MECHANICAL USE OF CRAYFISH CHELAE

Chela mechanical function was investigated by comparing individuals of the crayfish Orconectes propinquus (Girard) with and without the mech anical use of their chelae (dactyls held closed with rubberbands or gl ue) to determine if crayfish need the mechanical function of chelae to feed, to deter predators, to survive in the field, and to copulate wi th mates. Laboratory studies showed that crayfish did not require the use of their chelae to consume algae or snails, but fewer crayfish con sumed juvenile insects when their pincers were non-functional. Male an d female crayfish with functional pincers were just as susceptible to snapping turtle predators in the laboratory and just as likely to be r ecaptured in the field as those with non-functional pincers. Laborator y mating experiments with two males and a single female showed that on ly males with the mechanical use of their chelae copulated. These resu lts indicate that O. propinquus require their chelae for mating but do not require functioning chelae to feed or to survive in the field.