Adaptive Value of Regenerative Ability

Abstract

THE view that the distribution of regenerative ability among and within animals is not correlated with the incidence of loss or damage to their organs, and so with survival value, rests very heavily on the work of Morgan¹ on the hermit crab, Eupagurus longicarpus. He concluded that the regenerative ability of its various appendages was not correlated with their liability to loss : in particular, the last two pereiopods (thoracic walking legs) and the abdominal appendages, all of which are protected inside the host shell and are rarely lost, regenerate well. He also found that limbs regenerate not only at their autotomy plane, classically regarded as an adaptation to facilitate both escape and regeneration, but also when amputated proximally or distally to the plane. Recent work^2,3 has tended to confirm in some detail the neo-Darwinian view that regenerative ability is correlated with its utility, as measured by the incidence of natural losses. However, since considerable emphasis has again⁴ been placed on Morgan's conclusions, it seems worth re-examining his results in the light of a survey made a few years ago (August 1955) on E. bernhardus.