Predator-Induced Phenotypic Plasticity in Organisms with Complex Life Histories

Predator-induced phenotypic plasticity is widespread in nature and includes variation in life history, morphology, and behavior. In organisms with complex life histories, predator-induced phenotypic plasticity in the larval period has been widely documented. Several models predict how organisms should alter their size at and time to metamorphosis in response to an increased risk of predation. A survey of empirical studies finds that these theoretical predictions are frequently met. However, no one model performs the best. Additionally, there are several results not predicted by any model. Predator-induced plasticity in metamorphic traits may be related to predator-induced changes in larval morphology and behavior. Predictions of predator effects on larval traits are generally met, except for direct costs of predator-induced morphological phenotypes. Future work should incorporate more detailed studies of growth rate, morphology, and behavior during the larval period, as well as studies of size-specific mortality rates in the presence and absence of predators.