Aspects of Tolerance to Desiccation in Acris crepitans and Pseudacris streckeri

Abstract

In terms of per cent body water, tolerance to body water loss, size and shape, P. streckeri appears to be much better adapted for a terrestrial mode of life. It also appears that P. streckeri can tolerate a greater loss of body water than any North American hylid thus far examined. It is hypothesized that the dependence on relatively permanent bodies of water by A. crepitans and the semi-fossorial habitus of P. streckeri make these species relatively unresponsive on a population basis to decreasing rainfall regimes when compared to other hylid frogs. Neither species increases in size or increases in tolerance to body water loss with decreased annual rainfall; both show increased per cent body water with decreased rainfall. Populations of a species of Hyla show increased body size, increased per cent body water and sharply increased tolerance to body water loss through less of a decrease in annual rainfall. It is shown that population differences in parameters of water economy in many cases exceed the differences found between species and even genera in earlier studies. It is suggested that comparative surveys of anuran water economy need to be interpreted with this consideration in mind.