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

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.

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.

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.

<p>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. </p><p>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.</p><p>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).</p><p>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.</p> / Dissertation

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...

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.

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. / <strong><em></em></strong><em></em><em></em>At  the time of the doctoral defence the following papers were unpublished and had a status as follows: Paper 2: Manuscript; Paper 4: Manuscript<strong><em> </em></strong>

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

Orientador: Jose Roberto Trigo / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-10T19:03:33Z (GMT). No. of bitstreams: 1 Massuda_KamilaFerreira_M.pdf: 3824014 bytes, checksum: d4db5cb4afb22e7d40b4afc3d0677236 (MD5) Previous issue date: 2008 / 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