Self-fertilization in brooding hermaphroditic Caribbean corals: Evidence from molecular markers

The occurrence of self-fertilization in natural populations of hermaphroditic marine invertebrates has seldom been documented. This is in contrast to plant systems where studies of self-fertilization dominate plant mating system literature. Randomly amplified polymorphic DNA markers were used to assess rates of natural self-fertilization in two common hermaphroditic Caribbean corals from the Florida Keys, Favia fragum and Porites astreoides. Rates of self-fertilization in the field were found to be high (34% for P. astreoides and 49% for F. fragum) indicating that selfing is an important mode of reproduction for both species. Furthermore, rates of selfing were found to be significantly heterogeneoUS among individuals for both species and between sites for P. astreoides; thus, both species exhibit a mixed mode of mating ranging from complete outcrossing to nearly complete selfing. These results suggest that corals and other marine invertebrates may provide a rich source of comparative data for testing evolutionary theories of selfing that have primarily been developed through studies of plant mating systems.