POPULATION-STRUCTURE AND GENETIC-VARIATION IN 2 TROPICAL SEA-ANEMONES(CNIDARIA, ACTINIDAE) WITH DIFFERENT REPRODUCTIVE STRATEGIES

Genetic variation and population structure of two tropical sea anemone s, Bunodosoma caussarum Correa and Actinia bermudensis McMurrich were related to their different dispersal capabilities and reproductive mod es. B. caussarum reproduces sexually and has a long-lived planktotroph ic larva; A. bermudensis can reproduce both sexually and asexually, su pposedly with short-range dispersal. Both species were sampled along 1 150 km of Brazilian coastline between 1990 and 1991 and analyzed by ho rizontal starch gel electrophoresis for 16 enzyme loci in B. caissarum and 19 in A. bermudensis. B. caissarum had higher levels of heterozyg osity (H=0.35) and lower levels of population structuring (F-ST=0.042) than A. bermudensis (H=0.17; F-ST=0.262). At one locality large genet ic differences between two sympatric colour morphs of A. bermudensis p rovide evidence of possible cryptic speciation. Overall levels of gene tic variation and heterozygosity in the two species are compatible wit h their known modes of reproduction.