Predation‐induced plasticity in metamorphic duration inXenopus laevis

Abstract

Summary 1. Many organisms are able to vary the duration of life-history stages in response to environmental conditions such as predation risk. However, in those undergoing a metamorphosis, it is not known whether the duration of the metamorphic phase itself can change in response to the presence of a predator, and whether this carries costs. 2. In experiments using the amphibian Xenopus laevis , we found that metamorphosis was accelerated in the presence of a predator and this occurred consistently across the natural range of temperatures experienced by Xenopus . 3. Although metamorphic climax was reduced in duration, a functional tail was maintained for longer in the presence of a predator. Furthermore, burst swimming speed was significantly faster for animals metamorphosing in the presence than in the absence of a predator. This suggests that the more rapid development induced by predator presence does not carry costs in terms of ability to escape predators during metamorphosis. 4. There was no evidence of post-metamorphic costs of faster metamorphic climax in terms of escape response since juveniles from the two predator treatments did not differ in burst swimming speed. However, individuals metamorphosing in the presence of predators lost proportionally more mass during metamorphosis, resulting in smaller juveniles than those without predators. This reduced juvenile size represents a potential cost of accelerating metamorphic development. 5. Therefore, conditions experienced during metamorphic climax, independent of larval conditions, can have a significant influence on the life histories of animals with complex life cycles.