Meeting Abstract

P1.88  Thursday, Jan. 3  Attack on the Clones: Predator-Induced Cloning in Echinoderm Larvae VAUGHN, Dawn; University of Washington, Friday Harbor Laboratories dvaughn@u.washington.edu

Asexual reproduction (cloning) is widespread among planktonic echinoderm larvae, with most reports for advanced larval stages. Larval cloning has been observed in diverse circumstances, which has suggested diverse adaptive consequences. Hypotheses of the advantages of larval cloning and the stimuli that induce cloning in larvae have emphasized increased fecundity or dispersal. This study, in contrast, shows that larvae of the sand dollar Dendraster excentricus clone at early stages in response to stimuli from predators. The asexual reproduction occurs by budding and fission and the resulting clones are smaller than early stage sibling larvae developed from eggs. Some products of cloning remained small as they developed to advanced stages with the rudiment of a juvenile sand dollar. This decrease in size at a given developmental stage suggests a strategy against visual predators, and perhaps decreased signals to some non-visual predators. Additionally, predator-induced cloning and the retention of small larval size suggests that size-fecundity trade-offs influencing reproductive allocation can be readjusted based on information available to the offspring but not to the mother. For larvae, stimuli in the plankton can indicate conditions favorable for growth or dispersal, or as shown here, circumstances that in the absence of cloning may otherwise be grim. These results offer a new context for the ecology of larval cloning with both the stimulus and stage at response indicating additional, unsuspected advantages of cloning.