AUTOTOMY IN THE BRACHYURAN, UCA PUGNAX

Abstract

Mature individuals of both sexes were tested as to the readiness with which autotomy occurred after stimulation of the legs separately. Unlike Porcellana, in which weak stimulation effected this response, very intense stimulation was here necessary. In 10 trials with the legs treated in succession, either being crushed or partially cut, [male][male] averaged 7.1 autotomized legs, non-gravid [female][female] 6.6 legs, and egg-carrying [female][female] 4.4 autotomized legs. Autotomy was decreased under conditions in which the loss of blood was greatest, e.g., when the large claw was first to be injured, when the leg was crushed on filter paper, or when cutting was done on glass. When the legs were crushed on glass, less blood was lost, and autotomy was reduced in frequency. In the 2d 5 trials with gravid [female][female] autotomy was less as compared with the other mature individuals. In successive trials a "block" gradually developed which was based upon the formation of a chemical inhibitor.