Predicting Amphibian Metamorphosis

Data presented support the hypothesis that temperature is a major proximal factor determining larval growth and differentiation patterns, and can be expressed by a modification of Belehradek's equation.

Abstract

Data are presented to test predictions of amphibian metamorphosis by a differentiation based model. Differentiation rates account for 95% of the variance in the length of the larval period, while growth rates account for less than 50% of the variance. The probability of completing metamorphosis at a given time is a function of current developmental stage and of differentiation rate. Growth parameters are poor predictors of metamorphosis, because the relationship between growth and differentiation varies as a function of the abiotic and biotic environment. Differentiation rate, growth rate, and stage-specific growth can be expressed as functions of environmental parameters such as temperature and density. Data presented support the hypothesis that temperature is a major proximal factor determining larval growth and differentiation patterns. Temperature effects on developmental rates during metamorphosis can be expressed by a modification of Belehradek's equation, previously applied only to embryonic development.