Interruption of proecdysis by autotomy of partially regenerated limbs in the land crab, Gecarcinus lateralis

In the land crab, Gecarcinus lateralis, autotomy of partially regenerated limbs before a critical stage in the premolt period results in (1) a very rapid decrease in the serum ecdysone titer, (2) a delay in the growth of partial regenerates remaining on the animal, (3) a delay in the deposition of gastroliths, and (4) a delay in cytological changes in the epidermis. Serum ecdysone titers remain low while new limb regenerates form at the sites of those removed. Ecdysone titers rise when these secondary regenerates complete basal regeneration. Premolt events, which had ceased at the time of autotomy of the partial regenerates, resume their normal patterns of development when ecdysone titers reach the level present in the serum at the time of this interruption. We propose that the effect of autotomy before a critical period is to reinitiate a normal proecdysis. The same pattern of events occurs following autotomy of partial regenerates of crabs without eyestalks, suggesting that the decrease of serum ecdysones is brought about by some mechanism other than changes in the titer of the molt inhibitory hormone.