Honors College Theses

Publication Date



Biology (B.S.B.)

Document Type and Release Option

Thesis (open access)

Faculty Mentor

Scott Harrison, PhD


Invasive species are a significant conservation concern given their contribution to native species decline. The barnacle, Megabalanus coccopoma, is a common invasive species in tropical and subtropical regions of both the Pacific and Atlantic oceans. Little is known about the life history and ecology of M. coccopoma, and data on reproductive biology could provide valuable insight into its propensity to establish introduced populations. Most species of barnacle (including M. coccopoma) are hermaphroditic, but self-fertilization is rare in species studied to date. A recent genetic study of introduced M. coccopoma populations in the southeastern US showed high levels of genetic variation but more homozygosity than expected. One explanation for this pattern is that self-fertilization may be induced when individuals settle where no potential mates are available. The purpose of this study is to test for self-fertilization and multiple paternity in M. coccopoma using highly variable genetic markers. Larvae were collected from the mantle cavity of mature barnacles in clusters and adults isolated from any potential mates. Multi-locus genotypes of larvae were compared with maternal genotypes to detect the presence or absence of non-maternal alleles, and to determine the number of potential sires of a brood. Data revealed that the offspring of both isolated and grouped adults had allelic contributions from at least one father, rejecting self-fertilization as the method of reproduction and providing support for mechanisms such as spermcasting and sperm competition in this population of M. coccopoma.