Meeting Abstract

3-3  Thursday, Jan. 5 08:45 – 09:00  Tumbling Pass: Sand Dollar Larvae Show Genetic Variation for Their Turbulence Responses at Settlement FERNER, MC*; HODIN, J*; NG, G; LOWE, CJ; GAYLORD, B; SFSU and Romburg Tiburon Center, CA, USA; Friday Harbor Labs, U. of Washington, USA; Bodega Marine Lab, UC Davis, CA, USA; Hopkins Marine Station of Stanford U., CA, USA; Bodega Marine Lab, UC Davis, CA, USA larvador@uw.edu http://staff.washington.edu/hodin/publications.html

Sea shore animals and non-animals are often characterized by complex life cycles involving a planktonic dispersal period followed by settlement and metamorphosis back into shoreline benthic habitat. Underlying this common strategy in animals are substantial differences, even in closely related species, in the cues that their dispersing larvae use to positively identify suitable nearshore habitat for their generally irreversible transformation. The vast majority of studies on such ‘settlement cues’ to date have focused on olfactory stimuli to which larvae respond – including compounds produced by algae, conspecifics or bacterial biofilms. Here we report on intraspecific variation for larval responses to an entirely different class of settlement stimulus: nearshore turbulence. We have previously shown that larvae of sea urchins and sand dollars (including the Pacific sand dollar, Dendraster excentricus) show hastened onset of settlement following exposure to turbulence of an intensity characteristic of wave impacted shores. Here we show that larval offspring of certain D. excentricus parents (either male or female) show consistently enhanced responses to turbulence when compared to larvae deriving from different parents. In other words, there is within population genetic variation for the turbulence responses in this species. We will consider this finding both in terms of the possible advantages of bet hedging with respect to settlement decisions as well as variation in turbulence responses as a plausible mechanism of speciation.