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The knowledge about natural history of a species is fundamental for the proposition of theories in population, community, and behavioral ecology. Dermatonotus muelleri (Boettger, 1885) is one of the several Neotropical anuran species that still lacks basic information. These frogs are widely distributed in South America and present many peculiar morphological features, such as a reduced head size and a tongue morphology that suggests a specialized diet in ants and termites. However, D. muelleri is rare in anuran surveys, because of the explosive breeding behavior, which restrict its occurrence in aquatic habitats to few days a year, and the semi-fossorial habit, making the individuals inactive during most part of the year. In this study, we describe the reproductive ecology of Dermatonotus muelleri, with special attention to the mechanisms that regulates (i) the reproductive synchrony between males and females and (ii) the operational sex ratio (OSR), and (iii) if size is a good predictor of pairs formation (assortative mating).

Many factors influence the structure of natural assemblages. Species interaction and environmental factors may generate deterministic patterns, whereas dispersal and ecological drift may generate stochastic patterns. We used pond systems to understand how deterministic and stochastic factors interact and influence tadpole assemblages at different spatial scales. We used variation partitioning and a co-occurrence analysis to evaluate how local environment heterogeneity, species interaction, and spatial variables affected species composition at local and regional scales in Brazilian savanna. Both deterministic and stochastic processes were important to explain tadpole distribution at regional scale, but with a greater contribution of stochastic factors. At local scales, environmental and niche traits were more important to explain tadpole distribution into the habitats. We demonstrate that in Brazilian Cerrado, species composition can be explained by the "MacArthur paradox", in which niche processes are important at local scales, whereas dispersal constraints and population processes lead to stochastic patterns in species distribution at large spatial scales.

Predator–prey interactions can cross ecosystem boundaries and the outcome of these interactions is seen in prey defensive behavior. We aimed to test how the presence of a semi-aquatic predator alters the behavior and foraging microhabitat of Dendropsophus minutus tadpoles when they are either in groups or alone. We hypothesized that in the presence of a predator, Thaumasia fishing spider, tadpoles will be (1) less active; (2) forage far from the predator and; (3) forage evenly when in groups. We measured activity and foraging microhabitat as the proportion of time spent moving, and the total percentage of food removed from the upper and lower inner surfaces of the aquarium, respectively. The presence of the spider reduced tadpole activity by 24% compared to treatments without predators. Contrary to our expectations, solitary tadpoles were 34% more active than tadpoles in groups, and larger larvae were less active than smaller ones. The presence of the fishing spider decreased tadpoles activity, but the presence of conspecifics did not dilute the predator effect. Larger larvae are under more substantial selective pressure than smaller ones. Finally, our experiment empirically demonstrates that predator effects are transferable, generating a cascading system, and affecting the recipient ecosystem in various manners.

Despite the common poison and mucous glands, some amphibian groups have differentiated glands associated with reproduction and usually present on the male ventral surface. Known as breeding glands or sexually dimorphic skin glands (SDSGs), they are related to intraspecific chemical communication during mating. Until recently, reproduction associated with skin glands was recognized only in salamanders and caecilians and remained unexplored among anurans. The Brazilian microhylid

Tadpoles are abundant in the environments in which they occur and remain in aquatic habitats for longer periods than adults, being relatively easier to collect. Despite the increase in tadpole research in the past decade, our understanding of its morphological diversity remains limited. Here, we provide morphological characterizations for larvae of 15 anuran species that occur at Emas National Park (ENP) and its surroundings, in Goiás, and compare them with descriptions available in the literature for other locations. We also present an update of the list of anuran species known to the ENP, based on tadpole sampling. We found tadpoles from 15 anuran species, of which five represent new records for the park. Many species showed variations in morphological characters when compared with descriptions available in the literature for other locations, reinforcing the importance of describing larvae from different populations. Through the exploration of morphological characters, it is possible to make inferences about the functional diversity of the larvae and questions related to the homology of characters, in addition to assisting in the identification and taxonomic distinction of species. Studies with tadpole communities can generate key information about the factors that drive the anurans' richness and distribution and can provide support for establishing more consistent conservation strategies and management plans. Resumo: Os girinos são abundantes nos ambientes que ocorrem e permanecem nos habitats aquáticos por períodos de tempo mais longos que os adultos, sendo relativamente mais fáceis de coletar. Apesar do aumento da pesquisa com girinos na última década, nossa compreensão sobre sua diversidade morfológica ainda permanece limitada. Aqui, fornecemos caracterizações morfológicas para larvas de 15 espécies de anuros que ocorrem no Parque Nacional das Emas (PNE), Goiás, e comparamos com descrições disponíveis na literatura para outras localidades. Apresentamos também uma atualização da lista de espécies de anuros conhecidos para o PNE, com base na amostragem de girinos. Encontramos larvas de 15 espécies de anuros, das quais cinco representam novos registros para o parque. Muitas espécies apresentaram variações nos caracteres morfológicos quando comparamos com descrições disponíveis na literatura para outras localidades, reforçando a importância da descrição de larvas de diferentes populações. Através da exploração de caracteres morfológicos é possível realizar inferências sobre a diversidade funcional das larvas e questões relativas à homologia de caracteres, além de auxiliar na identificação e distinção taxonômica das espécies. Estudos com comunidades de girinos podem gerar informações importantes sobre os fatores que impulsionam a riqueza e a distribuição dos anuros e, podem fornecer suporte para o estabelecimento de estratégias de conservação e planos de manejo mais consistentes.

Made available in DSpace on 2020-12-12T02:29:58Z (GMT). No. of bitstreams: 0 Previous issue date: 2020-03-01 Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) For grazing animals that share spatial and alimentary resources, the relationship between differences in oral morphology and the physical properties of substrates can help explain how and where species forage. The substrates may require different efforts from animals to access and remove food from their surfaces. Variation in oral morphology may produce differences in animals’ feeding efficiency. We tested whether one substrate characteristic, the surface texture (i.e., smooth, striated and rough), influences the growth and food consumption rates of anuran larvae from nine species with different oral morphologies. Tadpoles with few keratinized oral structures and those with more gaps in the marginal papillae row were more efficient grazing on smooth and rough surfaces, respectively. This may indicate possible feeding specializations. Conversely, tadpoles with a high number of labial tooth rows, regardless of the number of gaps in these structures, and those with only a dorsal gap in the marginal papillae row were equally efficient feeding upon all substrate textures. Tadpoles with the generalized labial tooth row formula 2(2)/3(1), had higher growth rates than the other species, suggesting an adaptive significance for this common oral morphology. We demonstrated that species differ in feeding efficiency when grazing on substrates with different textures. This can help elucidate the adaptive significance of variation in tadpole oral morphology. We also provide insights on resource selection and niche partitioning among species, especially for those whose diets do not differ in quantity or quality, as it is common in anuran larval assemblages. Departamento de Ecologia UFG-Universidade Federal de Goiás Departamento de Zoologia E Botânica UNESP-Universidade Estadual Paulista “Júlio de Mesquita Filho” Department of Biology Allegheny College Department of Cellular and Physiological Sciences University of British Columbia Departamento de Zoologia E Botânica UNESP-Universidade Estadual Paulista “Júlio de Mesquita Filho” CAPES: 1562647 FAPESP: 2010/52321-7 CNPq: 302328/2017-3 CNPq: 420051/2016-3 CNPq: 563075/2010-4

Understanding how community compositions are affected by environmental and spatial factors are essential to provide knowledge about the distributions of species. Furthermore, these factors can play a role in species morphological variation. Tadpoles can be found in different types of aquatic microhabitats, showing a considerable amount of morphological diversity. We hypothesized that tadpole morphological diversity is controlled by ecological and spatial factors other than assemblage attributes, and that tadpole assemblage composition is affected by spatial factors. To test these hypotheses, we recorded the abundance of tadpoles from different ponds, identified eight environmental variables that represented local and landscape descriptors of the ponds, recorded the spatial coordinates of the ponds, and measured the morphological variation of assemblages. Spatial factors significantly affected the composition of tadpole assemblages, while both spatial and environmental factors affected morphological variation. The ability of tadpoles to alter their morphology in response to environmental factors might be a result of poor oviposition site choice, and this probably interacts with spatial factors to control the assemblage composition of tadpoles. Morphological variation is advantageous for tadpoles because it allows them to adjust their morphology to environmental conditions. This study has demonstrated how factors that control the assemblage composition of tadpoles also drive their morphological diversity.

The herbicide glyphosate is widely used on Brazilian crops and commonly found in water bodies. Despite its usefulness in controlling pests and increasing agricultural production, improper use of this environmental contaminant might accelerate the decline of species, especially frogs. The aim of this study was to evaluate the genotoxic and mutagenic effects of glyphosate Roundup Original® in tadpoles of Dendropsophus minutus by comet assay and micronucleus test. Fourteen egg masses were collected in two permanent ponds in Chapada dos Veadeiros National Park in Alto Paraiso de Goias, Brazil. Acute exposure was conducted with 180 tadpoles maintained for 99 d in a storage tank until developmental stages 26–31. During acclimation, tadpoles were distributed among 36 tanks and exposed to the following concentrations of the active ingredient (ai) glyphosate Roundup Original®: 0.28 mg ai/L, 1.0 mg ai/L, 2.0 mg ai/L, 4.0 mg ai/L of, negative control (0 mg ai/L), and positive control (10 mg ai/L mitomycin C). After 96 h of exposure, the tadpoles were euthanized with 5% benzocaine and submitted to comet assay and micronucleus test. In the comet assay, a significant increase in DNA damage was observed in response to the 0.28 mg ai/L concentration for tail length, % DNA in the tail, and Olive tail moment. There was no dose-response effect at other concentrations. For the micronucleus test, we did not find a statistically significant increase in micronuclei in erythrocytes of D. minutus after 96 h of exposure to glyphosate. Therefore, in the present study we found that tadpoles of D. minutus are extremely sensitive to low concentrations of glyphosate, demonstrating the importance of amphibian tadpoles in studies of genotoxicity and mutagenicity.

We present a description of the external morphology of Phyllomedusa azurea and describe the internal oral morphology of P. azurea and P. oreades from populations of the Brazilian Cerrado. We also present a comparison with the available descriptions of the external morphology of tadpoles from the P. hypochondrialis group and review the internal oral morphology of the Phyllomedusa genus. The tadpole of P. azurea is characterized by a tooth row formula of 2(2)/3(1), few submarginal papillae, and spiracle positioned ventrally. Phyllomedusa oreades has a diamond-shaped buccal floor, numerous pustulations randomly distributed throughout the buccal floor arena, and a triangular buccal roof. The variation observed in the morphology of P. azurea tadpoles highlights the need to understand how morphological variation affects traits used in species diagnosis and the extent to which this variation could be explained by resource use, geographic variation, and/or ontogeny.

Agriculture and pasture activities are the main drivers for habitat reduction, directly affecting amphibian assemblages. In the Cerrado, the progress of agricultural and pasture areas negatively affects aquatic environments and their organisms, once the suppression of marginal vegetation reduces the natural protection against allochtone stressors. One possible way to measure the stress level is the Fluctuating Asymmetry (FA), which is calculated based on the deviations in the development of bilateral morphological traits of the organism. Herein, we evaluated whether environments with a higher degree of agropastoral influence and reduced marginal vegetation can increase FA levels in tadpoles of two common and widely distributed anuran species in the Cerrado (Physalaemus cuvieri and Scinax fuscomarginatus). We sampled and classified water bodies according to the percentage of agropastoral land use and marginal vegetation, and measured four morphological traits of tadpoles to evaluate the degree of FA. We found that in environments with intensive agropastoral land use, tadpoles of P. cuvieri and S. fuscomarginatus had higher FA in nostril-snout distance (NSD). In environments with reduced marginal vegetation, tadpoles of S. fuscomarginatus had higher FA in eye width (EW), but no effect was detected for tadpoles of P. cuvieri. These morphological traits (i.e. nostrils and eyes) are associated to individual fitness of tadpoles. Thus, these developmental deviations can affect species fitness and population homeostasis over time, contributing to generate stochastic population dynamics and increasing the vulnerability of native species to local extinctions. The use of FA as a tool to measure environmental impact on species with potential to be used as bioindicators can contribute to generate and test hypothesis when integrated with long-term studies.

Amphibians are constantly exposed to pollutants and the stress of agricultural activities. We selected three anuran amphibian species Dendropsophus minutus, Boana albopunctata, and Physalaemus cuvieri, totaling 309 individuals. We collected tadpoles in 15 permanent ponds: 5 soybean crops, 3 corn crops, and 7 nonagricultural lands. Our study provides the first comparative data on the genotoxicity and mutagenicity of three common amphibian anurans. Dendropsophus minutus was the most vulnerable species compared with B. albopunctata and P. cuvieri for comet assay and micronuclei test. However, the more significant amount of DNA damage seen in D. minutus does not mean that their populations are threatened once such species adapt well to anthropogenic disturbances. Despite, P. cuvieri was less sensitive than the other two species; the DNA damage was significantly higher in soybean crops. Physalaemus cuvieri is a leptodactylidae species that deposit their eggs in foam nests, which are essential to protect eggs from dehydration. Moreover, the foam reduces the contact of eggs with water; thus, P. cuvieri eggs could be less exposed to contaminants present in pounds, compared with D. minutus and B. albopunctata, which deposit their eggs directly in the water. Therefore, this study was sufficiently sensitive to detect genotoxic and mutagenic effects in tadpoles exposed to agroecosystems. We strongly suggest D. minutus in future biomonitoring studies that involve the comparison of anthropized versus not anthropized environments. Overall, we recommend the comet assay and micronucleus test as effective methods for the detection of genotoxic damage in amphibian anurans to the environmental disturbance, especially in agricultural sites.

No ambiente natural, os animais são expostos a uma grande quantidade de ameaças a sobrevivência. Considerar a ecologia do medo é importante para estimar o papel ecossistêmico que os predadores desempenham nas comunidades, uma vez que o medo de um predador pode provocar não somente respostas baseadas em densidade (i.e., remoção de indivíduos de uma população), como também respostas comportamentais, que podem resultar em efeitos em cascata. Comportamentos defensivos são relativamente simples de serem avaliados em situação de cativeiro, uma vez que são conspícuos e específicos, dificilmente sendo confundidos com outros comportamentos quando observados. Desta forma, o objetivo deste estudo foi verificar a habilidade de indivíduos de Tamandua tetradactyla (Linnaeus, 1758) em detectar pistas indiretas de um predador, para avaliação de risco do ambiente. Neste estudo, seis indivíduos de tamanduás-mirim (T. tetradactyla) em cativeiro foram expostos a pistas indiretas (e.g., urina e fezes) de jaguatirica (Leopardus pardalis). No total, cinco machos e uma fêmea de tamanduá foram observados pelo método de animal focal, em um esforço total de 36 horas de observação. Tamanduás-mirins alocados nos recintos com pistas indiretas do predador exibiram maior frequência de comportamentos anti-predatórios e diminuição dos comportamentos de inatividade. A utilização de pistas indiretas é vantajosa para indivíduos de tamanduá-mirim, pois permitem a avaliação de risco de uma determinada mancha do ambiente e elicia comportamentos de evitação, que são menos custosos energeticamente. A porcentagem de comportamentos também é apresentada com e sem as pistas indiretas do predador de T. tetradactyla, na qual pode ser útil para entender a capacidade de resposta de tamanduás-mirins a situações de perigo.Palavras chave: Ecologia do medo, tamanduá-mirim, jaguatirica, comportamentos anti-predatórios.

Bokermannohyla (tribe Cophomantini) is an endemic genus of Brazilian treefrogs containing 32 species arranged into four phenetic groups. The B. pseudopseudis group includes nine species, which are typically found in rupestrian ecosystems of disjunct Brazilian mountain ranges. Tadpoles have been shown to be important sources of information for the taxonomy of this genus, although careful analyses of character variation and descriptions of internal anatomy remain scarce. Since the first description of B. pseudopseudis tadpoles was based on a mixed series containing specimens of B. pseudopseudis and B. sapiranga, we describe the larvae of these two species from their type localities, including their external morphology, oral cavity, and skeletal system. Tadpoles of B. pseudopseudis are easily distinguished from those of B. sapiranga by aspects of their coloration and characters of their oral disc (more labial tooth rows, more numerous submarginal papillae and flaps with labial teeth). These morphological differences may be diagnostic for these two similar species, whereas their chondrocranium, hyobranchial apparatus, and oral cavity are alike, suggesting less variability in these character systems between closely related species. Finally, we provide the first comparison of data on the skeletal system of Bokermannohyla and other Cophomantini, highlighting characters of potential relevance to the systematics of the tribe.

In nature, tadpoles encounter food on substrates oriented at different angles (e.g. vertically along stems, horizontally on the bottom of the pond). We manipulated the orientation of food-covered surfaces to test how different orientations of surfaces affect tadpoles' feeding efficiency. We studied taxa that differed in the oral morphology of their larvae and position in the water column. We hypothesized that species would differ in their ability to graze upon surfaces at different orientations and that differences in the tadpoles' feeding ability would result in different growth rates. The orientation of food-covered surfaces did not affect the growth rate of bottom-dwelling tadpoles (whose growth rate varied only between species). Among midwater tadpoles, some species appear to have a generalist strategy and experienced a high relative growth rate on numerous substrate orientations, whereas others achieved high growth rates only on flat substrates (i.e. at 0° and 180°). We conclude that oral morphology constrains tadpoles' ability to feed at different substrate orientations, and this could lead to niche partitioning in structurally complex aquatic environments. Because physical parameters of the environment can affect tadpoles' growth rate, characterizing these features might help us better understand how competition structures tadpole assemblages., Summary: We provide new insights on species' niche partitioning as we show that the orientation of substrates can affect the growth rates of tadpoles with different oral morphologies.

Amphibian larvae are highly susceptible to contamination, which can lead to lethal and sublethal effects. This impact can be measured by fluctuating asymmetry (FA), which is based on differences between the sides of organisms with bilateral symmetry. We evaluated the effect of acute and chronic exposure to Roundup Original ® on Physalaemus cuvieri tadpoles. We measured tadpole survival and estimated the LC5096h. We also evaluated whether a sublethal concentration increases the FA. In acute exposure, survival was reduced and the LC50 was 2.13 mg a.i./l. In chronic exposure, nostril–snout distance and eye width had a significantly higher FA in contaminated tadpoles. The chronic exposure to contaminants could lead to several sublethal effects, which would be used in biomonitoring surveys. Morphological traits affected by contaminants, such as malformations or FA, would be relatively more easily measured from field samples. Because it is cost effective, easy to measure, and can be obtained without tagging or housing field-caught animals, we suggest that FA is a promising marker for monitoring the environmental impacts of contaminants like Roundup. However, additional studies are necessary to understand what additional environmental stressors might impact FA, and how this might alter its utility for use in biomonitoring.

Temperature impacts ectotherm performance by influencing many biochemical and physiological processes. When well adapted to their environment, ectotherms should perform most efficiently at the temperatures they most commonly encounter. In the present study, we tested how differences in temperature affects the feeding kinematics of tadpoles of two anuran species: the benthic tadpole of Rhinella schneideri and the nektonic tadpole of Trachycephalus typhonius. Benthic and nektonic tadpoles have segregated distributions within ponds and thus tend to face different environmental conditions, such as temperature. Muscle contractile dynamics, and thus whole organism performance, is primarily temperature dependent for ectotherms. We hypothesized that changes in mean temperatures would have differential effects on the feeding kinematics of these two species. We conducted a laboratory experiment in which we used high-speed videography to record tadpoles foraging at cold and warm temperatures. In general, tadpoles filmed at warm temperatures opened their jaws faster, attained maximum gape earlier, and exhibited shorter gape cycles than tadpoles in cold temperatures, irrespective of species. We also found species x temperature interactions regarding the closing phase velocity, and the percentage of time it takes tadpoles to achieve maximum gape and to start closing their jaws. These interactions could indicate that these two co-occurring species differ in their sensitivity to differences in water temperature and have temperature-dependent feeding strategies that maximize feeding performance in their preferred environment.

Tadpoles have diverse morphologies and occupy diverse habitats. The morphological differences between tadpoles can be represented by linear and geometric measurements and used to explain the organization of tadpole assemblages. However, the effects of evolutionary history must be isolated from the morphological differences before we can determine which patterns result from the use and sharing of common ecological resources. Here, we aimed to determine how morphological similarities and phylogenetic distances affect microhabitat choice by tadpoles. We analyzed the tadpoles of 101 anuran species and classified them according to ecomorphological guild, habitat use, position in the water column, and floor substrate. We used geometric and traditional morphometric approaches to describe the morphological variation among tadpoles and calculated the patristic distance for each species. Afterwards, we used morphometric and phylogenetic matrices as predictors of the variance in the ecological matrix, using a partial redundancy analysis. When we used traditional morphometric data, phylogeny explained a large amount of the ecological variation. By contrast, when we used geometric morphometric data, morphology and phylogeny explained similar amounts of the ecological variation, showing that the technique used to extract morphological variation affects the results. We provide evidence that both morphology, as a surrogate for contemporary factors, and evolutionary inertia are important in determining the behavior of tadpoles. Thus, niche conservatism can be important in modeling the behavior of tadpoles, but does not explain all the preferences of tadpoles.

Made available in DSpace on 2018-11-26T17:42:20Z (GMT). No. of bitstreams: 0 Previous issue date: 2017-10-01 Fundacao de Amparo a Pesquisa (FU-NAPE) Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq) Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) Instituto Chico Mendes de Conservacao da Biodiversidade/Centro Nacional de Pesquisa e Conservacao de Repteis e Anfibios (ICMBio/RAN) Our study determines the reptile species richness, composition, and habitat use in three areas recovering from mining activity in addition to the adjacent pristine and anthropized areas of a priority region for biodiversity conservation of the Brazilian Cerrado. We also compared our data with published surveys on the Cerrado domain in order to identify areas with unique species composition and/or areas where the reptile composition is more homogeneous. The survey was conducted in the municipality of Niquelandia, northern Goias state, central Brazil, and involved reptile samplings from different physiognomies and water bodies. We found 47 species, including one crocodilian, one chelonian, two amphisbaenians, 17 lizards, and 26 snakes. The list includes 37 species with large geographic distribution, occurring in other morphoclimatic domains, as well as 10 species which are endemic to the Cerrado. Some species recorded for the region are listed in the Appendices I and II of the CITES. Many reptile species were frequently associated with anthropogenic habitats, while others seem to depend on remnants of pristine habitats. Low similarity was found among the 32 sites considered across the Cerrado domain. Ten sites located in Cerrado regions in contact with the adjacent domains have unique reptile composition, whereas most sites largely located in the central area of the domain have reptile communities which are more homogeneous among them. It is important to conduct long-term studies to have patterns of reptile species composition recognized as well as population decline and/or local extinctions and effective reptile conservation actions, with focus on these sites considering their unique species. Ctr Univ Cesumar, Programa Posgrad Promocao Saude, BR-87050390 Maringa, Parana, Brazil Univ Estadual Maringa, Lab Ictioparasitol, Nucleo Pesquisas Limnol Ictiol & Aquicultura, BR-87020900 Maringa, Parana, Brazil Univ Reg Cariri, Dept Ciencias Biol, BR-63105100 Crato, Ceara, Brazil Univ Fed Rio de Janeiro, Programa Posgrad Ecol, BR-21941902 Rio De Janeiro, RJ, Brazil Univ Fed Goias, Inst Ciencias Biol, Dept Ecol, Lab Herpetol & Comportamento Anim, Goiania, Go, Brazil Univ Estadual Maringa, Programa Posgrad Ecol Ambientes Aquat Continentai, BR-87020900 Maringa, Parana, Brazil Univ Fed Goias, Inst Ciencias Biol, Dept Ecol, Lab Biogeog Conservacao, BR-74001970 Goiania, Go, Brazil Univ Estadual Paulista, Dept Ciencias Biol, Fac Ciencias, BR-17033360 Bauru, SP, Brazil Univ Estadual Paulista, Dept Ciencias Biol, Fac Ciencias, BR-17033360 Bauru, SP, Brazil CNPq: 303622/2015-6 CNPq: 304363/2010-3 FAPESP: FAPESP: 2011/18510-0 Instituto Chico Mendes de Conservacao da Biodiversidade/Centro Nacional de Pesquisa e Conservacao de Repteis e Anfibios (ICMBio/RAN): 154-05

Amphibians inhabiting agricultural areas are constantly exposed to large amounts of chemicals, which reach the aquatic environment during the rainy season through runoff, drainage, and leaching. We performed a comet assay on the erythrocytes of tadpoles found in the surroundings of agricultural fields (soybean and corn crops), where there is an intense release of several kinds of pesticides in different quantities. We aimed to detect differences in the genotoxic parameters between populations collected from soybeans and cornfields, and between them and tadpoles sampled from non-agricultural areas (control group). Tadpoles collected from ponds located at soybean fields had significantly more DNA damage, followed by tadpoles collected from cornfields. In contrast, animals sampled from non-agricultural areas had the lowest incidence of DNA damage. In addition, we found a negative correlation between the parameters of the comet assay and the area of the ponds surrounding soybean. This correlation indicates a possible dilution effect in the concentration of pesticides. Finally, Physalaemus cuvieri Fitzinger, 1826 seems to be a good bioindicator for detecting the genotoxic effects of field agricultural insecticides; therefore, we suggest that this species should be used in environmental biomonitoring studies, since it is common and abundant where it occurs.

The aim of the study was to use the comet assay (single-cell gel electrophoresis) and micronucleus test to assess the extent of genomic damage in the whole blood of Dendropsophus minutus from agroecosystems with great use of agrochemicals and to compare the results to those obtained from animals living in unpolluted areas. Our results indicated that specimens of D. minutus collected in perturbed areas exhibited higher amounts of DNA damage in blood cells in comparison to animals from areas free of agricultural activities. The average and standard deviation of all comet assay parameters (tail length, percentage of DNA in the tail, and olive tail moment) and micronuclei frequency were significantly higher in specimens collected in perturbed areas than in the animals from preserved areas. Our study showed that animals from perturbed areas, such as agroecosystems, tend to have higher amounts of DNA damage than animals from reference areas. Moreover, we can conclude that D. minutus tadpoles could be included as a model organism in biomonitoring studies.

Local niche-based processes and dispersal are important determinants of assemblage composition and species diversity. However, there is no consensus about the relative importance of niche and spatial processes to explain the distribution of anuran species in tropical systems. In our study, we analyzed the niche and neutral effects on anuran assemblages and found that biotic interactions were a predictor of assemblage structure. The Eltonian concept of niche was the best predictor for the structure of aquatic-breeding anuran assemblages, as species tended to co-occur more often than would be expected by chance. We suggest that the lack of environmental effect could be explained by differences in the pattern of movement between arboreal and non-arboreal anurans. Once there is a reduction in the number of arboreal anurans in open areas, the importance of habitat heterogeneity to explain assemblage composition should decrease. The lack of correlation between the spatial component in our model and species composition is evidence that spatial processes, such as migration, did not play a major role in structuring local assemblages. Anurans are generally assumed as having poor dispersal ability, yet this assumption is not true for all anuran species. We suggest that future studies should include key behavioral traits, such as site fidelity and homing behavior, as these traits can represent the dispersal abilities of anurans and dispersal ability seems to be important when we try to predict patterns of anuran distribution.

Os girinos de anuros são elementos importantes das redes tróficas de ambientes aquáticos, sendo recurso alimentar de diversos tipos de predadores. Desta maneira, os girinos apresentam uma grande variedade de mecanismos de defesa que podem ser morfológicos, comportamentais e/ou fisiológicos. A impalatabilidade, produzida pelo acúmulo de substâncias tóxicas na pele, é um mecanismo comum em muitas linhagens de anfíbios. No entanto, alguns predadores não são afetados por estas substâncias tóxicas, o que pode favorecer o desenvolvimento de mecanismos alternativos de defesa contra predação. Neste contexto, nosso objetivo foi avaliar se girinos impalatáveis de Rhinella ornata (Spix, 1824), podem apresentar mecanismos comportamentais de defesa contra predação na presença de predadores que não são afetados pelas substâncias tóxicas em sua pele. Para testar nossa hipótese, utilizamos dois tipos de predadores aquáticos: um heteróptero aquático do gênero Belostoma e uma larva de libélula do gênero Aeshna. Os girinos foram colocados em aquários com pistas visuais e químicas dos predadores (experimento de risco direto), somente pistas químicas (experimento de risco indireto) e ausência completa de sinais de predadores (controle). Em ambos os casos, o comportamento de natação foi observado durante 5 minutos. Durante os experimentos não houve alteração no comportamento de natação dos girinos.

Leptodactylus labyrinthicus tadpoles are known predators of anuran eggs and hatchlings, but they are also able to filter-feed in the water column and scrape food off of firm substrates. We evaluated and compared these alternative feeding behaviors in relation to feeding kinematics and the shape of the mouth with high-speed digital imaging. We tested the hypotheses that (1) L. labyrinthicus tadpoles use functionally different feeding kinematics when feeding on alternative food sources and (2) that the jaw sheaths of L. labyrinthicus tadpoles deform less during filter-feeding and substrate grazing compared with more common tadpoles not so specialized for macrophagous carnivory. Our results show that filtering and scraping feeding behaviors differ significantly in both kinematics and shape of the mouth. During filter-feeding, tadpoles display longer gape cycles and attain a narrower maximum gape earlier in the cycle compared with substrate grazing. Jaw deformation during opening and closing phases of the gape cycle is more pronounced during grazing on firm substrates. This deformation contributes to the achievement of a wider maximum gape during feeding. These differences appear to reflect behavioral adjustments by the tadpoles to maximize food intake. Feeding in tadpoles of L. labyrinthicus is not restrained by their typical carnivorous morphology. On the contrary, L. labyrinthicus tadpoles seem to be opportunistic feeders able to obtain nutrients from a variety of food sources by using different feeding strategies.