Meeting Abstract
31.2 Tuesday, Jan. 5 Settlement cues and their effect on gene flow in sibling species of rocky intertidal gastropods, Littorina plena and Littorina scutulata MALISKA, M.E.*; SWALLA, B.J.; Friday Harbor Laboratories and University of Washington; Friday Harbor Laboratories and University of Washington mem24@u.washington.edu
Periwinkle snails Littorina plena and Littorina scutulata (Caenogastropoda: Littorinidae) are an excellent sibling species pair to examine if larval dispersal and larval settlement affect gene flow in marine organisms with planktonic dispersal. No ecological differentiation has been shown in these planktotrophic species and studies have shown L. plena to have less gene flow than L. scutulata. We have taken a combined approach to examine what differences there may be in the dispersal of egg capsules that hatch out swimming larvae and what cues may promote settlement and metamorphosis in these swimming larvae. We cultured larvae in concentrations of 50-200/L in still flasks. We fed the larvae daily concentrations of Isochrysis galbana and Nanochloropsis sp. at 105 cells/ml. Pilot experiments found Littorina plena and Littorina scutulata to develop into pediveligers as early as 21 days post-fertilization. We also found both species to settle more often when exposed to rocks found in the high intertidal or a high intertidal alga, Fucus sp., versus a control. Both species were also found only to metamorphose in the presence of rocks or Fucus sp. Larval durations ranged between 35-58 days in L. plena (n=9) and 35-42 days in L. scutulata (n=3).
