Relative Palatabilities of Members of a Larval Amphibian Community

Abstract

The palatability of seven species of amphibian larvae (Rana sylvatica, R. palustris, R. clamitans, Hyla crucifer, Bufo americanus, Ambystoma maculatum and Notophthalmus viridescens) in a community was assessed using the major predator in the community, the larvae of the predaceous diving beetle Dytiscus verticalis. Premetamorphic stages of all species were fully palatable to the beetle larvae while metamorphic stages of R. sylvatica, R. palustris, B. americanus, A. maculatum and N. viridescens were rejected as food. Survival of these late metamorphic stages does not correlate with increase in size but does correlate (in R. sylvatica) with the development of granular glands in the skin. It appears that the amphibian larvae in this community represent a spectrum of palatability to the beetle larvae. The palatability of any species to a predator is relative to the presence and abundance of other prey species.