What Do Co-Mimics eat? Trophic Ecology of Ameerega pulchripecta (Anura, Dendrobatidae) and Allobates femoralis (Anura, Aromobatidae) in Eastern Brazilian Amazonia
Differentiation in resource use by sympatric species reduces competition and allows coexistence. Constraints imposed both by evolutionary history and current ecological interactions strongly influence the coexistence of distinct anuran species. In this context, we analyzed the dietary habits of two sympatric frogs in a Batesian mimicry system, Ameerega pulchripecta and Allobates femoralis, to assess potential resource overlap and competition between them. We explored the hypothesis that differences in feeding behavior and prey choice reflect these species’ status as co-mimics in a Batesian system because toxicity in anurans is strongly related to diet. We obtained stomach contents by applying the stomach-flushing technique and data on prey availability through pitfall traps arranged along both sides of the trail where the sympatric species occur. We found that the toxic A. pulchripecta actively selects ants and mites as prey, while the nontoxic A. femoralis feeds opportunistically on beetles, ants, and other sedentary prey such as larval insects and adult spiders. Based on dissimilarity, diversity, electivity, and evenness analysis we concluded that the two frog species exhibited a significant difference in prey composition. We suggest that these differences found in the feeding habits are important to the syntopic coexistence of these two frog species in our study area.Abstract
Map showing the location of Parque Natural Municipal do Cancão, Municipality of Serra do Navio, state of Amapá, Brazil (A) and sampling plot of the two frogs, (B) Ameerega pulchripecta and (C) Allobates femoralis.
Ant genera composition between Ameerega pulchripecta and Allobates femoralis in the municipality of Serra do Navio, Amapá, Brazil. Bars represent the relative frequency (%) of each genus.
Network of interactions between prey and the two frog predators, Allobates femoralis and Ameerega pulchripecta, in Serra do Navio municipality, Amapá, Brazil. The gray bar width represents the number of interactions observed per species and prey categories (i.e., the relative frequency each prey category consumed). The corresponding colored bar represents the proportion of each prey category in the diet of both species.
Relationship between the two axes generated after nonmetric multidimensional scaling (NMDS) ordination, summarizing 118 sampled stomachs. Red circles represent samples of Allobates femoralis. Blue circles represent samples of Ameerega pulchripecta.
Ivlev’s Electivity Index for each prey category by Allobates femoralis and Ameerega pulchripecta in Serra do Navio municipality, Amapá, Brazil. Abbreviations: Acari (Ac), Aranae (Ar), Coleoptera (Cp), larval Coleoptera (CpL), Collembola (Cb), Diptera (Dp), Hemiptera (Hp), Hymenoptera (Hyp), Formicidae (Fm), Orthoptera (Op).
Feeding strategy of Allobates femoralis (A, B) and Ameerega pulchripecta (C, D) in Serra do Navio municipality, Amapá, Brazil, according to prey-specific abundance (%) and frequency of occurrence (%) of each prey category in the wet (A, C) and dry (B, D) seasons, and diagram for feeding strategy interpretation considering prey importance (rare to dominant), niche width contribution (BPC = between-phenotype component; WPC = within-phenotype component) and feeding strategy (E; based on Amundsen et al., 1996).
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