REITZEL, Adam M; SULLIVAN, James C.; FINNERTY, John R.; Boston University; Boston University; Boston University: Life History and Population Dynamics of a Parasitic Sea Anemone, Edwardsiella lineata

Edwardsiella lineata, a species of burrowing anemone in the Family Edwardsiidae, displays a unique life history where the larvae selectively infect then parasitize adult ctenophores from the species Mnemiopsis leidyi. Despite its commonality along the Atlantic coast of the United States and frequent implication as cause for dermatitis in beachgoers, little research has been reported on this species. Here we report on this species� life history stages, general development, infection frequency in ctenophores from southern Massachusetts, and population structure based on AFLP fingerprinting. E. lineata individuals were collected from ctenophore tissue in summer and fall 2004. Infection frequencies both in percent ctenophores infected and number of E. lineata individuals per ctenophore were variable throughout this time period. Population genetic data suggest a high degree of genetic variation. The parasitic stage, which varied in size from 2 to 10 mm, has a clearly defined oral opening and pharynx, but little additional structure. Upon excision from the host ctenophore, individuals differentiate into a typical planula larval form and swim actively for one or more week then metamorphose into juveniles with eight tentacles and eight well-defined mesenteries. We compare our results to the development, life history, and population genetics of another closely related anemone, Nematostella vectensis.