Abstracts (first author)
Plastic traits of whitefish dependent on the interaction of pathogens, host developmental stage, and genetics
Phenotypic plasticity may evolve in response to environmental changes in populations with sufficient genetic variation for the reaction norms. We used the whitefish Coregonus palaea to experimentally study the interplay of ecology, genetics, and development on the evolutionary potential of plastic traits. In order to disentangle maternal from paternal contributions, and the likely effects of developmental stage from ecological effects, we sampled a natural population, used gametes for full-factorial in vitro fertilizations, raised the resulting offspring singly at controlled conditions, and exposed them at one of several points during development to the opportunistic pathogen, Pseudomonas fluorescens. Inoculation with the bacterium increased embryonic mortality and resulted in delayed hatching of smaller, less developed larvae. Vulnerability to infection increased distinctly over embryo development. This change coincided with a shift in the importance of maternal to additive genetic effects on survival. Timing of exposure also affected whether there was genetic variability for trait plasticity, and whether traits were correlated across environments. Our results demonstrate that additive genetic effects on plastic traits and of trait plasticities critically depend on developmental stage and hence on the timing of a stressful event.