What Cues Baby Crabs to Settle Down and Behave Like Adults?
Marine biologist Charles Epifanio and his colleagues at the University of Delaware College of Marine and Earth Studies want to know what triggers baby crabs to settle to the bay bottom, where they metamorphose into young adults. Knowing the answer could not only shed light on the basic life processes that govern certain shellfish, but also provide clues to controlling such pests as the mud crab, which preys on oysters and clams. In a series of lab experiments during the past year, Epifanio and his team introduced larval mud crabs to clean rocks and shells as well as to materials covered with the natural bacterial slime, or biofilm, that rapidly coats objects submerged in seawater. “The results were striking,” Epifanio says. “The clean materials had no effect on the larvae, but the structures covered with biofilm induced the crabs’ metamorphosis to the next stage of life.” The researchers also found that exudates from adult mud crabs as well as from a predator the blue crab induced the
