Body Size and Life History Traits in Native and Introduced Populations of Coqui Frogs

Abstract

Introduced populations often exhibit rapid phenotypic changes following colonization of new environments. These changes, which often contribute to the successful establishment and spread of introduced species, may result from evolution or phenotypic plasticity. We studied variation in adult body size across elevational gradients in native (Puerto Rico) and introduced (Hawaii) populations of Coquis (Eleutherodactylus coqui). To explore the possible mechanisms underlying variation in adult body size, we conducted a laboratory common-environment experiment to study the effects of temperature (19°C and 25°C), elevation ( 700 m), and area (two in Puerto Rico and one in Hawaii) on five size-related life history traits: clutch size, egg size, hatching size, size at 30 days, and growth rate. In the field in both Puerto Rico and Hawaii, body size was positively correlated with elevation, which is negatively correlated with temperature, but the magnitude of the slope was greater in Puerto Rico than in Ha...