Living in a same microhabitat should means eating the same food? Diet and trophic niche of sympatric leaf-litter frogs Ischnocnema henselii and Adenomera marmorata in a forest of Southern Brazil (original) (raw)
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Food niche overlap between two sympatric leaf-litter frog species from Central Amazonia
Zoologia (Curitiba), 2012
We studied the feeding habits and similarities in the diet of two sympatric and syntopic Amazonian frog species, Anomaloglossus stepheni (Aromobatidae) and Leptodactylus andreae (Leptodactylidae) in a forested area in Central Amazonia. The breadth of the trophic niche of these species was 5.89 and 3.75, respectively, and approximately 85% of their diets were similar. Ants were main food item in the diets of both frog species. The coexistence between these frog species may be facilitated by the significant differences in the size of their mouths. This difference allows them to consume preys items of different sizes.
Food niche overlap between two sympatric leaf-litter frog species from Central Amazonia.pdf
We studied the feeding habits and similarities in the diet of two sympatric and syntopic Amazonian frog species, Anomaloglossus stepheni (Aromobatidae) and Leptodactylus andreae (Leptodactylidae) in a forested area in Central Amazonia. The breadth of the trophic niche of these species was 5.89 and 3.75, respectively, and approximately 85% of their diets were similar. Ants were main food item in the diets of both frog species. The coexistence between these frog species may be facilitated by the significant differences in the size of their mouths. This difference allows them to consume preys items of different sizes.
Herpetological Journal
We analysed the diet, pattern dispersion, calling activity and microhabitat use of the leptodactylid frog Adenomera marmorata at an Atlantic rainforest site on Ilha Grande, in southeastern Brazil. Adenomera marmorata is endemic to the Brazilian Atlantic rainforest biome, occurring in the leaf litter of forests from Rio de Janeiro state to Santa Catarina state, and this is the first ecological study of the species. It has a clumped pattern of dispersion along the forest floor. Calling activity extended from dusk to dawn, although on rainy days some individuals remained active during the daylight period. The individuals collected for diet analysis were most frequently found on the leaf-litter surface and under the leaf litter of the forest floor. Of the six potential microhabitat categories we recorded, A. marmorata used only two (leaf litter and fallen branch). We conclude that in the Atlantic forest of Ilha Grande, A. marmorata possesses crepuscularnocturnal calling activity, and is exclusively associated with the leaf litter of the forest floor where it feeds predominantly on isopods, ants and insect larvae.
Intrapopulation Diet Variation in Four Frogs (Leptodactylidae) of the Brazilian Savannah
Copeia, 2007
Age and sex-based as well as individual-level diet variation are known to occur in many natural populations, and may have important ecological and evolutionary implications. In the case of individual-level diet variation, most examples come from species-poor, temperate communities, and it is currently believed that it results from population niche expansion following interspecific competitive release. We investigated and measured the intrapopulation diet variation in four species of frogs, Leptodactylus (=Adenomera) sp., Eleutherodactylus cf. juipoca, L. fuscus, and Proceratophrys sp., that are part of species-rich frog communities of the Brazilian Cerrado. Specifically, we investigated age and sex-related, as well as individual-level, diet variation. We measured individual-level diet variation with the IS index of individual specialization, which is a measure of the degree of overlap between individual niches and the population niches. We found no ontogenetic shifts or sex-related differences in the types of prey consumed. However, we found evidence of individual-level diet variation in the four studied species (IS~0.2-0.5). There was a negative correlation between IS and the population niche width (r = -0.980; P < 0.0001), indicating that interindividual diet variation is more pronounced in more generalized populations. This pattern suggests that individual niche widths remain constrained even when population niche breadth is wide, consistent with the presence of functional trade-offs. We found no evidence that these trade-offs arise from morphology, since there was no diet-morphology correlation. We hypothesize that trade-offs have a behavioral or physiological basis, which needs further investigation. This is the first documented case of individual-level diet variation in a diverse tropical community, indicating that this phenomenon is not restricted to competitive release-driven niche expansion in temperate, depauperate communities.
Brazilian Journal of Biology, 2010
We studied the feeding ecology of two Hylinae anurans (Hypsiboas raniceps and Scinax acuminatus), living sympatrically and syntopically in the Pantanal of Miranda, Mato Grosso do Sul State, Brazil. The two hylid species had similar relative mouth width but differed in body size. The diet of the two frog species were composed of arthropodan prey. Both species consumed 11 different prey types, of which seven were common among them. Hypsiboas raniceps had a larger niche breadth (B A = 0.64) than S. acuminatus (B A = 0.48). Trophic niche overlap among frog species was 60.7 %. Our data are suggestive that although for many anurans the diet simply tend to reflect prey availability in the microhabitat, these two frog species, despite sharing similar microhabitat and period of activity (thus potentially exposed to a similar array of preys), tends to differ somewhat in diet (about 40%) which may result from some intrinsic ecological aspects to each of them (e.g. ecophysiology) and/or differe...
We studied the feeding habits and microhabitat use of the Amazonian frogs Hyla minuta and Pseudopaludicula sp. at Serra Norte, Carajás, Brazil. Although living syntopically, the two species differed markedly in both prey types and sizes. Standardized feeding niche breadth of H. minuta (B st = 0.572) was larger than that of Pseudopaludicula sp. (B st = 0.149) and their feeding niche overlap was considerably low (10.5%). The two frog species also differed in microhabitat use. When active, Pseudopaludicula sp. were found partially submerged at the lake border whereas H. minuta were found predominantly on Nymphaea sp. leaves. Although we have not evaluated taxonomic effects on diet composition, differences in diet may be partially explained by differences in microhabitat use and frogs' size. RESUMO Hábitos alimentares e uso do microhabitat por duas espécies sintópicas de anuros amazônicos (Hyla minuta e Pseudopaludicula sp. (gr. Falcipes) Nós estudamos os hábitos alimentares e o uso do microhábitat pelos anuros amazônicos Hyla minuta e Pseudopaludicula sp. em Serra Norte, Carajás, Brasil. Apesar de serem sintópicas, as duas espécies diferiram acentuadamente nos tipos e tamanhos de presas consumidas. A largura padronizada do nicho alimentar de H. minuta (B st = 0,.572) foi maior do que a de Pseudopaludicula sp. (B st = 0,149) e a sobre-posição do nicho alimentar foi relativamente baixa (10,5%). As duas espécies de anuros também diferiram acentuadamente em relação ao uso do microhábitat. Quando em atividade, os indivíduos de Pseudopaludicula sp. eram encontrados parcialmente submersos próximo à margem do lago, enquanto os indivíduos de H. minuta eram encontrados predominantmente sobre folhas de Nymphaea sp. Apesar de não termos avaliado efeitos da taxonomia sobre a composição da dieta, as diferenças encontradas na dieta podem ser parcialmente explicadas por diferenças no uso do microhábitat e tamanho dos anuros. Palavras-chave: dieta, anuros, partição de recursos, sintopia. As pointed out by Duellman & Trueb (1986), there is little information concerning the feeding habits of amphibians and the few data that are available are mostly anedoctal. Sympa-tric species may be subject to a similar spectrum of potential prey, but not necessarily feed on the same items, due to differences in taxonomy, patterns of microhabitat use, or body size.
Haddadus binotatus is an endemic anuran of the Brazilian Atlantic Forest and currently, there is no information about the diet of this species. We analyzed the diet of two populations of this anuran in two states in southeast Brazil. Samplings were carried out in 2004 in the state of Rio de Janeiro and in 2009 and 2010 in the state of Espírito Santo. Haddadus binotatus presented a rich diet composition, preying 19 prey types. Orthoptera, Coleoptera, and Blattodea were the most important preys in the Rio de Janeiro population, and Orthoptera, Araneae and Hemiptera were the most important in the Espírito Santo population. The diet composition differed numerically between the two localities, but not in terms of volume, which can reflect local differences in the prey availability in the two habitats. The jaw width limited the size of prey, which is expected for predators who swallow the preys without chewing. The proportion of individuals with empty stomachs was higher in the Rio de Janeiro population (39.2%) than in the Espírito Santo population (17.9%), suggesting that the former could be in a lower energy balance. The females of the species were larger than the males, which may result from the production of larger eggs.
Individual-level diet variation in four species of Brazilian frogs
Journal of Animal Ecology, 2009
Many natural populations exploiting a wide range of resources are actually composed of relatively specialized individuals. 2. This interindividual variation is thought to be a consequence of the invasion of 'empty' niches in depauperate communities, generally in temperate regions. If individual niches are constrained by functional trade-offs, the expansion of the population niche is only achieved by an increase in interindividual variation, consistent with the 'niche variation hypothesis'. 3. According to this hypothesis, we should not expect interindividual variation in species belonging to highly diverse, packed communities. 4. In the present study, we measured the degree of interindividual diet variation in four species of frogs of the highly diverse Brazilian Cerrado, using both gut contents and δ 13 C stable isotopes. 5. We found evidence of significant diet variation in the four species, indicating that this phenomenon is not restricted to depauperate communities in temperate regions. 6. The lack of correlations between the frogs' morphology and diet indicate that trade-offs do not depend on the morphological characters measured here and are probably not biomechanical. The nature of the trade-offs remains unknown, but are likely to be cognitive or physiological. 7. Finally, we found a positive correlation between the population niche width and the degree of diet variation, but a null model showed that this correlation can be generated by individuals sampling randomly from a common set of resources. Therefore, albeit consistent with, our results cannot be taken as evidence in favour of the niche variation hypothesis.
Herpetology Notes, 2017
Comparative studies of the diet of ecologically and phylogenetically close-related species assist in understanding the evolutionary processes underlying feeding specialization. The frogs Physalaemus lisei (Braun’s Dwarf Frog) and P. gracilis (Graceful Dwarf Frog) are good models for comparative diet studies because they occur in sympatry in several forest environments of Brazil. In this study we evaluated the gastrointestinal content of 83 individuals of these two species. We registered 12 prey categories in the diet of P. gracilis, and 19 in the diet of P. lisei. Formicidae was the most important prey category in the diet of both species, followed by Coleoptera and Araneae. Despite the high importance of ants in the diet of both species, as assessed by the Index of Relative Importance, Coleoptera presented the highest volumetric contribution. Both species presented a similar trophic niche breadth and a high diet overlap. Our results indicate similarities in the diet composition and foraging behavior of P. lisei and P. gracilis.