ABSTRACT: Cues associated with biofilms from the adult habitat previously have been found to accelerate metamorphosis in the megalopae of the common mud crab Panopeus herbstii (Milne-Edwards). In this study, we investigated several properties of this biofilm and further investigated the response of megalopae to exudates from adult P. herbstii. Results showed the cue to be water-soluble and suggest that it is associated with the bacterial component of the film. Biofilms from a rocky intertidal area produced a response, while films from an intertidal sand flat did not. When biofilm was allowed to form on clean glass slides in adult habitat, megalopae showed a stronger response to 10-d-old biofilms than to 2-d-old biofilms. Exudates from adult P. herbstii produced a strong response while exudates from prey species Crassostrea virginica and a closely related mud crab Dyspanopeus sayi produced a weaker, but significant response. Exudates from fiddler crabs Uca pugnax did not elicit a response. Results from these experiments suggest that there are multiple water-soluble cues that induce metamorphosis of mud crab megalopae.

KEY WORDS: Mud crab · Megalopae · Metamorphosis · Biofilm · Exudate

Published in MEPS Vol. 195 (2000) on March 31
ISSN: 0171-8630. Copyright © Inter-Research, Oldendorf/Luhe, 2000