Ecologia alimentar e comportamento de forrageamento de Ameivula aff. ocellifera (Squamata: Teiidae) em área de caatinga do nordeste do Brasil

This study investigated the influence of intrinsic and extrinsic factors on the feeding ecology and foraging behavior of the whiptail lizard Ameivula aff. ocellifera, a new species widely distributed in the Brazilian Caatinga, and that is in process of description. In attendance to the objectives, the Dissertation was structured in two chapters, which correspond to scientific articles, one already published and the other to be submitted for publication. In Chapter 1 were analyzed the general diet composition, the relationship between lizard size and prey size, and the occurrence of sexual and ontogenetic differences in the diet. Chapter 2 contemplates a seasonal analysis of diet composition during two rainy seasons interspersed with a dry season, and the quantitative analysis of foraging behavior during two distinct periods. The diet composition was determined through stomach analysis of lizards (N = 111) collected monthly by active search, between September 2008 and August 2010, in the Estação Ecológica do Seridó (ESEC Seridó), state of Rio Grande do Norte. Foraging behavior was investigated during a rainy and a dry month of 2012 also in ESEC Seridó, by determining percent of time moving (PTM), number of movements per minute (MPM) and prey capture rate by the lizards (N = 28) during foraging. The main prey category in the diet of Ameivula aff. ocellifera was Insect larvae, followed by Orthoptera, Coleoptera and Araneae. Termites (Isoptera) were important only in numeric terms, having negligible volumetric contribution (<2%) and low frequency of occurrence, an uncommon feature among whiptail lizards. Males and females did not differ neither in diet composition nor in foraging behavior. Adults and juveniles ingested similar prey types, but differed in prey size. Maximum and minimum prey sizes were positively correlated with lizard body size, suggesting that in this population individuals experience an ontogenetic change in diet, eating larger prey items while growing, and at the same time excluding smaller ones. The diet showed significant seasonal differences; during the two rainy seasons (2009 and 2010), the predominant prey in diet were Insect larvae, Coleoptera and Orthoptera, while in the dry season the predominant prey were Insect larvae, Hemiptera, Araneae and Orthoptera. The degree of mobility of consumed prey during the rainy seasons was lower, mainly due to a greater consumption of larvae (highly sedentary prey) during these periods. Population niche breadth was higher in the dry season, confirming the theoretical prediction that when food is scarce, the diets tend to be more generalized. Considering the entire sample, Ameivula aff. ocellifera showed 61,0 ± 15,0% PTM, 2,03 ± 0,30 MPM, and captured 0,13 ± 0,14 per minute. Foraging mode was similar to that found for other whiptail lizards regarding PTM, but MPM was relatively superior. Seasonal differences were verified for PTM, which was significantly higher in the rainy season (66,4 ± 12,1) than in the dry season (51,5 ± 15,6). It is possible that this difference represents a behavioral adjustment in response to seasonal variation in the abundance and types of prey available in the environment in each season

Ecologia trófica de uma comunidade de lagartos da caatinga

The trophic ecology studies issues related to the diet of individuals within a community .The relation between the body size of the predator and the prey size, individual specialization and niche breadth are some of the issues that can be discussed by it .I collected the lizards using pitfall trap, glue and active collecting traps in a fragment of Caatinga. The most common species in this community were Tropidurus hispidus, T. semitaeniatus and Cnemidophorus ocellifer. The visits to the farm also relied on collecting invertebrates at each season to understand how the nutritional resources of lizards were presented in each one of them. I tried to answer some questions : 1) If there was a positive relation between body size of the predator and the size of prey of the community ; 2) If in different seasons the relation of body size of the predator and the maximum and/or minimum size of the prey would be positive ; 3) If species with different foraging strategies have positive relation on the size of the predatorprey relation; 4) If the seasonality would influence on the individual expertise of lizards community and more common species; 5) If the breadth of the niche would be influenced by seasonality ; 6) If more individuals with different morphology between them would present less similar diet. I found that there was indeed a positive relationship between size of prey and predator, but nonexistent related to the minimum size of prey; Among the seasons relative size of predators and prey was different for the maximum and minimum size, but was positively related only to the size of the maximum prey. And comparisons between different foraging strategies had the maximum and minimum line inclination greater than zero and different from each other; individual specialization was not influenced by seasonality and the niche breadth was wider in the dry season only to T. semitaeniatus. At last I didn't find a significant negative relationship between morphological dissimilarity and similarity of diet.

Ecologia e história natural de população Hemidactylus agrius (Squamata: Gekkonidae) em área de Caatinga, com avaliação da distribuição das espécies nativas do gênero no nordeste do Brasil

The genus Hemidactylus Oken, 1817 has cosmopolite distribution, with three species occurring in Brazil, two of them native, H. brasilianus and H. agrius, and one exotic, H. mabouia. Considering the studies about ecology of lizards conducted in the Ecological Station of the Seridó, from 2001 to 2011, this study aimed (1) to re-evaluate the occurrence of the species of Hemidactylus in this ESEC; (2) to analyze ecological and biological aspects of the H. agrius population; and (3) to investigate the current and potential distribution of the native species of the genus in northeastern Brazil, analyzing the suitability of ESEC to this taxon. For the first two objectives, a sampling area consisting of five transects of 200 x 20 m, was inspected in alternating daily shifts for three consecutive days, from August 2012 to August 2013. For the latter objective, occurrence points of H. agrius and H. brasilianus from literature and from the database of Herpetological Collections of the UFRN and the UNICAMP were consulted to build predictive maps via the Maximum Entropy algorithm (MaxEnt). In ESEC Seridó, 62 H. agrius individuals were collected (25 females, 18 males and 19 juveniles), and two neonates were obtained from a communal nest incubated in the laboratory. No record was made for the other two species of the genus. Hemidactylus agrius demonstrated to be a nocturnal species specialized in habitats with rocky outcrops; but this species is generalist regarding microhabitat use. In the population studied, females had an average body length greater than males, and showed higher frequencies of caudal autotomy. Regarding diet, H. agrius is a moderately generalist species that consumes arthropods, especially insect larvae, Isoptera and Araneae; and vertebrates, with a case of cannibalism registered in the population. With respect to seasonal differences, only the number of food items ingested differed between seasons. The diet was similar between sexes, but ontogenetic differences were recorded for the total volume and maximum length of the food items. Significant relationships were found between lizard body/head size measurements and the maximum length of prey consumed. Cases of polydactyly and tail bifurcation were recorded in the population, with frequencies of 1.6% and 3.1%, respectively. In relation xv to the occurrence points of the native species, 27 were identified, 14 for H. agrius and 13 for H. brasilianus. The first species presented restricted distribution, while the second showed a wide distribution. In both models generated, the ESEC Seridó area showed medium to high suitability. The results of this study confirm the absence of H. brasilianus and H. mabouia this ESEC, and reveal H. agrius as a dietary opportunist and cannibal species. Further, the results confirm the distribution patterns shown by native species of Hemidactylus, and point ESEC Seridó as an area of probable occurrence for the species of the genus, the establishing of H. brasilianus and H. mabouia are probably limited by biotic factors, a fact yet little understood

Diversidade de cefalópodes e o seu papel no nicho trófico de seus principais predadores nos Arquipélagos de Fernando de Noronha e São Pedro e São Paulo

This study aims, to characterize the diversity of cephalopods by analyzing the stomach contents of fishes caught in the islands of St. Peter and St. Paul (ASPSP) and Fernando de Noronha (AFN). Also, verify the participation of cephalopods in the diet of their main predators. A total of 723 stomachs were collected, from 8 species of fish, caught by the fishery, 471 stomachs were from ASPSP and 252 were from the AFN. It was recorded the occurrence of food items (fish, cephalopods and crustaceans) and the cephalopods were identified to the lowest taxa possible, according to specialized literature. The Ommastrephidae family represented 84.46% of occurrence in the ASPSP and 63.48% in the AFN, confirming the importance of this family in the area studied and also in the diet of their predators. Among the species with greatest occurrence Ornitoteuthis antillarum was the most representative in both regions. This species had an average mantle length of 54.25 mm, thus demonstrating that the majority of this population is in the juvenile stage of development. The smallest species found was Argonauta nodosa with a mantle length of 4.06 mm and the largest was Ommastrephes bartrami, with 223.33 mm. In the AFN, the species richness (d) was 2.318, the diversity index (H ') was 1.454 and the measure of evenness (J) was 0.585. In the ASPSP, the species richness (d) was 2.66, the Shannon diversity index (H ') was 1.013 and the measure of evenness (J) was 0.373. AFN has a greater cephalopod diversity than ASPSP, confirming the pattern suggested by the Theory of Island Biogeography. Among the occurrence of prey items for all predators, the cephalopods are secondary preys. The most important cephalopod species in the diet of Thunnus albacares and Acantocybium solandri was Ornithoteuthis antillarum. These predators have different niche width the diet of Thunnus albacares is more specialized, but they have an overlap of 84.684% in the trophic niche, suggesting that in the ASPSP these two species may use similar niches

Caracterização do nicho alimentar do polvo octopus insularis (cephalopoda: octopodidae): da população ao indivíduo

Octopus insularis, target species in this study, is the dominant benthic octopus of the North and Northeast Brazil. Studies on behavior and ecology of the species have been conducted primarily on oceanic islands, with little information on the continental populations. In this study, two regions of the coast of RN, Rio do Fogo and Pirangi, were chosen for the characterization of the niche by O. insularis populations. The dietary niche, habitat and distribution of O. insularis of oceanic islands and the mainland, were compared. In addition, individual characteristics of feeding behavior in a population at Atol das Rocas was studied, taking into account the size of individuals, the proximity of the dens and characteristics of their "personality". The diet of the Rio do Fogo population was composed mainly of bivalve molluscs (82%), unlike Pirangi population that has a diet consisting mainly of crustaceans Decapoda (68%), similar to that described for the populations of the islands. Consequently, the feeding niches of the island populations were more similar, with greater overlap, but the niche breadth of the continent was larger. The habitats of occurrence on the coast includes reefs, rocks, gravel and an environment called Restinga, a plateau composed of biogenic gravel, sand, sponges and algae, showed a high density of animals. Similarly to that found in the islands, O. insularis in the continent, had a clumped distribution, and a bathymetric segregation between small and large individuals. The differences in diet composition among populations were explained by differences in habitat and coverage of the substrate, which may be directly influencing the diversity and prey availability in these environments. The individual analyzes of the population at Atol das Rocas, showed no relationship between the degree of individual specialization and the different personalities, or the distance between dens. The results suggest that the foraging strategy with greater availability of prey in the environment has an influence on diet octopuses over preferences or personalities

Aspectos da ecologia trófica de duas espécies simpátricas de Aegla (Crustacea, Anomura)

Os crustáceos decápodos da família Aeglidae são os únicos anomuros que ocorrem em águas continentais, na região subtropical e temperada da América do Sul. Entre as mais de 60 espécies descritas, várias são simpátricas, destacando-se Aegla camargoi Buckup & Rossi, 1977 e Aegla leptodactyla Buckup & Rossi, 1977, que ocorrem no Rio da Divisa, Município de São José dos Ausentes, RS Com o objetivo de obter informações sobre a ecologia trófica das espécies, com ênfase na partição de nicho trófico, os animais foram coletados sazonalmente, em intervalos de 6 horas, por 24 horas. Em laboratório, foi analisado o conteúdo estomacal, utilizando as técnicas de método dos pontos, classificação do grau de repleção estomacal, freqüência de ocorrência, e índice alimentar. A análise indicou que os animais são omnívoros, alimentando-se preferencialmente de macrófitas, insetos imaturos das ordens Ephemeroptera, Trichoptera, Coleoptera e Diptera. Aegla leptodactyla mostrou maior preferência por macrófitas, relacionada a sua predominância nos ambientes onde ocorrem em maior abundância. A estimativa de repleção estomacal indicou que as duas espécies alimentam-se em todos os horários. Foram identificados e descritos os principais ossículos e estruturas que compõem o estômago desses crustáceos. Não foram detectadas diferenças na morfologia dos estômagos cardíaco e pilórico das espécies. Ambas possuem estômagos desenvolvidos, com dentes robustos, característicos de animais macrófagos. As peças bucais de ambas espécies, como as mandíbulas, maxilas e maxilípodos foram descritas e comparadas, diferindo apenas em relação ao número de dentes da crista dentata do terceiro maxilípodo. A mandíbula é bem desenvolvida, característica de caranguejos predadores. A largura do nicho trófico de cada espécie foi estimada, mostrando pequenas variações sazonais. A sobreposição de nicho trófico entre as duas espécies ocorre em todas as estações, corroborando os resultados obtidos da análise do conteúdo estomacal. Concluiu-se que as espécies são omnívoras generalistas, partilhando os recursos disponíveis no ambiente.

Estrutura da população de Coleodactylus natalensis Freire, 1999 (Squamata: Sphaerodactylidae) no Parque Estadual Dunas de Natal, Rio Grande do Norte, Brasil

Coleodactylus natalensis Freire, 1999, an endemic species of Atlantic Forest fragments around the Natal municipality, Rio Grande do Norte State, Brazil, has as type locality the Parque Estadual Dunas de Natal (05º48 S to 05º53 S and 35º09 W to 35º12 W), one of the largest restinga (herb and shrub association on sand dunes along the Brazilian coastline) associate fragment, surrounded by urban zone, placed on setentrional Atlantic Forest limits. We made estimates on populational density, spatial distribution, habitat and microhabitat preferences and feeding ecological aspects like sazonal and sexual variations on diet, prey electivities and niche breadth. We randomly sampled ninety-six 50m2 quadrants in each of the four habitats identified in the study area. Were collected 49 specimens and their stomach contents were analyzed; prey items found were correlated with leaf-litter invertebrates from habitat samples. We found a 98,5 ± 75,5 individuals/ha density, in grouped distribution pattern on densest habitats and random distribution on others habitats. This species lives mostly on leaf-litter in forest habitats, in higher humidity points, with lower temperatures, deeper leaf litter and lower sea level elevations than the randomly chosen points in the study area. Isopoda and Aranae were the most important prey categories in numeric, frequency and volumetric terms. Niche breadth has an intermediate value and was variable in sexual and in habitat terms. There was no correlation between morfometric measures and prey size on diet. The C. natalensis population studied seems to be diet opportunist, although selects larger prey items. The Parque Estadual das Dunas do Natal has several indications of anthropic pressure from the surrounding urban area that may affects the local C. natalensis population. Thus, the fragility of this species calls for urgent conservation efforts

Ecologia trófica de anfíbios anuros: relações filogenéticas em diferentes escalas

Understand the origin, maintenance and the mechanisms that operate in the current biodiversity is the major goal of ecology. Species ecology can be influenced by different factors at different scales. There are three approaches about the ecological differences between species: the first brings that differences result from current processes on niche characteristics (e.g. diet, time, space); the second that species differences are explained by random patterns of speciation, extinction and dispersion, the third that historical events explain the formation and composition of species in communities. This study aims to evaluate the influence of phylogenetic relationships in determining ecological characteristics in amphibians (globally) and test with that, if ecological differences between species of frogs are the result of ancient pre-existing differences or as result of current interactions. Another objective of this study is to verify if ecological, historical or current characteristics determine the size of species geographical distribution. The diet data for analysis of trophic ecology were collected from published literature. We performed a non-parametric MANOVA to test the existence of phylogenetic effects in diet shifts on frogs history. Thus, it is expected to know the main factors that allow the coexistence of anuran species. We performed a phylogenetic regression to analyze if niche breadth, body size and evolutionary age variables determine the size of the geographical distribution of amphibians in the Amazon. In the present study, new contributions to knowledge of major ecological patterns of anurans are discussed under a phylogenetic perspective

Patterns of spatial distribution in macroalgal communities from tropical lotic ecosystems

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

A importância de fragmentos florestais na diversidade de anfíbios anuros em Icém, Região Noroeste do Estado de São Paulo

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Estrutura da população de Coleodactylus natalensis Freire, 1999 (Squamata: Sphaerodactylidae) no Parque Estadual Dunas de Natal, Rio Grande do Norte, Brasil

Coleodactylus natalensis Freire, 1999, an endemic species of Atlantic Forest fragments around the Natal municipality, Rio Grande do Norte State, Brazil, has as type locality the Parque Estadual Dunas de Natal (05º48 S to 05º53 S and 35º09 W to 35º12 W), one of the largest restinga (herb and shrub association on sand dunes along the Brazilian coastline) associate fragment, surrounded by urban zone, placed on setentrional Atlantic Forest limits. We made estimates on populational density, spatial distribution, habitat and microhabitat preferences and feeding ecological aspects like sazonal and sexual variations on diet, prey electivities and niche breadth. We randomly sampled ninety-six 50m2 quadrants in each of the four habitats identified in the study area. Were collected 49 specimens and their stomach contents were analyzed; prey items found were correlated with leaf-litter invertebrates from habitat samples. We found a 98,5 ± 75,5 individuals/ha density, in grouped distribution pattern on densest habitats and random distribution on others habitats. This species lives mostly on leaf-litter in forest habitats, in higher humidity points, with lower temperatures, deeper leaf litter and lower sea level elevations than the randomly chosen points in the study area. Isopoda and Aranae were the most important prey categories in numeric, frequency and volumetric terms. Niche breadth has an intermediate value and was variable in sexual and in habitat terms. There was no correlation between morfometric measures and prey size on diet. The C. natalensis population studied seems to be diet opportunist, although selects larger prey items. The Parque Estadual das Dunas do Natal has several indications of anthropic pressure from the surrounding urban area that may affects the local C. natalensis population. Thus, the fragility of this species calls for urgent conservation efforts

Diversidade de espécies e ecologia da comunidade de lagartos de um fragmento de Mata Atlântica no nordeste do Brasil

Neste estudo foram investigadas a diversidade, a composição, e as diferenças no uso do espaço (hábitat e microhábitat) e do alimento em uma comunidade de lagartos habitantes da serapilheira de um fragmento de Mata Atlântica, do Estado de Alagoas, Brasil. Para a observação e/ou coleta dos espécimes, foram utilizados os métodos de busca ativa e armadilhas de queda (pit-fall traps) sem cerca-guia. Para análises de diversidade e da existência de diferenças de diversidade entre os hábitats e microhábitats, utilizou-se o índice de Shannon. A largura dos nichos espacial (hábitat e microhábitat) e alimentar foi avaliada, utilizando-se o índice de diversidade de Simpson. A similaridade entre as áreas foi averiguada utilizando-se o índice de Jaccard. Para avaliar o grau de sobreposição quanto ao uso do espaço (hábitats e microhábitats) e do alimento pelas espécies, foi utilizada uma versão da equação de MarcArthur & Levis. Foram obtidas vinte e três espécies de lagartos, pertencentes a nove famílias; destas, dezenove foram obtidas no interior da mata e nove na borda. Para o interior da mata as espécies mais abundantes foram Kentropyx calcarata, Dryadosaura nordestina, Enyalius catenatus e Gymnodactylus darwinii. Na borda da mata as espécies mais abundantes foram Tropidurus hispidus, T. semitaeniatus, Ophiodes striatus e Ameiva ameiva. Quanto à utilização dos recursos, os resultados mostraram que espécies filogeneticamente próximas nem sempre utilizam de maneira semelhante os recursos disponíveis. A dieta em geral foi composta por artrópodes. Tropidurus hispidus e T. semitaeniatus se mostraram especialistas no consumo de Himenoptera (Formicidae), que estiverem presentes em 100% dos seus estômagos. Ophiodes striatus teve como principal alimento caramujos (Gastropoda) e aranhas com 60% cada; sendo Gastropoda mais abundante para esta espécie

Efeito da irrigação e da ontogenia sobre a estimativa da área foliar de Hancornia speciosa Gómez (mangabeira)

A estimativa da área foliar por meio de curvas de regressão que empregam o produto do comprimento pela largura do limbo como variável independente, é uma prática comumente empregada na análise de crescimento vegetal. Entretanto, dependendo da natureza do material vegetal e das condições de cultivo, é possível a ocorrência de variações que afetam essa relação alométrica, o que implica a não universalidade de uma única curva de regressão. Devido a esse problema, o presente trabalho teve como objetivo realizar uma avaliação do efeito da irrigação e da ontogenia sobre a estimativa da área foliar da Hancornia speciosa, para testar a hipótese de que a irrigação afetaria tal relação alométrica. Verificou-se que os modelos de regressão obtidos para as plantas irrigadas e para as não irrigadas diferiram entre si, sendo que houve a necessidade da inclusão da área foliar específica no modelo de estimativa da área foliar das plantas não irrigadas. A não inclusão dessa variável no modelo de regressão acarretou uma diferença de estimativa que se incrementou com a redução da área foliar específica. Em folhas recém-expandidas de plantas irrigadas e não irrigadas, verificou-se diferença na área foliar específica devida à alteração na massa seca e não associada à largura dos tecidos foliares.

A diversidade de lagartos na Caatinga é mediada pelos térmitas?

Intending to explain the extraordinary lizard coexistence levels found in Australian deserts, Morton & James (1988) figured out a hypothesis which defends that the termite diversity would bring about lizard radiation. This study aims to verify the validation of that hypothesis in Caatinga lizard assemblages. This study also objectives verifying if the termite defense mechanisms influence their consuming levels by lizards and if this pattern differs between different lizard lineages. Termites were collected using a standardized sampling protocol of termites. Besides using haphazard sampling, we collect lizards with 108 pitfall traps in each area. Intending to check the linkage between the termite and lizard assemblages, the lizard stomach contents were analyzed and then a canonical correspondence analysis was performed. The presence of nonrandom patterns of diet overlap among the lizard species was also examined. Aiming to check if the defense mechanisms of termite influence their consuming pattern by lizards it was performed a laboratory experiment where termite with different defense mechanisms were offered to lizards of two different lineages. We verified that lizard assemblages do not consume termites according to termite abundance in ecosystems. Furthermore, mean niche overlap lizard species did not differ significantly from that expected by chance. We found that termite chemical defense mechanism does influence the termite s pattern consuming by lizards. These results do not corroborate premises which support Morton & James hypothesis (1988) and point out that lizard do not chose termites based on their abundance, but, trying to avoid consuming termites which exhibit chemical defense mechanisms. This defense mechanism, however, may not be the only explanation to patterns of termite s consuming by lizards.

Estrutura da Comunidade de Lagartos de um remanescente de mata atlântica do Estado do Rio Grande Do Norte, Brasil.

As part of a broader project, Diversity and Distribution Patterns of Floristic and Faunistic composition of remnants of Potiguar s Atlantic Forest, as subsidies to conservation , that subsidizes a group of institutional research, This study aimed to evaluate the structure of the assemblage of lizards a remnant of the of the northern Atlantic Forest, identifying ecological factor (s) that contribute to the coexistence of sympatric species. Additionally, we studied the thermal ecology and thermoregulatory behavior of umbrophily and heliophily species live the Parque Estadual Mata da Pipa (PEMP), a remnant of Atlantic forest located in the Tibau do Sul municipality of, Rio Grande do Norte State, Brazil. It is one of the largest remnants of the Atlantic Forest and has an area of approximately 290 ha. The study was performed by four excursions to the field for 20 days each, when active search and pitfalls traps were used to record and colleted specimens in different habitats of the area. We recorded the presence of 19 species of lizards, of which seven are typical of forest areas, three are endemic Atlantic Forest, these two northern and one are new record for the Rio Grande do Norte. The use of resources, the results showed that phylogenetically related species do not always use a similar way the resources available; the feeding niche was the segregated component of the species that overlapped extensively in the use of space and vice versa. To examine the thermal ecology and thermoregulatory behavior of Kentropyx calcarata and Coleodactylus natalensis, we recorded the clocal temperature (Tc), oh the substrate (Ts) and of the air (Ta) to investigate what of these are the source of heat more important to the temperature s body of these lizards. Behavioral observations were conducted to analyze strategies to optimize the acquisition of heat. The air temperature explained most strongly to variation in body temperature of K. calcarata, while the temperature of the substrate to C. natalensis. As for the behavioral observations, they confirmed that K. calcarata is an active thermoregulatory; C. natalensis is a passive thermoregulatory.