Intraspecific interactions among oophagous tadpoles (Chirixalus eiffingeri: Rhacophoridae) living in bamboo stumps in Taiwan

Abstract

We studied the intraspecific interactions among oophagous Chirixalus eiffingeri tadpoles that occupied the same water-filled bamboo stumps at Chitou, Taiwan. We monitored the growth of newly-hatched tadpoles in unoccupied and occupied bamboo stumps in the field where the latter contained large tadpoles that hatched from earlier clutches. The growth of the small, late-hatching tadpoles in occupied nests was suppressed by the presence of large, early-hatching tadpoles. However, small tadpoles that were physically separated from large tadpoles in a perforated container grew at about the same rate as small tadpoles living in pools without large tadpoles. Thus, the slower growth of the late-hatching tadpoles was probably caused by behavioural interference competition with the early-hatching tadpoles. In the laboratory, we kept large and small tadpoles together in containers and did not feed them for 6 days. The large tadpoles did not cannibalize the small tadpoles. Although large tadpoles may scavenge dead tadpoles, the effects of scavenging on growth were negligible. Interactions among cohabiting C. eiffingeri tadpoles are similar to those among the oophagous tadpoles of several hylid species that use phytotelmata. Results suggest that behavioural interference competition is the principal type of intraspecific interactions among the oophagous, non-predatory tadpoles of hylid and rhacophorid frogs.