RECOVERY OF CLAW SIZE AND FUNCTION FOLLOWING AUTOTOMY IN CANCER PRODUCTUS (DECAPODA, BRACHYURA)

We examined recovery of claw size and function following autotomy in r ed rock crabs Cancer productus. We also tested for costs of regenerati on to growth and documented the frequency of claw injury in C. product us populations in Barkley Sound, Canada. Field and laboratory results indicated that crabs required at least three molts to recover a full-l ength cheliped. For injured crabs, regenerating claws were significant ly less powerful than contralateral, normal(i.e., uninjured) claws eve n two instars after autotomy. Greater mechanical advantage in normal c laws of injured (vel-sus uninjured) crabs, however, suggests some morp hological response by the remaining normal claw to increased exercise. Despite this compensatory response, our experiments indicate that inj ured crabs remain at a significant disadvantage while foraging. After adjusting for differences in propodus length, both regenerating and no rmal claws of injured crabs delivered significantly lower crushing for ces than did claws of intact crabs. Energetic costs, in the form of re duced body size increase at the molt, were detected only for crabs reg enerating both claws. High incidences of single claw loss in C. produc tus in Barkley Sound, together with our experimental data, suggest tha t much of the population experiences a prolonged foraging handicap fol lowing injury.