Meeting Abstract

33.2  Jan. 5  Plasticity in Brooding Time of a Species with Alternative Reproductive Modes OYARZUN, FX*; BRAVO, MJ; University of Washington; University of Washington foyarzun@u.washington.edu

Species with alternative reproductive modes are rare, but serve as excellent models to study reproductive tradeoffs without phylogenetic confounding factors. Boccardia proboscidea (Polychaeta: Spionidae) has two main reproductive modes: some females produce only planktotrophic larvae while others produce a mix of planktotrophic larvae, nurse eggs and adelphophagic larvae. Females actively care for the capsules with embryos and at some point take the decision of opening the capsules to hatch the larvae. The hatching time of the larvae may have important effects on the dispersal and survival of larvae and the population dynamics, especially in cases of a mixed reproductive mode with intracapsular sibling cannibalism. In addition, populations of B. proboscidea vary geographically in reproductive modes. The populations from the north of the Pacific coast of North America reproduce only with the mixed reproductive mode; populations from the south have both reproductive modes, that solely with planktotrophs and no cannibalism being the most common. The goal of the study was first to test, in common garden conditions, if the females from the northern and southern populations differ in number of capsules and in the nurse egg to larva ratios, then to test whether the timing of the decision of the mother to open the capsules is plastic and whether this response is different in females with different reproductive modes.