Atrophy of nerve and neuropil following limb loss and regeneration in adult snapping shrimps, Alpheus heterochelis

Abstract

AbstractChanges in the nervous system were examined in adult snapping shrimps Alpheus heterochelis following the removal and regeneration of the minor or pincer cheliped. In order to compensate for differences amongst animals, the regenerated pincer side was compared to the contralat‐eral pristine major or snapper cheliped. In control shrimps with pristine pincer and snapper chelipeds, the number of axons in the nerves at the base of the ganglion on the pincer side constitute 74.4% of the number on the snapper side while the volume of the pincer neuropil constitutes 94.3% of its snapper counterpart. Following the removal of the pincer cheliped and the regeneration of a smaller one at the next molt, the number of axons in the nerves drops to 41.6% and the neuropil volume is reduced to 80.3% of its pristine snapper counterpart. This atrophy of the nerve and neuropil is further exaggerated following the removal of the pincer cheliped over four successive intermolts. On the regenerated pincer side, the number of axons drops to 8.5% and the neuropil volume to 61.4% compared to the pristine snapper side. Thus, loss of almost all of the peripheral sensory axons reduces the neuropil by about one third. The remaining two‐thirds of the neuropil volume is presumably comprised of input from central elements. © 1993 Wiley‐Liss, Inc.