Meeting Abstract

P1.87  Thursday, Jan. 3  A test for transgenerational plasticity in the heat stress tolerance of intertidal embryos PODOLSKY, R.D.; College of Charleston, SC podolskyr@cofc.edu

Models of the evolution of phenotypic plasticity predict that plastic responses can evolve when organisms have predictive information about future environmental conditions and can respond on an appropriate time scale. Early developmental stages, however, may not be able to respond effectively if they have not had sufficient exposure to recent conditions or they lack molecular mechanisms involved in a response. For example, many animals lack the ability to produce embryonic transcripts for an extended period after fertilization, constraining the ability of early stages to respond to unpredictable conditions. In such cases, maternal effects could provide a form of transgenerational plasticity, such that environmental conditions experienced by adults influence non-genetic features passed to offspring that affect their ability to tolerate similar conditions. I tested for such effects in Melanochlamys diomedea, an intertidal gastropod that deposits egg masses in soft-sediment tide pools. Embryos in masses regularly experience heat stress but lack the ability to synthesize heat shock proteins (HSPs) for one or two tidal cycles, after which the HSP response gradually strengthens. In the laboratory I exposed adults to diel tidal temperature profiles distinguished by the peak temperature: several degrees below the HSP threshold, at the threshold, or several degrees above the threshold. Egg masses deposited by these adults in a common garden were then subdivided and exposed to the same three temperature profile treatments to measure the effects of adult exposure on offspring performance. The analysis presented will constitute a test of whether, under appropriate time scales, trangenerational plasticity offers a mechanism for overcoming constrains on phenotypic plasticity during early development.