The population structures of three Hawaiian marine gastropod species

Understanding population connectivity is crucial to clarifying our understanding of marine biodiversity and its maintenance. The population connectivity patterns of most marine species are still unknown. In Hawaii, a number of studies examining population structure implicating population connectivity patterns have been conducted. However, these studies have been limited to species of economic or known ecological importance, with a focus on large-bodied species that possess a planktonic phase in their life history. This study examines the population structure of three small gastropods in Hawaii. Although all three species are less than 10 mm in size at maturity, two different life histories are represented among them. Two of the species, Peristernia chlorostoma (Fasciolariidae) and Mitrella fusiformis (Columbellidae) are non-planktonic and develop as crawl-away juveniles, and the third, Seminella virginea (Columbellidae) possesses a planktonic larval phase. In order to examine the population structure of these three species, nucleotide sequences of the mitochondrial Cytochrome Oxidase I (COI) gene were generated and analyzed. Analyses included: Fst pairwise comparisons, Analysis of Molecular Variance (AMOVA), haplotype networks, and geographic vs. genetic distance. The species Peristernia chlorostoma and Mitrella fusiformis exhibited overall patterns of highly structured populations that one would expect from species with non-planktonic larvae and limited dispersal potential [P. chlorostoma: pairwise Fst range = 0.305 to 1.000, P < 0.05; phi st = 0.89; R2 = 0.665, P < 0.001 (Figure 4)]; [M. fusiformis: pairwise Fst range = 0.385 to 1.000, P < 0.05; phist = 0.91; R2 = 0.433, P < 0.001 (Figure 5)]. However, occasional, stochastic connections have taken place between locales for both these species, with M. fusiformis exhibiting these connections more frequently. Seminella virginea, possessing a planktonic larval phase, showed very little population structure, including a high level of haplotype sharing among islands that was not exhibited by the other two 3 species. (S. virginea: pairwise Fst range = 0.063 to 0.072, P < 0.05; phist = 0.89; R 2 = n.s.). These three species exhibit differing connectivity patterns from each other, and also from previously documented connectivity patterns for marine organisms in Hawaii. This study contributes to our understanding of marine population connectivity in Hawaii, by examining connectivity patterns in low dispersal species that represent 30% of marine species world-wide.