Predator-induced phenotypic plasticity in tadpoles: extension or innovation?
Phenotypic plasticity, the ability of a trait to change as a function of the environment, is central to many ideas in evolutionary biology. A special case of phenotypic plasticity observed in many organisms is mediated by their natural predators. Here, we used a predator-prey system of dragonfly larvae and tadpoles to determine if predator-mediated phenotypic plasticity provides a novel way of surviving in the presence of predators (an innovation) or if it represents a simple extension of the way noninduced tadpoles survive predation. Tadpoles of Limnodynastes peronii were raised in the presence and absence of predation, which then entered a survival experiment. Induced morphological traits, primarily tail height and tail muscle height, were found to be under selection, indicating that predator-mediated phenotypic plasticity may be adaptive. Although predator-induced animals survived better, the multivariate linear selection gradients were similar between the two tadpole groups, suggesting that predator-mediated phenotypic plasticity is an extension of existing survival strategies. In addition, nonlinear selection gradients indicated a cost of predator-induced plasticity that may limit the ability of phenotypic plasticity to enhance survival in the presence of predators.
Kraft
P G
PG
School of Integrative Biology, University of Queensland, Brisbane, Australia. pkraft@zoology.uq.edu.au
Franklin
C E
CE
Blows
M W
MW
D000818:Animals; D005075:Biological Evolution; D049628:Body Size; D005106:Exploratory Behavior / Q000502:physiology*; D007814:Larva / Q000502:physiology; D008954:Models, Biological; D018482:Muscle, Skeletal / Q000033:anatomy & histology; D010641:Phenotype; D010809:Physical Fitness; D011235:Predatory Behavior; D011898:Ranidae / Q000033:anatomy & histology / Q000254:growth & development / Q000502:physiology*; D013623:Tail / Q000033:anatomy & histology