| dc.description.abstract | Prey often induce changes in the phenotype of their prey through phenotypic plasticity. Phenotypes that change include life history traits, morphology, and behavior, and changes may be adaptive or non-adaptive. The goal of this dissertation was to test hypotheses about predator-induced phenotypic plasticity related to the timing of predation exposure, differences between maternal and paternal effects, the effects of resource availability on plasticity, and the effect of predation cues on mating behavior. To address these questions, I exposed pond snails (Physa acuta) to cues from predators (crayfish, Procambarus sp.), and measured aspects of their life history, morphology, and behavior. In chapter 1, I found evidence that the effects of predator cues on snails depend on when the snails are exposed. Snails exposed to predator cues early in life experienced a delay in reproduction, laid fewer eggs, and had reduced life expectancy. Interestingly, these effects remained the same whether the cues were removed post-reproduction or not, and suggests changes in life history may be maladaptive response to early life stress. In chapter 2, I found snails exposed to food restrictions or predator cues responded less to predation cues than control snails, as predicted by theory. I found some evidence of predator-induced parental effects in the offspring of predator exposed snails, but they did not fully match modelling predictions from the literature. In chapter 3, I found evidence that control snails are less likely to mate with predator exposed snails than with other control snails, but that if they did mate, the length of the mating was not affected. These results have implications for the interpretation of parental effect experiments. Overall, within generation plasticity was well predicted by existing theory, while transgenerational plasticity was more difficult to predict. This suggests that more mechanistic studies may be needed to fully understand transgenerational plasticity. | |
