety were tested and compared with results of a bachelor thesis previously done on tadpoles Bufo bufo (species likely experienced with predator) to confirm the risk allocation hypothesis. Differences of overall activity of both species were not significant. Differences in activity between Bufo bufo and Bombina variegata tadpoles held in continual risk conditions were observed. Such behavior possibilities are discussed.