Variable Responses to Rainfall by Breeding Tungara Frogs
Though many amphibians breed in response to rainfall, rainfall can create substantial risks as well as benefits. For species that breed in ephemeral ponds and puddles, heavy rainfall can create many “false” ponds that quickly desiccate, particularly in wet years. As a result, nightly responses to rainfall may vary depending on seasonal or yearly rainfall. I used two years of data and previous studies to demonstrate variation in response to rainfall by breeding Tungara Frogs (Physalaemus pustulosus) on Barro Colorado Island, Panama. In 1997, an unusually dry year, breeding tungara frogs were far more abundant on wet nights than on dry nights. In 1998, an average year for rainfall, tungara frogs exhibited no significant response to rainfall and even a trend toward greater abundance on dry nights. In addition, female frogs were more sensitive to the effects of rainfall than were males. As a result, mating system parameters were highly dependent on both nightly and yearly rainfall.Abstract
Tungara frog responses to rainfall in 1997 (A) and 1998 (B). Open bars represent dry nights, and shaded bars represent wet nights. * indicates P < 0.05, ** indicates P < 0.001. Error bars indicate ± 2 SE
Relationship between the nightly ratio of females to males and the nightly number of males observed at a series of artificial ponds