Limb regeneration in a common South-American littoral crab Cyrtograpsus angulatus

Abstract

The intermoult period (time elapsed between two successive moults) is shortened, its variation among individuals and the size increment at moult are reduced, in juveniles of the littoral crab Cyrtograpsus angulatus when the number of regenerating limbs increases. Bud growth rates of regenerating limbs are calculated from plots of R₄ (length of third or fourth limb bud. 100/carapace width) as a function of relative time, considering that the intermoult period corresponds to 100%. Bud growth rates remain similar for crabs with a different number of limbs autotomized soon after moult. Regeneration of a second set of autotomized limbs follows autotomy if it occurs before the growing buds of a first set have a relative size R₄ < 16. Buds of contralateral limbs autotomized at different times during the moult cycle have similar final R₄ values because their growth rates are higher for limbs lost later. Buds of limbs, autotomized after part of the moult cycle has elapsed since moult, also tend to grow faster than those lost earlier. Neither the intermoult period nor the size increment at moult are modified by a second autotomy, after or before the critical R₄ value, and by the autotomy of a single limb in different moments of the moult cycle.

Keywords :

• crabs
• limb regeneration
• autotomy
• moult cycle
• South America