Abstracts (first author)
Temporal population genetic patterns in a polychaete with multiple larval developmental modes
Many marine invertebrates have complex life cycles in which in one or more larval stages precede the adult stage. The larval developmental mode of a species can affect population dynamics through differences in fecundity, larval mortality and dispersal potential. Developmental mode may also affect temporal stability of populations. Due to multiple risks that planktonic larvae face during the pelagic stage, benthic species with planktonic larvae may be more vulnerable to temporal variation in population genetic structure, whereas species with benthic or non-dispersive larvae are expected to be temporally more stable. We examined temporal genetic patterns in populations of a poecilogonous polychaete with within-species variation in developmental mode. Pygospio elegans can produce small free swimming larvae feeding in the plankton, or benthic larvae feeding on nurse eggs while brooded in capsules in the maternal tube. With our microsatellite analyses, we found low but significant temporal genetic differentiation in the populations with high frequency of benthic larvae. This pattern is likely to have been caused by genetic drift, since estimations of population density, Ne and migration rates among these populations were low. Stable temporal genetic structure and higher Ne was observed in the strictly planktonic population. In one population (Dutch mudflat with both larval modes), a distinct genetic turnover was detected among the temporal samples, which could have been caused by habitat change (due to harsh winter) and (re)colonization from neighboring planktonic populations. Over a long time scale, metapopulation dynamic patterns may be likely in P. elegans, especially in planktonic populations in high disturbance intertidal habitats. Because of the observed polymorphism in developmental mode seen in P. elegans, it is a good model species for research on the consequences of life history variation on population genetic patterns.