Meeting Abstract

41.3  Monday, Jan. 5  Factors Affecting the Distribution and Infection Success of Two North American Sacculinids (Rhizocephala) O’BRIEN, J.J.; University of South Alabama jobrien@jaguar1.usouthal.edu

Heterosaccus californicus parasitizes majid crabs along the western coast of North America south of Bodega Bay while Loxothylacus texanus is endemic on species of portunids in the Gulf of Mexico. For reasons incompletely understood, both species of rhizocephalans are restricted to the southern portions of host ranges. Laboratory and field studies have revealed how physical (e.g. temperature and salinity) and biological (e.g. phototaxis and host molt-stage) factors affect adult fecundity as well as the ability of larvae to disperse, locate and infect vulnerable hosts. For example, 1) brooding time of embryos is negatively correlated with temperature, which may reduce densities of infective larvae in cold water habitats; 2) L. texanus naupliar stages do not survive to the infective cypris stage in low (less than 20 ppt) water suggesting that infection occurs in lower reaches of estuaries and bays and 3) naupliar larvae of L. texanus exhibited positive phototropism which could concentrate them in surface waters during daylight hours and augment dispersion on windy days. A summary of factors possibly influencing parasite prevalence of the parasite will be presented.