O’BRIEN, J.J.*; BOETTCHER, A.A.; BOONE, E.; SHERMAN, T.D.: Chemical cues and vulnerable hosts: An investigation into factors affecting settlement of Loxothylacus texanus, a rhizocephalan barnacle parasitizing portunid crabs in the Gulf of Mexico

The parasitic castrator, Loxothylacus texanus, stunts the growth and inhibits reproduction of economically important portunid crabs in the Gulf of Mexico where prevalence has been reported to be higher than 50% in some localities. Data from experiments utilizing lectins and specific sugars as inhibitors indicate that mannose in/on postmolt exoskeleton plays an important role in the recognition signal used by the barnacle to identify vulnerable hosts. Enhanced settlement occurred on postmolt exoskeleton that had been treated with chloroform to remove lipids suggesting that lipids may serve to mask the recognition signal. Removal of proteins from substrates by the action of Proteinase K, on the other hand, did not affect settlement. Settlement did occur under laboratory conditions on exoskeleton from species of decapods not known to be infected by the parasite. The latter data suggest caution before using rhizocephalans as biological control agents as has been proposed by others.