Submitted by Valquíria Barbieri (kikibarbi@hotmail.com) on 2018-04-09T21:08:02Z No. of bitstreams: 1 DISS_2014_Angélica Francisca Mendes Mamede.pdf: 690362 bytes, checksum: 992dd831bb86f670485b28ddc3c8df3c (MD5) / Approved for entry into archive by Jordan (jordanbiblio@gmail.com) on 2018-04-26T16:45:41Z (GMT) No. of bitstreams: 1 DISS_2014_Angélica Francisca Mendes Mamede.pdf: 690362 bytes, checksum: 992dd831bb86f670485b28ddc3c8df3c (MD5) / Made available in DSpace on 2018-04-26T16:45:41Z (GMT). No. of bitstreams: 1 DISS_2014_Angélica Francisca Mendes Mamede.pdf: 690362 bytes, checksum: 992dd831bb86f670485b28ddc3c8df3c (MD5) Previous issue date: 2014-03-13 / CNPq / A variação no uso de recurso é muito comum e pode ocorrer de diferentes formas dentro de uma população natural. Dentre essas se destacam a exploração de recursos diferenciada entre machos e fêmeas, jovens e adultos, ou pode estar relacionada à mudança na morfologia em resposta ao uso de recurso e especialização individual (essa por sua vez pode ser afetada pela competição intra ou interespecífica). Desse modo o objetivo desse trabalho é descrever o padrão de uso de recurso alimentar dentro de uma população do peixe jeju (Hoplerythrinus unitaeniatus), um peixe predador comum em ambientes lênticos, na planície de inundação do Pantanal. As coletas foram realizadas na planície de inundação localizada na região do Pantanal de Poconé nos anos de 2009, 2010 e 2011. De cada indivíduo foram tomadas medidas morfológicas, tiveram seu sexo determinado e o estomago retirado. Os itens alimentares de H. unitaeniatus e seu possível competidor Hoplias malabaricus foram identificados. Para quantificação foi utilizado o método numérico. Verifiquei se machos e fêmeas, e/ou jovens e adultos (classificados segundo estimativa de primeira maturação) e/ou variações na morfologia estavam relacionadas à composição da dieta dentro dessa população através de uma PERMANOVA. Então calculei o grau de especialização individual na população (IS) e o aninhamento (NODF), separadamente para grupos que diferiam na dieta. Utilizei uma PCA para reduzir a dimensionalidade dos dados de cobertura vegetal, para então saber se existiu efeito da competição intra ou interespecífica e cobertura vegetal no IS através de uma regressão multipla. Foram analisados os conteúdos estomacais de 145 exemplares de H. unitaeniatus: 56 machos (CP variando entre 49,02 e 200,22 mm) e 89 fêmeas (CP variando entre 64,13 e 204,50mm). O comprimento médio da primeira maturação estimado foi de 105,8 mm. Desta forma, 82 indivíduos foram classificados como jovens e 53 como adultos. Os itens alimentares foram divididos em 22 categorias. Machos e fêmeas não diferiram na composição de recursos utilizados (pseudo-F1,143=1,46; p= 0,14). No entanto, a composição da dieta diferiu entre jovens e adultos (pseudo-F1,143= 5,26; p<0,01). Quando confrontados com a composição da dieta, encontramos relação entre a variação na dieta relacionada à morfologia (eixo 2, pseudo-F1,142=2,07, p<0,01; eixo 3, pseudo-F1,142= 0,57, p=0,87). De forma geral, a amplitude de especialização individual dentro desta população variou entre 0,22 e 0,62 e foi significativa somente na minoria dos casos. O aninhamento só foi significativo em dois casos, e variou entre 10 e 60,83. O modelo geral de regressão múltipla entre o IS e a abundância de jeju e de traíra e os eixos da PCA de cobertura vegetal, representou 12,6% da variação encontrada no IS e não foi significativo (F4,9= 1,47; R²ajustado=0,126; p= 0,29). O IS não foi afetado pela abundância de jejus (p= 0,12), pela abundância de traíra (p= 0,53) e nem pela cobertura vegetal (eixo 1, p= 0,94; eixo 2, p= 0,6). Em síntese, a população de Hoplerythrinus unitaeniatus da planície de inundação do Pantanal apresentou uma tendência em ter especialização individual em poucos casos, esta por sua vez não foi influenciada por interações competitivas. Também encontrei variação intrapopulacional no uso do recurso explicada pela ontogenia e por variações morfológicas. / The variation in resource usage is very common and can occur in different ways in a natural population. Among these, I highlight the differentiated exploitation of resources between males and females, young and old, or can be related to change in morphology in response to resource usage and individual specialization (that in turn can be affected by intra-or interspecific competition). Thus the aim of this study is to describe the standard of food resources usege within a population of jeju fish (Hoplerythrinus unitaeniatus), a predator fish common in lentic environments) on the floodplain of the Pantanal. The collections were made in the floodplain located in the Pantanal region of Poconé in the years 2009, 2010 and 2011. The measures of morphology of each individual were taken and they had their sex determined and their stomach removed. The food itens of H. unitaeniatus and its possible competitor Hoplias malabaricus were identified. To quantify the numerical method was used. I checked if males and females, and/or adults (classified according to estimate of first maturity), and/or variations in morphology were related to the composition of the diet within that population through a PERMANOVA. Then I calculated the degree of individual specialization in the population (IS) and nestedness (NODF), separately for groups that differed in the diet. I used a PCA to reduce the dimensionality of the data of vegetation cover, and then whether there was effect of intra and interspecific competition or vegetation cover in IS through a multiple regression. The food itens of 145 especims of H. uniteniatus were analized: 56 males (Standard Length between 49.02 and 200.22 mm) and 89 females (SL between 64.13 and 204.50mm). The average length of the first maturation estimated is 105.8 mm. Thus, 82 individuals were classified as young and 53 as adults. The food itens were divided into 22 categories. Males and females did not differ in the composition of resource used (pseudo-F1.143=1.46; p= 0.14). However, diet composition differed between young fishes and adults (pseudo-F1.143= 5.26; p<0.01). When confronted with the composition of the diet, we found relashionship between variation in diet linked to morphology (axis 2, pseudo-F1.142=2.07, p<0.01; exis 3, pseudo-F1.142= 0.57, p=0.87). In general, the amplitude of individual specialization within this population ranged from 0.22 and 0.61 and was significant only in a minority of cases. The nestedness was significant only in two cases, and range between 10 and 60.83. The general model of multiple regression between the IS and the abundance of jeju and traíra and the PCA axes of vegetal cover, represented 12.6% of the variation found in the IS and was not significant (F4.9= 1.47; R²adjusted=0.126; p= 0.29). The IS was not affected by the abundance of jeju (p= 0.12), by the abundance of traíra (p= 0.53) and not by the vegetation cover (axis 1, p= 0.94; axis 2, p= 0.6). In summary, the population of Hoplerythrinus unitaeniatus of floodplain of Pantanal, presented a tendency to have individual specialization in a few cases, this turn was not influenced by competitive interactions. I also found intrapopulation variation in resource use explained by ontogeny and morphological variations.

Orientadores: Sergio Furtado dos Reis, Marcio Silva Araujo. / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-11T20:53:34Z (GMT). No. of bitstreams: 1 Costa_JoaoCarlosLopes_M.pdf: 677158 bytes, checksum: b1c8a350aeb6b46bf7f5c1573c624dec (MD5) Previous issue date: 2008 / Resumo: A dieta é um dos principais atributos do nicho ecológico de qualquer espécie animal. Geralmente nos estudos ecológicos os indivíduos de uma população são considerados ecologicamente equivalentes em relação ao uso de recurso. Contudo, esta abordagem tem se mostrada inadequada na descrição da utilização de recurso para várias espécies, como demonstrado por dados empíricos. A variação intrapopulacional pode ser ocasionada por fatores exógenos ou fenômenos endógenos ocasionados pelas diferenças sexuais e/ou ontogenéticas. Além disso, indivíduos pertencentes à mesma classe etária, ao mesmo sexo e dentro da mesma localidade podem também exibir variação no nicho. Esse fenômeno é denominado de "especialização individual" e sua ocorrência tem sido descrita para comunidades temperadas ou depauperadas até o presente momento. Para verificar quais fenômenos podem produzir a variação no nicho de lagartos tropicais foi utilizado como modelo Tropidurus hispidus. Os objetivos deste estudo foram: descrever a composição da dieta; investigar a existência de variação intrapopulacional no nicho trófico; determinar em que níveis essa variação se expressa; e testar se a morfologia é um mecanismo subjacente ao uso de recursos alimentares nesta espécie. Dentre os fenômenos analisados, a variação intrapopulacional parece ser ocasionada unicamente pela especialização individual. Os itens mais consumidos por T. hispidus, formigas, besouros e cupins, produzem uma variedade de substâncias químicas tóxicas que podem impor um alto custo para desintoxicação e gerar preferências alimentares individuais. Outra possível fonte de variação é a ocorrência de diferentes comportamentos de forrageio por indivíduos da mesma população. Este é o primeiro registro da ocorrência de especialização individual em lagartos tropicais e reforça a percepção de que esse fenômeno esta presente em comunidades tropicais de alta diversidade, contrariando o padrão estabelecido na literatura, relacionando à ocorrência da especialização individual a comunidades temperadas e depauperadas. / Abstract: The diet is one of the main atributes of the ecological niche of animal species. Generally, the individuals of a population are considered ecologically equivalent in ecological studies that focus on resource use. Nevertheless, this approach has been inadequate to correctly describe resource use by various species, as demonstrated by empirical data. Intrapopulation variation may be caused by exogenous factors or endogenous phenomena such as sexual and/or ontogenetic differences. Additionally, individuals belonging to the same age or sex, and within a single site or time can also show differences in niche. This phenomenon has been defined as "individual specialization" and its occurrence is related to temperate and/or depauperate communities. To verify which phenomena produce niche variation in tropical lizards, we used Tropidurus hispidus as a model system. The aims of this study were to describe the diet composition; to investigate the existence of intrapopulational variation in trophic niche; to determine at which levels this variation is expressed, and test if the morphology is an underlying mechanism in food resource use in this species. The intrapopulation variation seems to be caused uniquely by individual specialization. The most consumed items by T. hispidus, ants, beetles and termites, produce a variety of toxic chemical substances that can impose a high cost for desintoxication and generate individual alimentary preferences. Another possible source of variation is the occurrence of different forage behaviors by individuals of the same population. This is the first record of the occurrence of individual specialization in tropical lizards, which suggests the presence of this phenomenon in highly diverse tropical communities, contradicting the established literature relating the occurrence of individual specialization to temperate and depauperate communities. / Mestrado / Mestre em Ecologia

Body size is a fundamental structural characteristic of organisms, determining critical life history and physiological traits, and influencing population dynamics, community structure, and ecosystem function. For my dissertation, I focused on effects of body size on habitat use and diet of important coastal fish predators, as well as their influence on faunal communities in Bahamian wetlands. First, using acoustic telemetry and stable isotope analysis, I identified high variability in movement patterns and habitat use among individuals within a gray snapper (Lutjanus griseus) and schoolmaster snapper (L. apodus) population. This intrapopulation variation was not explained by body size, but by individual behavior in habitat use. Isotope values differed between individuals that moved further distances and individuals that stayed close to their home sites, suggesting movement differences were related to specific patterns of foraging behavior. Subsequently, while investigating diet of schoolmaster snapper over a two-year period using stomach content and stable isotope analyses, I also found intrapopulation diet variation, mostly explained by differences in size class, individual behavior and temporal variability. I then developed a hypothesis-testing framework examining intrapopulation niche variation between size classes using stable isotopes. This framework can serve as baseline to categorize taxonomic or functional groupings into specific niche shift scenarios, as well as to help elucidate underlying mechanisms causing niche shifts in certain size classes. Finally, I examined the effect of different-sized fish predators on epifaunal community structure in shallow seagrass beds using exclusion experiments at two spatial scales. Overall, I found that predator effects were rather weak, with predator size and spatial scale having no impact on the community. Yet, I also found some evidence of strong interactions on particular common snapper prey. As Bahamian wetlands are increasingly threatened by human activities (e.g., overexploitation, habitat degradation), an enhanced knowledge of the ecology of organisms inhabiting these systems is crucial for developing appropriate conservation and management strategies. My dissertation research contributed to this effort by providing critical information about the resource use of important Bahamian fish predators, as well as their effect on faunal seagrass communities.

The work in this thesis deals with the ecology and evolution of adaptive individual variation. Ecologists have long used niche theory to describe the ecology of a species as a whole, treating conspecific individuals as ecological equivalent. During recent years, research about individual variation in diet and morphology has gained interest in adaptive radiations and ecological speciation. Such variation among individual niche use may have important conservation implications as well as ecological and evolutionary implications. However, up to date we know very little about the extension of this phenomenon in natural populations and the mechanisms behind it. The results in this thesis show that the extension of individual diet specialization is widely spread throughout the animal kingdom. The variation in diet is mainly correlated to morphological variation but not always. Furthermore, this variation in diet and morphology among individuals could be both genetically determined and environmentally induced and it mainly comes from trade-offs in foraging efficiency between different prey types. The results from a number of studies of perch also show that individual perch differ in morphology and diet depending on habitat, where littoral perch has a deeper body compared to pelagic perch. This difference in morphology corresponds to functional expectations and is related to foraging efficiency trade-offs between foraging in the littoral and pelagic zone of a lake. The variation in morphology in perch is mainly due to phenotypic plasticity but there are also small genetic differences between the littoral and pelagic perch. Two separate studies show that both predation and competition may be important mechanism for the variation in morphology and diet in perch. In conclusion, the results in this thesis show that individual variation in diet and habitat choice is a common phenomenon with lots of ecological and evolutionary implications. However, there are many mechanisms involved in this phenomenon on which we are just about to start learning more about, and only further research in this area will give us the full insight.

<p>The work in this thesis deals with the ecology and evolution of adaptive individual variation. Ecologists have long used niche theory to describe the ecology of a species as a whole, treating conspecific individuals as ecological equivalent. During recent years, research about individual variation in diet and morphology has gained interest in adaptive radiations and ecological speciation. Such variation among individual niche use may have important conservation implications as well as ecological and evolutionary implications. However, up to date we know very little about the extension of this phenomenon in natural populations and the mechanisms behind it.</p><p>The results in this thesis show that the extension of individual diet specialization is widely spread throughout the animal kingdom. The variation in diet is mainly correlated to morphological variation but not always. Furthermore, this variation in diet and morphology among individuals could be both genetically determined and environmentally induced and it mainly comes from trade-offs in foraging efficiency between different prey types. </p><p>The results from a number of studies of perch also show that individual perch differ in morphology and diet depending on habitat, where littoral perch has a deeper body compared to pelagic perch. This difference in morphology corresponds to functional expectations and is related to foraging efficiency trade-offs between foraging in the littoral and pelagic zone of a lake. The variation in morphology in perch is mainly due to phenotypic plasticity but there are also small genetic differences between the littoral and pelagic perch. Two separate studies show that both predation and competition may be important mechanism for the variation in morphology and diet in perch.</p><p>In conclusion, the results in this thesis show that individual variation in diet and habitat choice is a common phenomenon with lots of ecological and evolutionary implications. However, there are many mechanisms involved in this phenomenon on which we are just about to start learning more about, and only further research in this area will give us the full insight.</p>