Relationships between predation, breeding site choice, and palatability of larval anurans in eastern Texas.

摘要

I tested the relative palatability of twelve species of anuran larvae (tadpoles) (Acris crepitans, Bufo valliceps, B. woodhousei, Gastrophryne carolinensis, Hyla cinerea, H. versicolor, Pseudacris crucifer, P. triseriata, Rana catesbeiana, R. clamitans, R. sphenocephala , and Scaphiopus holbrookil) using four common predators (Lepomis cyanellus, L. macrochirus, Anax junius, and Procambrus nigrocinctus). Palatability was determined by presenting larvae to predators and recording the behavior of the predator to determine if the larvae were distasteful. I also tested for ontogenetic shifts in palatability in the twelve species of anuran larvae, and mapped water permanency onto a composite phylogeny of the twelve species to test for correlated patterns of evolution. Bufo valliceps, B. woodhousei, R. clamitans, and R. sphenocephala all showed substantial signs of noxiousness or unpalatability in laboratory experiments. Bufo woodhousei, R. clamitans , and R. sphenocephala all showed ontogenetic shifts in palatability to one or more predators. Bufo woodhousei shifted from being unpalatable at intermediate stages of development to being palatable during late stages when fed to bluegill and naiad predators. While R. sphenocephala shifted from being unpalatable at early stages of development to being palatable at later stages of development when fed to bluegill and naiad predators, and R. clamitans showed the same shift when fed to naiad predators. Palatability and water permanency use suggests patterns of correlated evolution in the ranids and bufonids, however the association fell short of statistical significance.