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Guilford, T. "Aposematism." Thesis, University of Oxford, 1987. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.382678.
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Teichmann, J. "Models of aposematism and the role of aversive learning." Thesis, City University London, 2015. http://openaccess.city.ac.uk/13431/.
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The majority of species are under predatory risk in their natural habitat and targeted by predators as part of the food web. Through the process of evolution by natural selection manifold mechanisms have emerged to avoid predation. As Fisher argued, it is the ubiquitous presence of anti-predator adaptations which shows that predation plays a significant role in the ecology and evolution of ecosystems. These ecosystems are intrinsically complex which derives from the high entanglement of organisms interacting in competitive relationships: the prey is part of the predator’s environment and vice versa. As a result, the evolution of predator and prey is best described as a co-evolutionary process of predator-prey systems. It is common to classify anti-predator adaptations into ‘primary defences’ and ‘secondary defences’. Primary defences operate before an attack by reducing the frequency of detection or encounter with predators. Secondary defences, which are used after a predator has initiated prey-catching behaviour, commonly involve the expression of toxins or deterrent substances which are not observable by the predator. Hence, the possession of such secondary defence in many prey species comes with a specific signal of that defence. This pairing of a toxic secondary defence and a conspicuous primary defence is known as aposematism. Previous models mainly focused on questions of the initial evolution of aposematism in ancestrally cryptic populations. However, the field has a renewed interest in questions beyond the initial evolution of aposematism such as: how conspicuous should a signal be, and how much should be invested into secondary defence? Moreover, which factors influence evolutionary stability of aposematic solutions. Within this context, the role of co-evolution and the mechanisms of aversive learning are at the heart of the current research. On the one hand, to explain stability and persistence of aposematic signals requires a theory of co-evolution of defence and signals. On the other hand, the role of the predator and details of the predator’s aversive learning process gained renewed interest of the field. As the selective agent, aversive learning is an important aspect of predator avoidance and of the co-evolution of predator-prey systems. In the first chapter, this thesis will review the literature on aposematism and introduce the different selective pressures acting on aposematic prey. The thesis will then identify open questions of interest around aposematism. In the second chapter the thesis will focus on the perspective of the prey. The introduction of a game theoretical model of co-evolution of defence and signal will be followed by an adaptation of the model for finite populations. In finite populations, investigating the co-evolution of defence and signalling requires an understanding of natural selection as well as an assessment of the effects of drift as an additional force acting on stability. In the third chapter the thesis will adopt the perspective of the predator. It will introduce reinforcement learning as an normative framework of rational decision making in a changing environment. An analysis of the consequences of aposematism in combination with aversive learning on the predator’s diet and energy intake will be followed by a lifetime model of optimal foraging behaviour in the presence of aposematic prey in the fourth chapter. In the last chapter I will conclude that the predator’s aversive learning process plays a crucial role in the form and stability of aposematism. The introduction of temporal difference learning allows for a better understanding of the specific details of the predator’s role in aposematism and presents a way to take the discipline forward.
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Rudh, Andreas. "Aposematism, Crypsis and Population Differentiation in the Strawberry Poison Frog." Doctoral thesis, Uppsala universitet, Zooekologi, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:uu:diva-175240.
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Evolutionary transitions between the two major predator avoidance strategies aposematism and crypsis are expected to be associated with changes in many important traits of animals. However, empirical studies on populations experiencing ongoing or recent transitions between these strategies are rare. This thesis investigates the co-evolution of traits among populations of the Strawberry poison frog D.pumilio in Bocas del Toro, Panama. I found that all investigated populations were genetically distinct but that colour and pattern did not correlate with genetic or geographic distance, which suggests that selection needs to be invoked to explain the observed variation. Based on the chromatic contrast between frog dorsal colour and the natural habitat substrates used by the frogs, the populations were defined as bright or dull coloured. I found that frogs from bright coloured populations were larger. This is expected if aposematism is enhanced by large signals while crypsis is enhanced by small size. Further, individuals from bright coloured populations had a coarser black dorsal pattern, which is expected if crypsis is impaired by a bold pattern. The importance of pattern coarseness was confirmed by an avian detection experiment showing that coarse patterned dark green prey were more easily detected than dark green prey without pattern or with fine pattern. I put forward the hypothesis that enhanced protection, gained by aposematism, may affect behaviours that influence dispersal and pairing patterns. Indeed, males from bright coloured populations displayed at more exposed sites and showed a tendency to be more explorative and aggressive. In summary, my results show that the bright and dull coloured populations most likely represent an aposematic and a cryptic strategy, respectively. Furthermore, I show that evolutionary changes between aposematism and crypsis can be associated with coevolution of both morphology and behaviour. I argue that this coevolution may increase the likelihood of both pre- and post-zygotic reproductive isolation. This is because greater phenotypic differences between populations increase the likelihood of selection against badly adapted migrants and hybrids with intermediate traits.
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Oliveira, Filho Jaires Gomes de. "Uso de compostos repelentes produzidos por cães resistentes ao Rhipicephalus sanguineus sensu lato para o seu controle em cães susceptiveis." Universidade Federal de Goiás, 2018. http://repositorio.bc.ufg.br/tede/handle/tede/8188.
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Rhipicephalus sanguineus sensu lato, the "brown dog tick", preferentially parasite the domestic dog, in the latter can parasite others mammals species including humans. This tick demonstrates a hunting behavior by its host, being widely attracted by the bark and the CO2 among other signs related to the presence of its hosts. Despite being commonly found parasite on dogs, it is known that some breeds such as beagles are less parasitic than other breeds like English Cocker Spaniel which can present a parasitic load about up to 11.5 times higher than mongrel dogs. It is notable a capacity of ticks and other arthropods in their hosts in relation to desirable or undesirable characteristics that can perceive these by means of chemoreception of volatile compounds emanated by these hosts. This adaptive tool is called olfactory aposematism. Olfactory apostotism is capable of an ectoparasite in avoiding its hosts through a perception of a volatile chemical emanated by it that signals a negative adaptive response to the arthropod. Usually this response may be linked to immune factors, excessive grooming, inaccessibility or other factors. One of the big problems nowadays undoubtedly is the control of ticks and diseases that are transmitted to their hosts during the blood repast. One of the alternatives for control of parasitism in order to deter ticks from the search for their hosts is a use of compounds found in resistant hosts that are interpreted by these arthropods as non-hosts. These compounds demonstrate a more specific activity between arthropod parasites and their hosts, since they were selected during an adaptation between species involved in this parasite-host relationship forging bases of parasite selection by susceptible and resistant hosts.
Rhipicephalus sanguineus sensu lato, também conhecido como “carrapato marrom do cão”, parasita preferencialmente o cão doméstico, no entanto pode parasitar inúmeras outras espécies mamíferas inclusive seres humanos. Este carrapato demonstra um comportamento de busca ativa por seu hospedeiro, sendo amplamente atraído pelo latido e pelo CO2 e outros sinais relacionados a presença de seus hospedeiros. Apesar de parasitar preferencialmente cães sabe-se que algumas raças como o beagle são menos parasitadas que outras raças como Cocker spaniel inglês que podem apresentar uma carga parasitaria cerca de até 11,5 vezes maior que cães mestiços. É notável a capacidade de carrapatos e demais artrópodes tem em selecionar seus hospedeiros em relação a características desejáveis ou indesejáveis que conseguem perceber destes, por meio da quimiorrecepção de compostos voláteis emanados pelos hospedeiros. A esta ferramenta adaptativa damos o nome aposematismo olfativo que é capacidade de um de parasito em evitar seus hospedeiros mediante a percepção de um químico emanado por este que sinalize uma resposta adaptava negativa ao artrópode. Geralmente esta resposta pode estar ligada a fatores imunes, excesso de grooming ou inacessibilidade ou demais fatores. Um dos grandes problemas na atualidade sem dúvida e o controle de carrapatos e doenças que são transmitem a seus hospedeiros durante o repasto sanguíneo. Uma das alternativas para o controle de parasitismo afim de dissuadir os carrapatos da busca por seus hospedeiros é uma utilização de compostos encontrados em hospedeiros resistentes que são interpretados por estes artrópodes como não hospedeiros. Estes compostos demonstram atividade mais especifica entre artrópode parasitos e seus hospedeiros, pois foram selecionados durante uma adaptação entre espécies envolvidas nesta relação parasitohospedeiro forjando bases da seleção de parasitos por hospedeiros suscetíveis e resistentes.
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Kazemi, Baharan. "Evolution of Mimicry and Aposematism Explained: Salient Traits and Predator Psychology." Doctoral thesis, Stockholms universitet, Zoologiska institutionen, 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-148488.
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Aposematic species have evolved conspicuous warning signals, such as bright colors and striking patterns, to deter predators. Some edible and harmless species take advantage of this deterrent effect by mimicking their appearance. Mimicry is a great example of how natural selection produces remarkable adaptations. However, while some species evolve a very close similarity to their models to effectively avoid attacks, others are successful in doing so despite an incomplete similarity, i.e. imperfect mimicry. In some cases, it is surprising how such a crude disguise can fool predators. Why and how imperfect mimicry can persist has been much discussed and considered as a problem for the theory of natural selection. It is therefore of great interest to understand what makes it possible. Predator psychology is an important factor in the evolution of aposematism and mimicry. In the past decades it has been suggested that certain components of prey appearance are more important to predators than others during prey assessment. We developed this idea by incorporating concepts from associative learning, and presented a new approach to explain imperfect mimicry. Our general hypothesis is that prey traits have different salience to predators. Certain traits are perceived as highly salient and are thus used primarily in the discrimination and generalization of prey, while traits with low salience are overshadowed and not used in the assessment. The salience of a trait can depend on how conspicuous or discriminable it is in the particular context, and can vary due to for example previous predator experience. We tested our ideas with wild blue tits and domestic chickens as predators, and artificial and semi-natural prey stimuli. In paper I we found that the trait that was perceived as most salient (color) was the one used to discriminate and generalize between prey. Mimics of that specific trait were highly avoided, despite differences in the other traits. We also found that salience is relative and context dependent (paper II). In a context where two traits were perceived as similarly salient, mimicry of a single trait offered intermediate protection, while mimicry of both offered high protection. In another context, the traits were perceived differently salient, and mimicry of one trait was enough for high protection. In paper III we tested a proposed scenario for the initiation of mimicry evolution in the edible butterfly mimic Papilio polyxenes asterius to its noxious model Battus philenor. The results showed that a partial similarity with the model in the salient black wing color offered intermediate protection from attacks, despite a general dissimilarity. This thesis investigates the major questions of imperfect mimicry: the initial step of mimicry evolution, the persistence of imperfect mimicry, and variation in mimic-model similarity. We conclude that mimicry evolution can begin in a non-mimetic species that acquires similarity to a model species in a high-salience trait. When multiple traits have similar salience, multi-trait mimicry is needed for higher protection. Mimicry can remain imperfect if the differences are in traits with low salience, and therefore under low or no selection pressure to change. To complete the picture, we showed that predators can have a biased generalization toward a more pronounced version of a salient trait (paper IV). The evolution of aposematism could therefore be explained by gradual enhancement of salient traits.At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Accepted. Paper 4: Manuscript.
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Mann, Victoria. "The Characteristics of Aposematism and Noxious Spray in the Striped Skunk (Mephitis mephitis)." Thesis, California State University, Long Beach, 2018. http://pqdtopen.proquest.com/#viewpdf?dispub=10752121.
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Skunk spray produced in the anal glands of the striped skunk can have extremely adverse effects on potential predators, who then learn to avoid provoking these animals in the future. Despite this spray being an extremely effective predator deterrent, few studies have assessed the molecular constituents found within striped skunk spray, and no studies have attempted to assess how important ecological factors could influence the strength of the spray. The goal of this study was to assess the honesty of striped skunk pelage and the influence of predation risk and life history on skunk musk by measuring the variation in the amounts of the major noxious chemicals of skunk spray, using gas chromatography-mass spectrometry (GC-MS). A total of fifty-eight anal secretion samples and dorsal stripe images were collected from striped skunks from two separate locations differing in mammalian and avian predation risk. Overall, the findings of this study support the hypothesis that striped skunk spray and pelage whiteness varies more in areas with greater risk of predation by mammals, and anal secretion noxiousness is influenced by the skunk’s weight, sex, and reproductive state. The aposematic coloration exhibited by skunks as well as the defensive spray mechanism is largely influenced and selectively maintained by mammalian predation pressures.
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Flores, De Gracia Eric Enrique. "Early development and the honesty of aposematic signals in a poison frog." Thesis, University of Exeter, 2012. http://hdl.handle.net/10871/8170.
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The causes and consequences of variation in aposematic signals during immature stages are not clearly understood. This thesis explores the effects of early environment on the expression of aposematic signals in the green and black poison frog (Dendrobates auratus), and the consequences of variation in such components in the wild. It also explores how aposematic expression relates to levels of chemical defences in immature froglets. Embryos and larvae of poison frogs in the genus Dendrobates are known to be darkly pigmented. This thesis reports for the first time polymorphism in egg pigmentation in D. auratus and ontogenetic colour change through development reverting to a normally pigmented phenotype; however whether this pigmentation results from constraints or has adaptive consequences remains unclear. Evidence on how immature individuals allocate resources to growth and warning signalling is scarce. Experimental results in this thesis show that food supply during early environment affected body size and signal luminance in post-metamorphic froglets. Therefore the relative importance of these traits in relation to predation risk was further tested, using artificial prey in a field experiment. The results indicated that rates of attack by birds correlated negatively with body size, and on the contrary survival of artificial prey was independent of signal luminance. I therefore tested the hypothesis that in the wild larger, relatively well-nourished juvenile frogs are chemically better defended. I found that in fact larger juveniles are at a selective advantage conferred by their greater foraging efficiency and their superior levels of chemical defences. Overall, these results shows plasticity in aposematic traits in relation to early environmental nutrition in D. auratus; and suggests that acquiring large body size and similar integument colour as to adults are key determinants for survival during the early stages of their terrestrial life.
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Paul, Sarah Catherine. "The price of defence : maternal effects in an aposematic ladybird." Thesis, University of Exeter, 2016. http://hdl.handle.net/10871/25374.
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Offspring phenotype can be adaptively altered via maternal non-genetic inheritance. Such ‘maternal effects’ enable females to adjust their per offspring investment in response to variation in the offspring environment, and thus maximise their reproductive success. Consequently they play a pivotal role in population dynamics and the response of species to environmental change. Despite this, little is known about how maternal effects mediate reproductive investment in response to multiple or novel environmental changes, such as those driven by anthropogenic activity. I use the 2-spot ladybird intraguild predation system, where resources and predation risk are highly variable, to explore the role of maternal effects in the response of a native species to an invasive predator, as well as answering outstanding questions about how maternal effects function under complex and antagonistic sets of variables. The results indicate that it is unlikely that maternally mediated changes in egg phenotype will improve the survival of 2-spot ladybird offspring in the face of predation from larvae of the invasive harlequin ladybird. They do, however, demonstrate the importance of studying maternal effects in the context of the multiple environmental factors, which more accurately represent the complex environments in which organisms live and evolve, corroborating recent theoretical predictions. Finally I provide evidence of the multifaceted nature of parental effects in aposematic species and reveal the role that they may play in shaping the variation in defence and warning coloration observed in adult populations.
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Gonçalves, Nathalia Ximenes. "O papel da interação com presas e predadores na variação cromática de Gasteracantha cancriformis (Araneidae)." Universidade Federal de Goiás, 2017. http://repositorio.bc.ufg.br/tede/handle/tede/7756.
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The sensory drive theory predicts that signals, sensory systems, and signaling behavior should coevolve. Variation in the sensory systems of prey and predators may explain the diversity of color signals, such as color polymorphism. The spider Gasteracantha cancriformis (Araneidae) possesses several conspicuous color morphs. The aim of the present study was to assess whether the color polymorphism of G. cancriformis may be maintained by pressure from multiple signal receivers, such as prey and predators with distinct color vision systems. In orb-web spiders, the prey attraction hypothesis states that conspicuous colors are prey lures that increase spider foraging success via flower mimicry. However, in highly defended species, conspicuous colors could also be a warning signal to predators. We used color vision modelling to estimate chromatic and achromatic contrast of G. cancriformis morphs as perceived by potential prey and predator taxa. To assess the role of prey, we conducted a prey capture experiment in the field, in which webs were assigned to four treatments: yellow, red, and black models, or no model. For each treatment, we counted the number of prey trapped on the webs and the calculated webs damaged area. To assess the role of predators on the evolution of conspicuous color patterns and polymorphism, we conducted a second field experiment, allocating yellow, red and black spider models in nylon threads along the vegetation, and observed the number of attack markings for each of them. Our results revealed that individual prey and predator taxa perceive the conspicuousness of morphs differently. Therefore, the multiple prey and multiple predator hypotheses may explain the evolution of color polymorphism in G. cancriformis. The results of prey capture experiment did not corroborate the prey attraction hypothesis nor the prey specific adaptation of color polymorphism. On the predation experiment, we found that black spider models presented more markings, which indicates that yellow and red models were less preferred, possibly suggesting that spider coloration may play a role on predator avoidance. Our results, however, do not corroborate the hypothesis that multiple predators influence polymorphism evolution. Color polymorphism in this species is possibly a multi-functional attribute, where some morphs benefits from aposematism, whereas others may alternative fitness advantages. Non-adaptive explanation should also be considered in future experiments of the evolution and maintenance of color polymorphisms.
A teoria de “sensory drive” prediz que sinais, sistemas sensoriais e comportamentos de sinalização devem coevoluir. Variação no sistema sensorial de presas ou predadores pode explicar a diversidade de colorações existentes e polimorfismos de cores. A aranha de teia orbicular Gasteracantha cancriformis apresenta padrões de coloração conspícuos e polimorfismo de cor. A evolução e manutenção de tal variação cromática pode ser influenciada por presas e predadorescom sistemas visuais diferentes, já que um mesmo morfo é percebido distintamente por potenciais presas e predadores. A coloração conspícua, entretanto, não se assemelha à coloração de flores. Tampouco influencia na captura de presas, visto que modelos dessa aranhas apresentaram números similares de presas nas teias. Portanto, ao contrário de outras aranhas de teia orbicular, para as quais a coloração chamativa é atribuída ao mimetismo floral, para G. cancriformis, esta hipótese não é corroborada. Os morfos amarelo e vermelho apresentam coloração típica de organismos aposemáticos e são conspícuos para a visão de uma ave. O morfo vermelho apesar de não ser conspícuo na visão de vespas, ainda assim poderia estar protegido de predação por camuflagem. Dessa forma, esses morfos poderiam ser mantidos na população devido à pressão de diferentes predadores, morfos vermelhos sinalizariam impalatabilidade para aves, enquanto morfos amarelos, para vespas. Porém, essas diferenças não foram observadas experimentalmente. Em campo, modelos pretos de aranha apresentaram mais marcas de predação do que modelos amarelos e vermelhos, também sugerindo que em G. cancriformis a coloração chamativa pode ser um sinal de advertência para predadores. Porém, a multiplicidade de predadores por si só não explica a variação cromática em populações dessa espécie de aranha. Consequentemente, o polimorfismo de cor em G. cancriformis pode ser uma característica multi-funcional, onde morfos não aposemáticos seriam mantidos nas populações devido a outras funções adaptativas, como camuflagem ou termorregulação.
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Briolat, Emmanuelle Sophie. "The form and function of warning signals in Lepidoptera, with a special focus on burnet moths (Zygaenidae)." Thesis, University of Exeter, 2017. http://hdl.handle.net/10871/31659.
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Many species use visual features to avoid predation by several methods, such as concealing themselves, deceiving predators and hindering capture. One of the most striking strategies is aposematism, or warning coloration, in which prey use conspicuous visual signals to advertise chemical or physical defences, and thereby deter predators from attacking. My thesis focuses on the form of these warning signals, namely which elements of visual patterns might be most effective in generating predator avoidance, as well as how these different visual features relate to defence levels and ultimately to prey survival in the wild. To address these issues, I studied the warning signals of Lepidoptera and in particular burnet moths (Zygaenidae: Zygaeninae), day-flying moths with distinctive red and black wings and the remarkable ability to both synthesise defensive compounds and sequester them from their host plants. Technological advances and a growing understanding of animal vision mean that animal signals can be studied in an increasingly precise and ecologically-relevant way. Throughout this thesis, I use sophisticated methods to quantify both the defensive chemicals and wing coloration of burnet moths, as perceived by their avian predators. I examine the key features of day-flying defended Lepidoptera, then focus on the potential for quantitative signal honesty in burnet moths. I explore the relationship between defence levels and measures of coloration, both within the six-spot burnet moth, Zygaena filipendulae, and across species in the Zygaenidae, then test the effects of variation in warning signals on predation risk for artificial burnet-like prey in the field. My work highlights some of the complicating factors that should be accounted for in the study of warning coloration, especially when investigating the potential for quantitative signal honesty. I hope my thesis will provide a basis for future research on the defensive strategies of day-flying moths and inspire others to pursue investigations into aposematism in the Zygaenidae.
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Jovanovic, Olga [Verfasser], and M. [Akademischer Betreuer] Vences. "Natural history of Malagasy poison frogs: experimental analysis of aposematism, morphology of tadpoles, and longevity / Olga Jovanovic ; Betreuer: M. Vences." Braunschweig : Technische Universität Braunschweig, 2009. http://d-nb.info/1175829765/34.
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Prates, Ivan [UNIFESP]. "Mimetismo em anfíbios: Colorido, morfologia cutânea e veneno em Ameerega picta, Leptodactylus lineatus e Leptodactylus andreae." Universidade Federal de São Paulo (UNIFESP), 2010. http://repositorio.unifesp.br/handle/11600/9817.
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Previous issue date: 2010-08-25A pele dos anfíbios atua em muitas funções vitais, relacionadas à atividade de dois tipos de glândulas cutâneas: mucosas e granulosas. As glândulas granulosas (de veneno) atuam na defesa química que caracteriza os anfíbios, secretando uma grande diversidade de compostos. A presença de secreções de alta toxicidade está frequentemente associada a padrões de colorido chamativos, ditos apossemáticos, reconhecidos e evitado por predadores. O colorido de espécies apossemáticas pode estar presente também em certas espécies indefesas, que assim adquirem proteção, um fenômeno designado mimetismo batesiano. Por outro lado, um conjunto de espécies tóxicas pode apresentar colorido semelhante, caracterizando o chamado mimetismo mulleriano. Dentre os anfíbios, muitos casos de mimetismo envolvem rãs tóxicas e apossemáticas da família Dendrobatidae. A rã Leptodactylus lineatus (família Leptodactylidae) possui colorido similar ao de vários dendrobatídeos, em especial ao de Ameerega picta. Embora assumido como um mímico de A. picta, dentre outros dendrobatídeos, não há de fato evidências de que L. lineatus não secrete toxinas. Uma terceira espécie, Leptodactylus andreae, guarda semelhanças com essas duas no padrão de colorido. Essa investigação tencionou esclarecer a síndrome mimética envolvendo essas três espécies. Objetivou-se determinar: há mimetismo entre elas? Se sim, ele é de natureza batesiana ou mulleriana? Para tanto, atentou-se para a morfologia cutânea, com foco na estrutura e distribuição das glândulas de veneno, assim como para a bioquímica das secreções, o colorido da pele e informações de sua história natural. Foi observado que L. lineatus possui grande número de glândulas granulosas, que se apresentam concentradas em regiões de acúmulo na face dorsal e ventral do corpo. No dorso, esses acúmulos apresentam notável correlação com a posição de listas e manchas, sugerindo que o colorido sinaliza regiões onde o veneno está concentrado. Essas regiões são enfatizadas por um conjunto de posturas defensivas, que podem aumentar as chances de contato do predador com as toxinas ou favorecer o reconhecimento de L. lineatus. A distribuição glandular de L. andreae é semelhante, mas os acúmulos são mal definidos e possuem muito baixa densidade. A. picta, por outro lado, possui distribuição de glândulas uniforme no dorso e ventre. A caracterização histoquímica, bioquímica e ultraestrutural sugerem grande quantidade e diversidade de proteínas nas secreções de L. lineatus, dotadas de significativa atividade enzimática proteolítica. Por outro lado, as proteínas estão praticamente ausentes das secreções de A. picta, nas quais foram detectadas mucossubstâncias de caráter glicídico, que podem contribuir para a toxicidade da espécie. Os dados sugerem que, assim como A. picta, L. lineatus é uma espécie tóxica, que parece atuar como um co-mímico mulleriano desse e possivelmente de outros dendrobatídeos. Em contraste, a morfologia cutânea sugere que L. andreae apresenta baixa toxicidade, possivelmente atuando como um mímico batesiano de A. picta e L. lineatus. São apresentados dados sobre outros atributos da pele, como as glândulas mucosas e a presença de uma camada calcificada na derme. Os resultados são discutidos no contexto de diferenças entre as espécies com relação ao comportamento e ecologia.
TEDE
BV UNIFESP: Teses e dissertações
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Massuda, Kamila Ferreira 1979. "Mecanismos de defesa contra predadores em larvas da borboleta Methona themisto (Nymphalidae: Ithomiinae)." [s.n.], 2008. http://repositorio.unicamp.br/jspui/handle/REPOSIP/316371.
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Orientador: Jose Roberto TrigoDissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia
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Resumo: As defesas químicas em lepidópteros compreendem mecanismos que vão desde o seqüestro de compostos do metabolismo secundário de plantas até a biossíntese de novo de compostos que podem torná-los tóxicos ou impalatáveis. As larvas da borboleta Methona themisto (Nymphalidae: Ithomiinae), que apresentam coloração conspícua e se alimentam apenas da solanácea Brunfelsia uniflora, rica em compostos do metabolismo secundário, foram analisadas sob vários aspectos, para verificar se são quimicamente defendidas. O acompanhamento da sobrevivência das larvas indicou que a predação afeta significativamente a sobrevivência em seu ambiente natural. As defesas químicas dessas larvas são aparentemente ineficazes contra predadores invertebrados, como a aranha Lycosa erythrognatha e a formiga Camponotus crassus (100% dos indivíduos testados predaram as larvas), mas parecem ser eficazes contra os mantídeos Oxyopsis saussuurei (redução no tempo de manipulação da presa e predação em um segundo contato). Para predadores vertebrados como o lagarto Tropidurus itambere e a ave Gallus gallus, a defesa parece atuar em relação à palatabilidade e à coloração conspícua. Gallus gallus apresentou maior predação de larvas de 1o ínstar, sugerindo que há um incremento na impalatabilidade da larva no decorrer de seu desenvolvimento. Os testes de aprendizagem dos pintinhos demonstraram que com poucos contatos com a presa impalatável já se obtém uma resposta de rejeição visual. O emprego de uma larva de coloração semelhante a da Methona themisto indica que os pintinhos são capazes de relacionar a cor com o gosto desagradável, rejeitando assim uma presa palatável. Apenas extratos diclorometânicos das larvas testados com Gallus gallus foram significativamente rejeitados em relação a seus controles. Dessa forma, esses dados comprovam que as defesas químicas das larvas de Methona themisto atuam principalmente contra predadores vertebrados visualmente orientados
Abstract: Chemical defense in Lepidoptera involves several mechanisms such as sequestration of secondary metabolismcompounds of host plants and de novo synthesis of compounds that can provide some unpalatability or toxicity. The larvae of the butterfly Methona themisto (Nymphalidae: Ithomiinae) have a conspicuous coloration and feed exclusively on Brunfelsia uniflora (Solanaceae), that is rich in compounds of the secondary metabolismo These larvae were analyzed under several aspects to confirm if they are chemically defended. Survivorship data showed predation significantly affecting larval survival in natural habitat. Larvae chemical defenses are inefficient against invertebrate predators, such as the spider Lycosa erythr-ognatha and the ant Campónotus crassus (100% of predation), but it seems to be efficient against the mantid Oxyopsis saussuurei (reduction of prey manipulation time and predation in a second contact). To vertebrate predators, like the lizard Tropidurus itambere and the chick Gallus gallus, defense acts through conspicuous coloration and palatability. Predation by Gallus gallus was highest upon 1st ínstar larvae, suggesting an increase of unpalatability throughout development. Learning avoidance tests with Gallus gallus demonstrated that few contacts with distasteful and warning colored prey could make the predator reject visually Methona themisto larvae. Chicks visually rejected palatable larvae painted in the same color pattem of Methona themisto larvae confirming their ability to associate taste and color. Only dichloromethanic extracts tested with chicks showed significant rejection in relation to controls. These results confirm that Methona themisto larvae are chemical defended against visually oriented vertebrate predators
Mestrado
Mestre em Ecologia
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Aronsson, Marianne. "Colour patterns in warning displays." Doctoral thesis, Stockholms universitet, Zoologiska institutionen, 2012. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-75576.
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In aposematism a prey species use bright colours, often combined with a black contrasting pattern, to signal unprofitability as prey to potential predators. Although there are several different hypotheses about the presence of these internally contrasting patterns, there is little experimental evidence of any beneficial effects. In this thesis I have used bird predators and artificial prey signals to investigate if the contrasting internal patterns in warning displays may have evolved to increase signal efficacy, especially regarding the speed of avoidance learning. In paper I the relative importance of colour and pattern in avoidance learning was studied. The conclusion was that birds primarily attend to colour, not pattern, when learning the discrimination, which was further supported by the results in paper II-IV, all suggesting a secondary role of patterns. In paper II I show that predators may to some degree use patterns for discrimination, if they convey important information about prey quality. The predators showed a hierarchical way of learning warning colour components, where colour is learned to a higher degree than pattern. In paper III I investigate if internal contrasting patterns promote avoidance learning by increasing conspicuousness as prey-to-background contrast does. The study did not support this idea, as the presence of internal black patterns did not improve avoidance learning on a colour matching background. In paper IV, however, I show that the presence of many internal colour boundaries resulted in faster avoidance learning on a multi-coloured background, and predator generalization favoured more internal boundaries, while there was no effect of pattern regularity. From these studies I conclude that internal pattern contrasts may function to increase the efficacy of the warning colour, its salience, and as a means for aposematic prey to be discriminated from harmful mimics. However, the major finding is the importance of colour over pattern.At the time of the doctoral defence the following papers were unpublished and had a status as follows: Paper 2: Manuscript; Paper 4: Manuscript
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Lundberg, Katarina. "UR PRODUKTION." Thesis, Konstfack, Institutionen för Konst (K), 2017. http://urn.kb.se/resolve?urn=urn:nbn:se:konstfack:diva-5682.
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När det är mörkt tycker jag om att gå hem. Det är oftast utifrån mina nattliga vandringar jag producerar, samlar och ser samband då jag i ensam tystnad möter nya rum och konstellationer som uppstår och försvinner i staden. Jag fotograferar till blivande målningar, filmar eller tar objekt från platser för att använda i mitt arbete. Denna text koncentrerar sig främst kring de platser jag ser på, tankar kring dem och hur de överförs till att bli måleri.
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Dalbosco, Dell'Aglio Denise. "Behavioural and ecological interactions between Heliconius butterflies, their predators and host plants." Thesis, University of Cambridge, 2016. https://www.repository.cam.ac.uk/handle/1810/267756.
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Heliconius butterflies exhibit Müllerian mimicry, in which two or more unpalatable species share a mutual advantage from having a common conspicuous colour pattern. These tropical butterflies have impressive visual signals, which are under conflicting selection pressures, as they are used in choosing potential mates and defending against visual predators through aposematic coloration. As both selection pressures are likely to be strong, different elements of the signal might be adapted for different receivers. Here, I combine sensory ecology with behavioural ecology to explain Heliconius colours signals of different co-mimic pairs. I explore how mimicry in Heliconius is perceived both from the perspective of predators and conspecifics, using visual abilities of both butterflies and birds. The different visual sensitivities of avian predators, H. erato females and males make them to perceive Heliconius coloration in different ways. My work suggests that having the ability to see in the ultra-violet light range enables higher discrimination between co-mimics both for birds and butterflies. Heliconius warning colours transmit a consistent signal across time of the day and habitat in a tropical forest for avian vision. In contrast through Heliconius vision there is evidence that patterns are more conspicuous in their own habitats. All these traits could facilitate communication between co-mimics and reduce the cost of confusion in courtship while still maintaining the advantages of Müllerian mimicry against predation. I conducted a field experiment to show that attack rates on a novel distasteful butterfly reduced over time, suggesting that Heliconius wing colouration can enhance aversion among predators. Finally, I have shown that Heliconius butterflies use leaf shape as a cue to approach their host plants, demonstrating the potential for Heliconius to drive negative frequency dependent selection on the leaf shape of their Passiflora host plants. Overall these results highlight ecological interactions between Heliconius butterflies, their predators and host plants.
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Adamová, Dana. "Faktory ovlivňující variabilitu v reakcích sýkor (Paridae) vůči nové a aposematické kořisti." Doctoral thesis, 2016. http://www.nusl.cz/ntk/nusl-353569.
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Inter-specific and intra-specific variation in reactions towards novel and aposematic prey was found in several species of tits (Paridae). This Ph.D. thesis is focusing on various factors influencing reactions towards novel and aposematic prey in three European species of tits. We tested differences in exploration behaviour, neophobia, dietary conservatism, personality, age and experience as well as ability of avoidance learning and generalisation. We found no difference in exploration behaviour and in reaction towards novel prey in two different populations of great tits (Parus major). But the birds from the Finnish population were more neophobic than Czech birds, but they attacked aposematic firebug (Pyrrhocoris apterus) more often and faster than Czech birds. The difference can be explained by a different experience with local aposematic prey communities. Than we studied initial wariness in naive juveniles of great tits (P. major), coal tits (Periparus ater) and blue tits (Cyanistes caeruleus), and we tested how the initial wariness towards novel and aposematic prey can be deactivated by experience with palatable prey. Great tits and coal tits from experienced groups significantly decreased their neophobia towards both types of prey while blue tits did not change their strongly neophobic...
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MEJDA, Tomáš. "Reakce ptáků na invazní blánatku lipovou (Oxycarenus lavaterae)." Master's thesis, 2019. http://www.nusl.cz/ntk/nusl-396069.
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Oxycarenus lavaterae is species of Heteroptera and possessing pink blots on corium and distinctive, gleaming membranaceous wings. This appearance could correspond to the definition of a warning color. The design is similar to other coreoid Heteroptera, which live in the Czech Republic; though Oxycarenus lavaterae is a species originating from Mediterranean and quickly spreading north. In Czech Republic it is a new species and predators thus have only short experience with it.The information about chemical protection of Oxycarenus lavaterae is weak and the effect on predators has never been tested. The characteristic behaviour for this species is creating large aggregations, primarily at the time of hibernation. At that time, several thousands of individuals are gathered in apertures or at the surface of tree bark. The aggregation may enhance the warning appearance of this species. The aim of this study was to test the response of bird predators to the adult individuals of Oxycarenus lavaterae. Three species of insectivorous birds differing in the level of foraging and diet specialization was chosen as predator (namely - Great tit (Parus major), Blue tit (Cyanistes caeruleus), Eurasian blackcap (Sylvia atricapilla)). Unmodified individuals of Oxycarenus lavaterae were served to these predators. In the case of the Parus major, the aggregation of Oxycarenus lavaterae (about 100 pieces) was also presented to test the effect of gregarious behavior on the warning signal. This study showed that the Parus major and the Sylvia atricapilla attacked the individual Oxycarenus more often than the Cyanistes caeruleus showing high level of restraint. In experiments with aggregatedOxycarenus lavaterae Parus major attacked them less often than when presented solitarily. However, after eating some Oxycarenus lavaterae, the Parus major showed symptoms of disgust and loss of appetite.
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Bednářová, Hana. "Role aldehydů v multimodální výstražné signalizaci ploštic." Master's thesis, 2016. http://www.nusl.cz/ntk/nusl-351446.
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1 Abstract: Multimodal signaling is quite common in nature. Even if we focus only on signaling among prey and its predator, we can still find many examples of communication combining more than one modality (vision, hearing, smell, taste). This thesis is about multimodal warning visual and olfactory signaling between true bugs (Heteroptera) and their avian predators. Aldehydes are an important compound of repellent secretion of most true bug species. They are considered to have defence effects against predators. In our experiments, we tested the effect of aldehydes mixture on behaviour of predators - naive hand-reared and experienced wild-caught adult great tits (Parus major) - towards several kinds of prey - aposematic true bugs Pyrrhocoris apterus, nonaposematic true bugs Pyrrhocoris tibialis and red painted mealworms (Tenebrio molitor larvae). We were focusing on the effect of aldehydes on initial reaction, learning process and predator's memory. Aldehydes elicited innate wariness in naive hand- reared great tits towards aposematic P. apterus, but not towards P. tibialis. Therefore it seems possible, that aldehydes act as a signal of unpalatability for naive predators, but only in multimodal combination with visual warning signal. Similar effect of aldehydes was not found in experiments with wild-caught...
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Malečková, Dana. "Reakce ptačích predátorů na různé složky repelentní sekrece ploštic." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-312473.
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Aposematic species of true bugs (Heteroptera) have multimodal signalization, which warns potential predators. This signalization consists of optical (coloration), chemical (unpalatable or repugnant substance) and acoustic (stridulation) warning signals. The aim of this thesis was to test whether the selected chemical substances have antipredatory function towards avian predators. Antipredatory function is anticipated in the chemical substances that form the majority in secretion in many taxa of true bugs (aldehydes and tridecane). In experiments with wild-caught great tits (Parus major) and blue tits (Cyanistes caeruleus) we tested if chemical substances and age of birds have influence on the latency related to the first manipulation with the prey. It was found that both species of tits reacted aversively to the mixture of aldehydes (2-decenal, 2-octenal, 2-hexenal) and to the total secretion of metathoracic glands of Graphosoma lineatum, whereas the mixture of the aldehydes with tridecane did not have any effect. The effect of age was not significant. We also tested the influence of immediate experience with striated shieldbug Graphosoma lineatum on naive great tits and their reactions to the prey with olfactoric signal of the shieldbug. Additionally, we investigated whether tested chemicals cause...
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Raška, Jan. "Pavouci jako zdroje a příjemci antipredačních varovných signálů." Doctoral thesis, 2019. http://www.nusl.cz/ntk/nusl-404514.
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The introductory part of this thesis sums up the state of knowledge on aposematism and mimicry, the effect of aposematic and mimetic signals on spider predators, and cases when spiders do not receive but send such signals. Attachments of the thesis include four original manuscripts. In the first study, we presented jumping spiders (Evarcha arcuata, Salticidae) with different colour forms (red-and-black, yellow-and-black, white-and-black) of the firebug (Pyrrhocoris apterus, Pyrrhocoridae). Our goal was to compare reactions of the spiders to various intensity of aposematic signalization, expecting red-and-black coloration to have the strongest effect. Aversive learning of all colour forms was equally effective, but generalization of the learned avoidance to other colour forms was more effective after switch from less (white-and-black, yellow-and-black) to more (red-and-black) conspicuously coloured prey. When tested the next day, avoidance of the white-and-black prey got mostly forgotten. In the second study, we assessed little studied sensitivity of spiders to smells of unpalatable prey. After jumping spiders learned to avoid firebugs, most of them avoided the firebug smell, showing their sensitivity not only to optical, but also to chemical part of signalization of the unpalatable prey. In the...
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Binderová, Jana. "Účinnost multimodální výstražné signalizace Tritomegas sexmaculatus vůči ptačím predátorům." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-296667.
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Aposematic animals advertise their defensive mechanisms to potential predators using warning signals. Signalling through more than one sensory pathway is called multimodal warning display. Most experimental studies of aposematism have been focused on the effect of a particular warning signal rather than on importance of multimodal signalling. Focusing on the multimodal signalling of real prey is the best way how to understand its effect in nature. The present study is focused on comparing the effect of multimodal warning display of insect prey with its particular warning signals on two species of bird predators. Multimodal warning signalisation of the burrowing bug, Tritomegas sexmaculatus consists of visual (black and white coloration), chemical (odour, possibly taste) and acoustic (stridulation) signals. We compared reactions of wild-caught great tit (Parus major) and blue tit (Cyanistes caeruleus) to three types of bugs with different warning displays. The non-manipulated bugs displayed multimodally, the brown painted bugs had their warning coloration manipulated and the dealatized bugs couldn't emit acoustic signals. The wild-caught birds of both species avoided all types of bugs. In an experiment with naive hand reared great tits we compared their reactions to non-manipulated and dealatized bugs. Naive...
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VAŇKÁTOVÁ, Martina. "Reakce na zbarvení ruměnice pospolné (\kur{Pyrrhocoris apterus}) a jeho varianty u lidí." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-81823.
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So far, nobody examined a human reaction on aposematic signals. I used red firebug's coloration and its modifications in color and pattern for testing the human reactions. People showed refusing reaction on white color and on some types of eye spots. There is a big difference between reactions on red color and black color in different human groups. This needs further research.
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VESELÝ, Petr. "Rozlišování nevhodné kořisti ptačími predátory." Doctoral thesis, 2010. http://www.nusl.cz/ntk/nusl-45591.
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The present PhD thesis comprises four published research papers and two manuscripts in preparation dealing with importace of particular parts of the warning signal in protection of insect prey against avian predators.
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BENEŠ, Josef. "Effect of the search image on the lizard ability to reveal a Batesian mimic." Master's thesis, 2016. http://www.nusl.cz/ntk/nusl-204442.
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The effect of the search image on the ability of hand reared skinks (Chalcides sexlineatus) to reveal a "fake" Batesian mimic was tested with respect to their previous experience with palatable experimental prey (Guyana spotted cockroach Blaptica dubia) which served as a motivational prey as well as midsized mealworm beetle larvae (Tenebrio molitor). The red firebug (Pyrrhocoris apterus) was used as an aposematic model.
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Bělová, Magdalena. "Role sociálního učení při vytváření averze vůči aposematické kořisti u ptačích predátorů." Master's thesis, 2018. http://www.nusl.cz/ntk/nusl-388367.
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Social learning is a topic of many studies. We tested the effect of social learning on the acquisition of avoidance against aposematic prey. We have chosen wild-caught adult and naive hand-reared juvenile great tits (Parus major) as a model predator species, because their individual avoidance learnig of aposematic prey is well-studied. We used red and green paper dummies of bugs with a mealworm (Tenebrio molitor) stuck underneath as an artificial prey. Mealworms were soaked in water or in bitter-tasting solution of quinine. We used two types of conspecific demonstrators - naive birds that showed aversive reactions while tasting an unpalatable prey and experienced birds that were trained not to handle the unpalatable pray at all. We compared effects of both demonstrators on discrimination learning and we tested whether these effects differ in adult and juvenile birds. Observing an experienced demonstrator had an effect on the performance of observers at the beginning of learning process. The observers did not reject the unpalatable prey completely, but the number of trials in which they correctly chose the palatable prey was higher in comparison with birds that observed naive demonstrators and birds from the control group with no demonstrator. Latencies to handle the unpalatable prey in the first...
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Beranová, Eliška. "Explorace, neofobie a potravní konzervatismus u sýkor." Master's thesis, 2012. http://www.nusl.cz/ntk/nusl-306665.
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Neophobia and exploratory behaviour are two processes applied in great measure in birds' reactions towards novel stimuli. The specific demonstration of these two processes may differ between different species of birds as well as within them. We compared neophobia and exploratory behaviour in two species of tits (Paridae). Adult Great tits (Parus major) and Blue tits (Cyanistes caeruleus) did not differ neither in exploring novel environment and novel object nor in neophobia towards novel object near food. We have found great differences between juveniles of these two species. Juvenile Blue tits were more neophobic towards both novel objects. Age, sex and personality affected some differences within tested species. We tested whether there exist any differences in reactions towards novel food between and within species. We used red painted mealworm (larvae of Tenebrio molitor), house cricket (Acheta domestica) and aposematic bug (Pyrrhocoris apterus) as novel food. Adult wild-caught tits with plentiful experience with various feeds did not differ in reaction towards these types of novel food. In contrast hand-reared juvenile tits differed quite a lot. Juvenile Blue tits were more neophobic than juvenile Great tits towards all three types of novel food. We found dieraty conservatism, phenomenon...
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DOLENSKÁ, Michaela. "Aposematismus vybraných druhů slunéček (Coccinellidae): testování vlivu zbarvení a dalších ochranných prvků na chování ptačího predátora sýkory koňadry (\kur{Parus major})." Master's thesis, 2006. http://www.nusl.cz/ntk/nusl-43067.
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Chalušová, Kateřina. "Reakce ptáků na ploštice ze skupiny Lygaeoidea: efektivita chemické obrany." Master's thesis, 2018. http://www.nusl.cz/ntk/nusl-388399.
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By warning signalling prey advertises its unpalatability to the predators. Typical examples are true bugs (Heteroptera) combining optical and chemical signals. The aim of this study was to find out the effectiveness of chemical defence against wild-caught adults of great tits (Parus major) and blue tits (Cyanistes caeruleus) and towards hand-reared juveniles of great tits. The tested prey were adults and larvae of two invasive species of genus Oxycarenus (Heteroptera: Oxycarenidae) (aposematic O. lavaterae, non-aposematic O. hyalinipennis), adults of Horvathiolus superbus (Heteroptera: Lygaeidae) and crickets (Gryllus assimilis) as a control prey. We were focusing on the influence of seed bugs to the initial reaction, the learning process and to the displays of discomfort behaviour in tits. Reactions affected by the tit species, age and sex were compared in adults. Juveniles were divided into two independent experimental groups, one group was offered adults of genus Oxycarenus, the second was offered sunflower (Helianthus sp.) or Digitalis sp. seed fed adults of H. superbus. The first bug offered did not elicit an initial aversive reaction in tits, but birds reacted aversively to the bugs after having further handling experience. All juveniles, contrary to the adult tits, attacked at least one bug...
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Raška, Jan. "Reakce skákavky Evarcha arcuata na aposematické ploštice." Master's thesis, 2011. http://www.nusl.cz/ntk/nusl-312855.
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Jan Raška: Reactions of the jumping spider Evarcha arcuata to aposematic true bugs Abstract: This paper studies the effect of qualities of a prey on predatory behaviour of Evarcha arcuata (Araneae: Salticidae). Naturally coloured aposematic larveae of Pyrrhocoris apterus have been compared to two types of prey: 1) to identically coloured but in defensive secretion different larvae of Scantius aegyptius, and 2) differently coloured larvae of white mutants of P. apterus. The defensive secretion of S. aegyptius has been found less effective in the first interaction with predator than that of P. apterus, however, after several trials the difference of reactions of the spider has not been noticeable. When changed the species of prey, E. arcuata has symmetrically and considerably generalised between the two species. Significant difference has been established in memory test - while P. apterus has been avoided even after one day, S. aegyptius has been attacked as thought the spiders were naive. The learning sequence has been similar in both colour forms of P. apterus; the generalisation of the two colours has been symetrical as well. Both colour forms succeeded in memory test (e.g. spiders have proven difference in comparison with the naive ones), however, white mutants have been successfully attacked...
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Pipek, Pavel. "Antipredační funkce fulgurace u ploštic (na příkladu druhu Coreus marginatus)." Master's thesis, 2010. http://www.nusl.cz/ntk/nusl-296220.
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1 Abstract Aim of the present study was to test antipredatory function of fulguration (or flash display), which means sudden exposition of conspicous body part on otherwise cryptic animal during escape. Adult squash bugs (Coreus marginatus; Heteroptera) were used as model prey, while as model predator served two species of passerine birds - blue tit (Cyanistes caerulus) and great tit (Parus major). Three approaches were undertaken. Test of palatability should have assessed the efficiency of squash bug chemical defence against bird predators. Experiment was carried out in experimental cage without interference of experimenter and without occurrence of fulguration. The results show that chemical defense of squash bug is less efficient than defense of other species of true bugs (Pyrrhocoris apterus, Graphosoma lineatum) and that the efficiency differs between two generations of squash bugs. In the test of efficiency of fulguration, the prey was forced by experimenter to fly in response to bird attack. Blue tits attacked the immobile prey more often than the flying and fulgurating one, but the same relation wasn't significant with great tits. The latencies of birds' returns to the bugs that landed after fulguration wasn't influenced by colour of the bugs' abdomen. Third experiment consisted of computer...
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TESAŘOVÁ, Monika. "Role osobnosti v ptačí reakci na výstražně zbarvenou kořist." Master's thesis, 2008. http://www.nusl.cz/ntk/nusl-44055.
Full textAbstract:
Personality and individual differences in reactions of the Great tit to aposematic prey were investigated. The aim of this study was to assess differences in personality of forty Great tits and find out possible correlation to the reactions of these birds to aposematic prey, the fifth larval instar of firebug Pyrrhocoris apterus.
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Kuklová, Lucia. "Faktory ovlivňující efektivitu aposematických signálů vůči ptačím predátorům." Doctoral thesis, 2021. http://www.nusl.cz/ntk/nusl-446333.
Full textAbstract:
This thesis focuses on various factors affecting effectiveness of aposematic signals against avian predators. Adult, wild-caught as well as hand-reared juvenile great tits (Parus major) were used as predators in the experiments. The thesis consists of the following four studies. In the first study, we compared the reactions of great tits from two geographically distant populations toward aposematic firebugs (Pyrrhocoris apterus) and their non-aposematic artificially made colour variant. The birds from the Bohemian population mostly avoided aposematic firebugs and attacked non-aposematic variant. Finnish birds, which lacked experience with firebugs from their natural environment, were less hesitant to attack both firebug colour forms. Although the Bohemian birds avoided the aposematic prey variant, they were not more neophobic than Finnish birds. We conclude that the geographic differences in reactions of the birds to aposematic prey can be explained by a different population-specific experience of the birds with local aposematic prey communities. In the second study, we compared effectiveness of two chemical defence strategies in leaf beetle larvae (Chrysomela lapponica) against great tits. The birds avoided larvae devoid of external secretions after the first attack, which indicates the presence...
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Marešová, Jana. "Lidské preference živočišných druhů a jejich vliv na druhovou ochranu." Doctoral thesis, 2012. http://www.nusl.cz/ntk/nusl-312190.
Full textAbstract:
The dissertation thesis deals with human aesthetic preference to other species and its anthropological and conservation aspect. The aesthetic preference to animal species has rarely been systematically studied before and quantitative analyses, especially on a fine taxonomic scale did not exist. On the other hand, it was known that attractive species often receive more support for their conservation. From these simple facts rose the idea to test human aesthetic preference to snake species (and consequently to species across major vertebrate taxa) and use this quantified preference to explain the conservation effort devoted to captive breeding worldwide (measured as size of zoo populations). We confirmed that the perceived attractiveness (preference and/or species' body size) succesfully predicts the size of zoo populations across mammal, bird and reptile taxa. On contrary, we found no effect of the IUCN listing of the species. To find out whether we work with Czech students' preference only or we may generalize to other populations, we carried out the same experiment to determine human preference to boas and pythons in eight cultures of five continents. Despite profound differences of the studied ethnics, we revealed a considerable agreement. Moreover, we found an agreement between pre-school...
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Darst, Catherine Rachel 1978. "Evolutionary and ecological dynamics of aposematism and mimicry in poison frogs." 2006. http://hdl.handle.net/2152/13000.
Full text
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Santos, Juan Carlos. "Phylogeography and the evolution of correlated traits under multiple origins of aposematism in the poison frog family." 2009. http://hdl.handle.net/2152/6602.
Full textAbstract:
Living organisms are under selection not only for one, but also for several
inheritable characters at the same time. Well-sampled and well-supported
phylogenies are necessary for the studies of character evolution and their history.
The poison frogs (Dendrobatidae) are a well-known example of aposematism in
anurans. They include ~270 species of Neotropical frogs with aposematic (toxic
and conspicuous) and non-defended (palatable and cryptic) species. The origin of
aposematism in poison frogs is puzzling, because of its predicted low probability
of establishment due to the prey's increased conspicuousness. Previous studies
suggested a single origin of toxicity and warning coloration. By expanding taxon
sampling of the group, I reexamined the phylogenetic correlation between the
origins of toxicity and warning coloration. I found four or five independent
origins of aposematism; by using simulations, I rejected hypotheses of one, two, or three origins of aposematism (P < 0.002). I also found that diet specialization is
linked with the evolution of aposematism and has evolved independently at least
two times. Poison frogs are endemic to the Neotropic, which is one of the Earth's
largest reservoir of biodiversity. I reconstructed the biogeography of the poison
frog clade and rejected an Amazonian center-of-origin in favor of a model
expanding over the Neotropics. I inferred 14 dispersals into and 18 out of
Amazonia to adjacent regions; the Andes were the major source of dispersals into
Amazonia. Significant percentage of dendrobatid diversity in Amazonia and
Chocó resulted from repeated immigrations, with radiations at <10.0 million years
ago. In contrast, the Andes, Venezuelan Highlands, and Guiana Shield have
undergone extended in situ diversification at near constant rate since the
Oligocene. Poison frogs have significant variation on their physiological
characteristics. I measured resting and active metabolic rates of 54 species. I
traced metabolic measurements along aposematism, diet specialization, molecular
rates, and body mass. I found a synergistic and co-adapted functionality of active
metabolic rates with all previous traits that is perhaps the consequence of the
increase in complexity in most biological systems. My thesis has expanded the
knowledge of the biology, phylogenetic history, and biogeography of the poison
frogs.text
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Brandley, Nicholas. "Ultimate Causes and Consequences of Coloration in North American Black Widows." Diss., 2015. http://hdl.handle.net/10161/9954.
Full textAbstract:
Researchers have long assumed that black widow coloration functions as a warning signal to avian predators. However adult female black widow coloration does not resemble typical warning coloration in two distinct ways. First, black widows are less colorful than most other documented aposematic species. Second, the hourglass shape of an adult female varies both between species and within a site. Here I examine the ultimate causes and consequences of North American black widow coloration.
In chapter two I present data that suggest that black widow coloration not only functions as an aposematic signal to avian predators, but has also been selected to be inconspicuous to insect prey. In choice experiments with wild birds, I found that the red-and-black coloration of black widows deters potential predators: wild birds were ~3 times less likely to attack a black widow model with a red hourglass than one without. Using visual-system appropriate models, I also found that a black widow's red-and-black color combo is more apparent to a typical bird than typical insect (Euclidean color distance ~2.2 times greater for birds than insects). Additionally, an ancestral reconstruction revealed that red dorsal coloration is ancestral in black widows and that at some point some North American black widows lost their red dorsal coloration (while maintaining the ventral hourglass). Behaviorally, differences in red dorsal coloration between two North American species are accompanied by differences in microhabitat that affects how often a bird will view a black widow's dorsal region. All observations are consistent with a cost-benefit tradeoff of being conspicuous to potential predators while being inconspicuous to prey. I suggest that avoiding detection by prey --- combined with Müllerian mimicry --- may help explain why red-and-black aposematic signals occur frequently in nature.
In chapter three, I examine the variation in hourglass shape. Classical aposematic theory predicts near uniformity in warning signal appearance because a uniform signal is easier to learn to avoid than a variable signal. However the shape of the hourglass of North American black widows appears to vary both within and between sites in ways that are inconsistent with classical aposematic theory. Using 133 black widows of three different species from nine sites across the United States, I quantified the variation in hourglass shape and examined how Müllerian mimicry, species type, and condition each influenced hourglass shape. A principle components analysis revealed that 84.5% of the variation in hourglass shape can be explained by principle components 1, 2, and 3, which corresponded to hourglass size (PC1), the separation between hourglass parts (PC2), and the slenderness of the hourglass (PC3). Both a black widow's condition and species significantly predicted hourglass shape; however I found no support for localized Müllerian mimicry within different geographical regions. My results suggest a relaxed role for selection on hourglass shape. I discuss several hypotheses that could explain the variation in hourglass morphology including that potential predators may avoid any red markings rather than an exact shape (categorical rather than continuous perception).
In chapter four I expand on my work from chapter two to examine the eavesdropper's perspective on private communication channels. Private communication may benefit signalers by reducing the costs imposed by potential eavesdroppers such as parasites, predators, prey, or rivals. It is likely that private communication channels are influenced by the evolution of signalers, intended receivers, and potential eavesdroppers, but most studies only examine how private communication benefits signalers. Here, I address this shortcoming by examining visual private communication from a potential eavesdropper's perspective. Specifically, I ask if a signaler would face fitness consequences if a potential eavesdropper could detect its signal more clearly. By integrating studies on private communication with those on the evolution of vision, I suggest that published studies find few taxon-based constraints that could keep potential eavesdroppers from detecting most hypothesized forms of visual private communication. However, I find that private signals may persist over evolutionary time if the benefits of detecting a particular signal do not outweigh the functional costs a potential eavesdropper would suffer from evolving the ability to detect it.
Dissertation
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"Iridescent, Distasteful, and Blue: Effectiveness of Short-Wavelength, Iridescent Coloration as a Warning Signal in the Pipevine Swallowtail Butterfly (Battus philenor)." Doctoral diss., 2015. http://hdl.handle.net/2286/R.I.29629.
Full textAbstract:
abstract: Warning coloration deters predators from attacking prey that are defended, usually by being distasteful, toxic, or otherwise costly for predators to pursue and consume. Predators may have an innate response to warning colors or learn to associate them with a defense through trial and error. In general, predators should select for warning signals that are easy to learn and recognize. Previous research demonstrates long-wavelength colors (e.g. red and yellow) are effective because they are readily detected and learned. However, a number of defended animals display short-wavelength coloration (e.g. blue and violet), such as the pipevine swallowtail butterfly (Battus philenor). The role of blue coloration in warning signals had not previously been explicitly tested. My research showed in laboratory experiments that curve-billed thrashers (Toxostoma curvirostre) and Gambel's quail (Callipepla gambelii) can learn and recognize the iridescent blue of B. philenor as a warning signal and that it is innately avoided. I tested the attack rates of these colors in the field and blue was not as effective as orange. I concluded that blue colors may function as warning signals, but the effectiveness is likely dependent on the context and predator.
Blue colors are often iridescent in nature and the effect of iridescence on warning signal function was unknown. I reared B. philenor larvae under varied food deprivation treatments. Iridescent colors did not have more variation than pigment-based colors under these conditions; variation which could affect predator learning. Learning could also be affected by changes in appearance, as iridescent colors change in both hue and brightness as the angle of illuminating light and viewer change in relation to the color surface. Iridescent colors can also be much brighter than pigment-based colors and iridescent animals can statically display different hues. I tested these potential effects on warning signal learning by domestic chickens (Gallus gallus domesticus) and found that variation due to the directionality of iridescence and a brighter warning signal did not influence learning. However, blue-violet was learned more readily than blue-green. These experiments revealed that the directionality of iridescent coloration does not likely negatively affect its potential effectiveness as a warning signal.Dissertation/Thesis
Doctoral Dissertation Biology 2015
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Skoumalová, Žaneta. "Faktory ovlivňující paměť ptačích predátorů pro aposematické signály." Master's thesis, 2018. http://www.nusl.cz/ntk/nusl-380189.
Full textAbstract:
The ability to memorize and recognize edible prey from inedible prey is essential for an individuals survival. Many species use aposematic signals for their defense. These are most often represented by distinctive colors or contrast patterns. The aim of this study was to find out in which time the memory consolidation for aposematic pray is achieved and if color or pattern increase its memorability. The choosen model species was the Great tit (Parus major). The comparision was done between handreared naïve birds and wild-caught adults of different age and sex. During the discriminatory task of consolidation experiment, birds were simultaneously presented with palatable and unpalatable prey in the form of paper dummies of bugs, differing in color (red versus green). The birds were divided into three groups with a different interval (0, 1 or 3 hours) for consolidation. The results of consolidation test show that adult birds were more successfull in solving the task than juvenile birds. The only difference between the experimental groups was that the group with one-hour interval achieved better results than other groups. The effect of color of palatable and unpalatable prey on discrimination learning was also found only in adults. Memorability of warning signals was tested using paper bugs of...
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Chouteau, Mathieu. "Sélection et polymorphisme chez des grenouilles mimétiques du Pérou (Dendrobatidae)." Thèse, 2011. http://hdl.handle.net/1866/5514.
Full textAbstract:
La diversification des signaux aposématiques dans un cadre de mimétisme müllérien est un phénomène intrigant. Alors que la théorie relative à l'aposématisme et au mimétisme suggère l'évolution vers un signal aposématique unique, d'impressionnantes variations peuvent être observées entre les populations, et cela à petite échelle spatiale. Il a été supposé que la variation spatiale des pressions de sélection engendrées par différents prédateurs puisse être à l'origine de ce phénomène.
Afin de tester cette hypothèse, nous avons étudié la transition entre deux systèmes géographiques caractérisés par des patrons aposématiques distincts chez des grenouilles mimétiques et toxiques du nord du Pérou (Dendrobatidae) en combinant les outils de génétique des populations aux outils écologiques. Dans chacun de ces systèmes, Ranitomeya imitator vit en sympatrie avec R. ventrimaculata ou R. variabilis. Il s'agit du principal exemple empirique suggérant que dans un cadre de mimétisme müllérien, il n'y a pas convergence des signaux aposématiques des deux espèces, mais plutôt convergence unidirectionnelle où R. imitator, étant polymorphe, imite des espèces monomorphes avec lesquelles elle est sympatrique.
Premièrement, les résultats réfutent les prémisses qui suggèrent que R. imitator converge vers le signal aposématique d’une autre espèce. La haute similarité génétique entre les espèces modèles suggère qu'elles ont divergé plus récemment que les populations de R. imitator ou qu'elles sont encore connectées par du flux génique. Ces résultats indiquent que ces espèces ont été identifiées à tort comme des espèces différentes. De fait, l'identification de l'espèce imitatrice basée sur la variabilité phénotypique est invalidée dans ce système puisque R. imitator et R. variabilis/ventrimaculata démontrent la même variabilité.
Deuxièmement, nos résultats démontrent que la prédation varie spatialement, autant en intensité qu'en direction, créant ainsi un paysage hétérogène de pressions de sélection. Ainsi, de fortes pressions de prédation stabilisatrice permettent le maintien de l'organisation géographique de différents signaux aposématiques et expliquent l'uniformité de ces signaux ainsi que les relations mimétiques. Par contre, le relâchement temporaire des pressions de prédation permet l'apparition de nouveaux phénotypes aposématiques via les processus évolutifs neutres, conduisant à un haut polymorphisme au niveau de ces populations. L'interaction de ces modes sélectifs nous a permis de démontrer pour la première fois comment la théorie évolutive de Wright (shifting balance theory) permet la diversification adaptative dans un système naturel.
Pour conclure, cette étude a permis de mettre en évidence à quel point les systèmes de mimétisme müllérien peuvent être dynamiques. L'alternance spatiale entre les processus évolutifs neutres et la sélection naturelle permet l'émergence de nouveaux phénotypes aposématiques à une échelle locale, ainsi que l'apparition d'une organisation géographique des signaux d'avertissement et des relations de mimétisme müllérien.The diversification of aposematic signals in Müllerian mimicry systems is a puzzling phenomenon. Although aposematism and mimicry are expected to promote uniformity in warning signals, impressive variations may be observed among populations at relatively small spatial scales. It has been suggested that spatial variation in selective pressures caused by predators might be responsible for this phenomenon. In order to test this hypothesis, we studied the transition in the aposematic signals of the mimetic poison-dart frogs of Northern Peru (Dendrobatidae) between two geographical systems characterized by distinct aposematic signals. This was done by combining population genetics and ecological tools. In both systems, Ranitomeya imitator is sympatric with either R. ventrimaculata or R. variabilis. This system is recognized as a rare example in support of the hypothesis for advergence: R. imitator, which is polymorphic, is believed to mimic distinct sympatric monomorphic model species. However, our results do not support the hypothesis for advergence of the aposematic signals by R. imitator. The genetic similarity between the model species suggests that they have diverged more recently than R. imitator populations or that they are still connected by gene flow. These results indicate that these species were misidentified as being different species. As such, the identification of the mimetic species based on phenotypic variability is invalidated in this system, since R. imitator is as variable as R. variabilis/ventrimaculata. Also, our results demonstrate that predation pressure is spatially variable, in both intensity and direction, thus creating a heterogeneous selective landscape. As such, strong and directed stabilizing selective pressures maintain the geographic organisation of aposematic signals and explain phenotypic uniformity and mimetic relationships. Relaxation of these selective pressures enables for the appearance of novel aposematic phenotypes and promotes high phenotypic variability via neutral evolutionary processes. The interaction between these selective regimes has enabled us to demonstrate, and this for the first time, how the Wright’s shifting balance theory of evolution may promote adaptive diversification in a natural system. In conclusion, this study highlights just how dynamic Müllerian mimicry systems can be. The interplay between neutral evolutionary processes and natural selection enables for the predominance of novel aposematic phenotypes at a local scale, and the geographical organisation of warning signals and Müllerian relationships.
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Crothers, Laura Rose. "Intrasexual selection and warning color evolution in an aposematic poison dart frog." Thesis, 2014. http://hdl.handle.net/2152/30933.
Full textAbstract:
Flamboyant colors are widespread throughout the animal kingdom. While many of these traits arise through sexual selection, bright coloration can also evolve through natural selection. Many aposematic species, for example, use conspicuous warning coloration to communicate their noxiousness to predators. Recent research suggests these signals can also function in the context of mate choice. Studies of warning color evolution can therefore provide new insights into how the interplay of natural and sexual selection impact the trajectory of conspicuous signal evolution. For my dissertation, I investigated the potential for male-male competition to impact the warning color evolution of a species of poison frog. I focused my work on an exceptionally bright and toxic population of the strawberry poison frog (Oophaga pumilio) where males are brighter than females, a classic signature of sexual selection. In Chapter 1, I used theoretical models of predator and frog visual systems to determine which can see the variation in bright warning coloration within this population. I found that birds, the presumed major predator, likely cannot see this variation, indicating that sexual selection can work under the radar of predators in this species. In Chapter 2, I tested the aggressive responses of males using a two-way choice paradigm that manipulated the perceived brightness of stimulus males. I found that males directed more of their behaviors to bright stimulus frogs, and brighter focal frogs more readily approached stimuli and directed more of their attention to the brighter rival. In Chapter 3, I tested the outcomes of dyadic interactions between males of varying brightness and observed male reactions to simulated intruders in their territories. I found that brighter males initiated aggressive interactions with rivals more readily, and brightness asymmetries between males settled interactions in a way that is consistent with classic hypotheses about male sexual signals. In Chapter 4 I sought to describe physiological correlates of male warning color brightness. While male brightness did not co-vary with classic measures of body condition (circulating testosterone and skin carotenoids), it did correlate with toxins sequestered from the diet and thus appears to be a reliable signal of toxicity in this population.text