Meeting Abstract

62.1  Wednesday, Jan. 6  Effects of selfing on offspring survival in the marine bryozoan Bugula stolonifera JOHNSON, C.H.; Harvard University

Although the reproductive biology of bryozoans is widely studied, investigations examining the occurrence and consequences of selfing in these simultaneous hermaphroditic colonial invertebrates are sparse, and the results are contradictory. Over the past two summers, experiments were conducted examining the effects of selfing in the marine bryozoan Bugula stolonifera. Larvae from field-collected colonies were cultured through metamorphosis to reproductively mature colonies either in isolation, or in the presence of other colonies (multi condition). In summer 2008, results demonstrated that colonies reared in isolation produced viable larvae that successfully completed metamorphosis, thus documenting that selfing is possible in this species. Larvae from colonies reared in isolation, however, experienced significantly decreased viability compared to those in the mutli condition. Larvae from the isolated condition had both decreased rates of successful metamorphic initiation and completion. These experiments were extended in summer 2009, whereby metamorphs from colonies reared in the isolated and multi conditions were transferred back to the field. These individuals were routinely monitored and were returned to the laboratory 21 days after onset of reproduction. These experiments revealed additional deleterious effects associated with selfing, as no viable larvae were recovered from colonies deriving from the isolated conditions. In contrast, offspring from the multi condition released 1030 larvae, 98.8% initiated metamorphosis, 96.5% of which completed metamorphosis. Overall, these results demonstrated deleterious effects associated with selfing in B. stolonifera. Selfed larvae not only had significantly decreased chances of survival, but those that did survive had a low probability of successfully reproducing.