Autotomy and Regeneration of Appendages in Crustaceans: A Review

Autotomy of appendages is a self-protection mechanism in crustaceans, which is defined as the reflexive loss of a limb in response to predation, competition, or other environmental factors. Single-limb injuries were the most common among the species surveyed in the present study, and the chelicerae were the most frequently lost appendages. After autotomy, hormones and signaling pathways are altered. Loss of limbs can affect foraging efficiency, although cheliped loss may be compensated by shifting to alternative prey or using both motor and oral appendages. In heterogeneous species, the loss of the major chelae may affect the selectivity of feeding. Autotomy can affect crustacean growth by reducing size increases at molting and altering the timing of ecdysis. In commercial production, removing chelicerae is an effective strategy to reduce cannibalism, and production of soft-shell crabs can be increased via autotomy. After autotomy, a new limb will regrow through regeneration and molting. This process involves the regulation of hormones, regrowth of nerves, and a number of signaling pathways that include the Wnt/β-catenin signaling pathway and transforming growth factor β signaling pathway. Crustaceans are somewhat different from vertebrates in terms of regeneration. This review provides theoretical guidance about autotomy and regeneration applied in artificial aquaculture, and we offer several suggestions for future research on autotomy and regeneration in crustaceans.