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Amphibian invasions have considerable detrimental impacts on recipient ecosystems; however, reliable risk analysis of invasive amphibians still requires research on more non-native amphibian species. An invasive population of the Indian bullfrog, Hoplobatrachus tigerinus, is currently spreading on the Andaman archipelago and may have significant trophic impacts on native anurans through competition and predation. We assessed the diet of the invasive Hoplobatrachus tigerinus (n = 358), the native Limnonectes spp. (n = 375) and Fejervarya spp. (n = 65) in three sites, across four habitat types and two seasons, on the Andaman archipelago. We found a significant dietary overlap of H. tigerinus with Limnonectes spp., which may lead to competition. Small vertebrates, including several endemic species, constituted a majority of H. tigerinus diet by volume, suggesting potential impact by predation. Diets of the three species were mostly governed by the positive relationship between predator-prey body sizes. Niche breadth analyses did not indicate any significant changes in diet between seasons. Hoplobatrachus tigerinus and Fejervarya spp. chose evasive prey, suggesting that these two species are mostly ambush predators; Limnonectes spp. elected sedentary prey; although a large portion of its diet consisted of other prey types, such electivity indicates ‘active search’ as its major foraging strategy. All three species of anurans mostly consumed terrestrial prey. This intensive study on a new genus of invasive amphibian contributes to the knowledge on impacts of amphibian invasions, and elucidates the feeding ecology of H. tigerinus, and species of the genera Limnonectes and Fejervarya. We stress on the necessity to evaluate prey availability and volume in future studies for meaningful insights into diet of amphibians.
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Raw dataset on diet of invasive Hoplobarachus tigerinus and three species of anurans on the Andaman archipelago
Body measurements of individual frogs (SVL - Snout vent length, HW - head width, LJL - Lower jaw length) and associated prey taxa, type, prey morphology.