OYARZUN, F.X.*; HALANYCH, K.; SWALLA, B.; University of Washington; Auburn University; University of Washington: Molecular Phylogeography and Reproductivion of the Poecilogonous Polychaetes ““Boccardia proboscidea”” and ““B. wellingtonensis”” (Polychaeta: Spionidae): Two worms and Two hemispheres

Poecilogony is the ability to alternate between multiple developmental modes. Although rare, poecilognous species are useful models to study reproductive tradeoffs without the complications of historical interspecific differences. The goal of this study was first to construct a molecular phylogeny of several populations of two poecilogonous species, ““Boccardia proboscidea”” and ““Boccardia wellingtonensis”“, from the west coast of North and South America respectively, to provide an evolutionary framework in which to examine variation in reproductive traits along latitudinal gradients. Secondly, a comparison of reproductive strategies between these species was made. The phylogenetic analysis based on two genes, 16S and Cyt B, showed that the two species diverged by 6%. Both species have several distinctive haplotypes in their populations, but within each species there was no geographic relation of these differences suggesting that are due to phenotypic plasticity. The two species produce capsules that contain nurse eggs, and two types of larvae; however, differences were found in capsule dynamics, number of nurse egg, and number and type of embryos produce in the two species which could potentially result in sibling conflict due to cannibalisms and competition for nurse eggs. The role of maternal brooding behavior in these two systems is discussed based on preliminary data. This study constitutes a first step in building an evolutionary framework for comparing (1) intracapsular dynamics and sibling conflict, (2) maternal brooding behavior, and (3) population demographics data, in two sibling poecilogonous species in both hemispheres.