Disgusting or delicious? Predatory behavior of the hylid frog Phyllodytes luteolus on sympatric ants

Abstract

ABSTRACT. The phytotelm-dwelling frogs from the genus Phyllodytes Wagler, 1830 have been characterized as specialist frogs regarding their diet strategy which is mainly composed by colonial insects. Herein, we used two species of ants (Camponotus sp. and Gnamptogenys sp.) with distinct defensive mechanisms to test the predatory behavior of Phyllodytes luteolus Wied, 1824. The experiment was conducted with frogs inhabiting a patch of 20 bromeliads (Aechmea cf. blanchetiana). Ants were off ered randomly to the frogs until we obtained ten observations of predation of each ant species. We observed and recorded the time that P. luteolus needed to keep each ant species inside its mouth before it could ingest it. Predatory behavior was highly distinct. While Camponotus were caught and swallowed within six seconds and without apparent discomfort, individuals of P. luteolus had more diffi culty in swallowing Gnamptogenys individuals, the time of manipulation ranging from 57 to 177 seconds. The mean values of time of predation observed in each treatment was highly signifi cant (p<0.001). We conclude that diff erences found in the time of manipulation are highly correlated with defense mechanisms of each species of ants.KEYWORDS. Behavior, Camponotus, Gnamptogenys, bromeliads, predation.RESUMO. Nojento ou delicioso? Comportamento predatório da perereca Phyllodytes luteolus sobre formigas simpátricas. As pererecas que habitam fi totelmatas do gênero Phyllodytes Wagler, 1830 têm sido caracterizadas como especialistas em relação à sua estratégia de dieta, que é composta principalmente por insetos coloniais. Neste trabalho, usamos duas espécies de formigas (Camponotus sp. e Gnamptogenys sp.) com mecanismos de defesa diferentes para testar o comportamento predatório de Phyllodytes luteolus Wied, 1824. O experimento foi conduzido com pererecas que habitavam uma mancha de 20 bromélias (Aechmea cf. blanchetiana). As formigas foram oferecidas aleatoriamente para as pererecas até que obtivemos dez observações de predação para cada espécie de formiga. Observamos e registramos o tempo que P. luteolus precisou manter cada espécie de formiga dentro da boca antes da mesma poder ser ingerida. O comportamento de predação foi altamente distinto. Enquanto Camponotus foram capturadas e engolidas dentro de seis segundos e sem desconforto aparente, indivíduos de P. luteolus tiveram maiores difi culdades em engolir indivíduos de Gnamptogenys, com tempo de manipulação variando de 57 a 177 segundos. Os valores médios do tempo de predação em cada tratamento foram altamente signifi cativos (p<0.001). Concluímos que as diferenças encontradas no tempo de manipulação estão altamente correlacionadas com os mecanismos de defesa de cada espécie de formiga.

Diet of bromeliad-frog Phyllodytes luteolus (Anura, Hylidae) in Atlantic Forest environments: what have the frogs been eating outside sandy coastal plains?

“…The diet of P. luteolus was composed exclusively of arthropods, and ants were the most consumed prey in number, frequency and volume in environments sampled. The high importance of ants in the diet of P. luteolus was also observed in other sandy coastal plains in Espírito Santo State (Ferreira et al, 2012;Motta-Tavares et al, 2016) and Bahia (Motta-Tavares et al, 2016;Solé & Loebmann, 2017). Because of the high consumption of ants and termites, P. luteolus has been considered to be specialized with regards to its diet (colonial insects) and foraging strategies (Ferreira et al, 2012).…”