Kairomones are infochemicals that benefit a heterospecific receiver. Chaoborus spp. release a kairomone from their gut when feeding on Daphnia spp. Daphnia respond to kairomone by shifting life history parameters or producing neonates with induced morphological defenses, increasing their chance of survival. When laboratory-cultured Daphnia are exposed to environmentally-relevant metal concentrations, a kairomone response is not induced, increasing predation vulnerability. Currently Daphnia live in metal-contaminated lakes in Sudbury, ON. It is possible the extant population is tolerant of relatively high copper (Cu) concentrations and can still induce a kairomone response. In comparison, it is hypothesized clones found in lakes isolated from anthropogenic sources of metal-contamination would be less tolerant as they have not been exposed to high Cu concentrations. The purpose of this study was to examine how multiple clones of D. pulicaria obtained from lakes along a Cu gradient respond to kairomone in the absence and presence of copper. Several different clones from Ontario lakes located in the Canadian Shield were exposed to environmentally-relevant Cu concentrations and Chaoborus kairomone. Neonates were collected and measured to assess predator-induced defenses. Results indicate that kairomone-mediated responses and Cu-tolerance vary among D. pulicaria clones. Clones from the Sudbury area were able to induce a response to kairomone when exposed to Cu, indicating a Cu-tolerance. However, this was not true for all Sudbury clones. In contrast, most clones from clean lakes did not respond to kairomone when exposed to Cu; while some clones exhibited a Cu-tolerance. Clones that were not tolerant of Cu were affected at concentrations much lower than those predicted by the Biotic Ligand Model (BLM) that induce acute toxicity. Predictions generated by the BLM can be conservative making them useful when creating water quality criteria; however, my results indicate these predictions can also be under-protective. Chemosensory cues mediate vital life processes that are essential for survival. Populations may be devastated if metals interfere with chemosensory cues. Overall, the results of my study suggest that genetic variation is important for population establishment and maintenance, specifically when exposed to multiple stressors, and that directional selection may result in stress tolerance. / Thesis (Master, Biology) -- Queen's University, 2009-12-23 09:50:46.152

Made available in DSpace on 2014-06-11T19:30:12Z (GMT). No. of bitstreams: 0 Previous issue date: 2010-01-29Bitstream added on 2014-06-13T19:39:29Z : No. of bitstreams: 1 morishita_vr_me_botib.pdf: 211575 bytes, checksum: a3ab5818527a4bb08b91f5efcd53a520 (MD5) / Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) / Ouriços-do-mar são capazes de avaliar o ambiente externo a partir de pistas químicas, por meio de quimiorreceptores presentes em seus espinhos, pés ambulacrários e pedicelárias. Neste estudo, utilizamos pistas químicas que indicam potencialmente o risco de predação de maneira diretas (odor de predador) ou indiretas (odor de coespecífico injuriado fisicamente) para avaliar os padrões de resposta de Echinometra lucunter. Num primeiro experimento, avaliamos a respostas dos ouriços expostos ao odor de estrela-do-mar equinívora Oreaster reticulatus em 1) jejum, alimentada com 2) E. lucunter, 3) Lytechinus variegatus ou 4) Perna perna; estrela-do-mar não equinívora Echinaster brasiliensis alimentada com 5) P. perna ou expostos a 6) água do mar sintética não condicionada (veículo). Num segundo experimento, os ouriços foram expostos ao extrato de 1) E. lucunter, 2) L. variegatus, 3) P. perna e 4) veículo. Esses estudos mostraram que E. lucunter é capaz de identificar, distinguir e reagir a diferentes extratos de animais, coespecíficos ou não. A dieta do predador modula a intensidade de resposta do E. lucunter, sendo mais pronunciadas as respostas frente ao odor de estrela que se alimentou de presas coespecíficas. Para o extrato, identificamos as respostas aos extratos de equinóides, sendo a mais forte para os de E. lucunter. Visto que muitos vertebrados respondem a estímulos similares qualitativamente, especulamos que esse comportamento anti-predatório possa ter evoluído a partir dos Echinodermata, grupo basal dos deuterostômios / Sea urchins are able to evaluate chemical information from the environment by using chemosensory receptors in their spines, tube feet and pedicellariae. In this study, we used chemical cues that potentially indicate directly (predator odor) or indirectly (injured conspecific) predation risk to assess antipredator behavior in the black sea urchin Echinometra lucunter. In a first experiment, the urchins were exposed to echinivorous starfish Oreaster reticulatus 1) starved, fed on 2) E. lucunter, 3) Lyfechinus variegatus or 4) Perna perna; nonechinivorous starfish 5) Echinaster brasiliensis fed on P. perna or exposed to 6) the vehicle, synthetic salt-water (control). In a second experiment, the urchins were exposed to extract of crushed 1) E. lucunter, 2) L. variegatus, 3) P. perna and 4) the vehicle (control). This study shows that E. lucunter are able to identity, distinguish and react to different animais extracts, conspecifics or not. Predator diet modulates E. lucunter intensity of behavioral responses. The response to echinivorous starfish odor fed on conspecifics is more pronounced. For the extract, urchins responded only to echinoids ones, and the response to extract of E. lucunter was the strongest. Speculatively, since vertebrates respond to qualitative similar stimuli, this kind of antipredator behavior might have evolved from the Echinodermata, a basal group of deuterostomes

Velvet ants are a group of parasitic wasps that are well known for a suite of defensive adaptations including bright coloration and a formidable sting. While these adaptations are presumed to function in antipredator defense, observations between potential predators and this group are lacking. We conducted a series of experiments to determine the risk of velvet ants to a host of potential predators including amphibians, reptiles, birds, and small mammals. Velvet ants from across the United States were tested with predator's representative of the velvet ants native range. All interactions between lizards, free-ranging birds, and a mole resulted in the velvet ants survival, and ultimate avoidance by the predator. Two shrews did injure a velvet ant, but this occurred only after multiple failed attacks. The only predator to successfully consume a velvet ant was a single American toad (Anaxyrus americanus). These results indicate that the suite of defenses possessed by velvet ants, including aposematic coloration, stridulations, a chemical alarm signal, a hard exoskeleton, and powerful sting are effective defenses against potential predators. Female velvet ants appear to be nearly impervious to predation by many species whose diet is heavily derived of invertebrate prey.

I examined the effect of the conspecific mobbing call of the Red-backed Shrike (Lanius collurio) on nest defence against arial predator (kestrel). I used a playback experiment in the presence of a dummy of kestrel (Falco tinnunculus) in two variants either with nature look or with adjusted key features (pigeon beak, claws and eyes), and pigeon (Columba palumbus) as a control. Shrikes were attracted by the mobbing call and arrived to their nests faster. Only the modified kestrel was attacked more likely in the presence of the playback, that suggests possible function of the mobbing call as a cue for social learning of predator recognition.

Orientador: Rodrigo Egydio Barreto / Banca: Gilson Luiz Volpato / Banca: Ronaldo Adriano Christofoletti / Resumo: Ouriços-do-mar são capazes de avaliar o ambiente externo a partir de pistas químicas, por meio de quimiorreceptores presentes em seus espinhos, pés ambulacrários e pedicelárias. Neste estudo, utilizamos pistas químicas que indicam potencialmente o risco de predação de maneira diretas (odor de predador) ou indiretas (odor de coespecífico injuriado fisicamente) para avaliar os padrões de resposta de Echinometra lucunter. Num primeiro experimento, avaliamos a respostas dos ouriços expostos ao odor de estrela-do-mar equinívora Oreaster reticulatus em 1) jejum, alimentada com 2) E. lucunter, 3) Lytechinus variegatus ou 4) Perna perna; estrela-do-mar não equinívora Echinaster brasiliensis alimentada com 5) P. perna ou expostos a 6) água do mar sintética não condicionada (veículo). Num segundo experimento, os ouriços foram expostos ao extrato de 1) E. lucunter, 2) L. variegatus, 3) P. perna e 4) veículo. Esses estudos mostraram que E. lucunter é capaz de identificar, distinguir e reagir a diferentes extratos de animais, coespecíficos ou não. A dieta do predador modula a intensidade de resposta do E. lucunter, sendo mais pronunciadas as respostas frente ao odor de estrela que se alimentou de presas coespecíficas. Para o extrato, identificamos as respostas aos extratos de equinóides, sendo a mais forte para os de E. lucunter. Visto que muitos vertebrados respondem a estímulos similares qualitativamente, especulamos que esse comportamento anti-predatório possa ter evoluído a partir dos Echinodermata, grupo basal dos deuterostômios / Abstract: Sea urchins are able to evaluate chemical information from the environment by using chemosensory receptors in their spines, tube feet and pedicellariae. In this study, we used chemical cues that potentially indicate directly (predator odor) or indirectly (injured conspecific) predation risk to assess antipredator behavior in the black sea urchin Echinometra lucunter. In a first experiment, the urchins were exposed to echinivorous starfish Oreaster reticulatus 1) starved, fed on 2) E. lucunter, 3) Lyfechinus variegatus or 4) Perna perna; nonechinivorous starfish 5) Echinaster brasiliensis fed on P. perna or exposed to 6) the vehicle, synthetic salt-water (control). In a second experiment, the urchins were exposed to extract of crushed 1) E. lucunter, 2) L. variegatus, 3) P. perna and 4) the vehicle (control). This study shows that E. lucunter are able to identity, distinguish and react to different animais extracts, conspecifics or not. Predator diet modulates E. lucunter intensity of behavioral responses. The response to echinivorous starfish odor fed on conspecifics is more pronounced. For the extract, urchins responded only to echinoids ones, and the response to extract of E. lucunter was the strongest. Speculatively, since vertebrates respond to qualitative similar stimuli, this kind of antipredator behavior might have evolved from the Echinodermata, a basal group of deuterostomes / Mestre

Many organisms utilize toxic or noxious compounds as a means of deterring predation. Eastern newts (Notopthalmus viridescens), along with other species in the family Salamandridae, possess a potent neurotoxin called tetrodotoxin (TTX). Although TTX can serve as an effective antipredator mechanism in species of newts with high concentrations (e.g., Taricha), eastern newts have relatively low levels of toxicity in comparison to those species, and it may not serve as an effective antipredator mechanism against all threats. In this case, they may benefit rather by utilizing behavioral changes to avoid initial contact with predators. We tested for predator-avoidance behavior in newts by exposing individuals to kairomones from various predators. We recorded activity patterns of newts when they were exposed to cues from potential predators including bullfrogs (Lithobates catesbeiana), water snakes (Nerodia sipedon) and snapping turtles (Chelydra serpentina), as well as a non-predator (bullfrog tadpoles), and a control (deionized water). Newts reduced activity when exposed to snapping turtle stimuli, but did not change activity when exposed to any other chemical cues. We verified that newts interact with this predator by trapping snapping turtles found in ponds from which newts were collected. Finally, we used turtles caught during this sampling to test whether they are an actual predator of newts and whether newts shift microhabitat use when exposed to this predator. In each replicate, turtles consumed newts, and newts spatially avoided the snapping turtle, relative to a control. The results of these experiments indicate newts rely on predator-avoidance behavior to reduce the probability of being consumed by snapping turtles, but do not reduce activity in response to other potential predators that may only consume them rarely.

京都大学 / 0048 / 新制・課程博士 / 博士(理学) / 甲第18104号 / 理博第3982号 / 新制||理||1574(附属図書館) / 30962 / 京都大学大学院理学研究科生物科学専攻 / (主査)准教授 森 哲, 教授 沼田 英治, 教授 疋田 努 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

京都大学 / 新制・課程博士 / 博士(理学) / 甲第24453号 / 理博第4952号 / 新制||理||1707(附属図書館) / 京都大学大学院理学研究科生物科学専攻 / (主査)教授 森 哲, 教授 中務 真人, 教授 中川 尚史 / 学位規則第4条第1項該当 / Doctor of Science / Kyoto University / DGAM

No description available.

We have examined wild palearctic and nearctic parids in their ability to recognize and assess a threat level of sympatric and allopatric predators. The study was conducted in Prague, Czech republic, on great tits (Parus major) and blue tits (Parus caeruleus) during the winter of 2013, and the following year in the city of Calgary, Canada, on black-capped chickadees (Poecile atricapillus). Three species of falcons (merlin (Falco columbarius), common kestrel (Falco tinnunculus) and american kestrel (Falco sparverius)), were chosen, two of which were sympatric and one was allopatric to the studied parid species in each area. We have also tested their reaction to nest predators magpies (eurasian magpie (Pica pica), black-billed magpie (Pica hudsonia)). Using two ground feeders in the winter time, we gave parids a choice between a feeder with either one of the three dummies of falcons, or a magpie, and a feeder with a dummy of either a hawk (the most dangerous predator of small birds) or a dove (a harmless bird of the same size as falcons). As a control we have only used sympatric species: eurasian sparrowhawk (Accipiter nisus), Cooper's hawk (Acipiter cooperii), eurasian collared dove (Streptopelia decaocto) and mourning dove (Zenaida macroura). Results from the city of Calgary did not produce any...