Significance of feeding to the development of postlarval megalopae in the free-living crab Lophopanopeus bellus and commensal crab Fabia subquadrata

Abstract

Crab megalopae, derived from wild caught terminal stage zoeae, were reared in ‘point of no return’ (PNR) diet treatments consisting of progressively extended initial periods of starvation followed by continuous feeding and ‘point of reserve saturation’ (PRS) treatments consisting of progressively extended periods of feeding followed by continuous starvation. No unfed megalopae of either the free-living Lophopanopeus bellus or the commensal Fabia subquadrata survived to Crab I, while megalopae fed continuously on brine shrimp Artemia sp. nauplii showed high survival. Extension of initial starvation produced increased mortality and delayed molting in both species, with a PNR of 9 d in L. bellus and 8 d in F. subquadrata. Megalopae thus must initiate feeding by approximately one-half of the mean stage duration of those continuously fed. L. bellus megalopae initially fed for only one-third of the mean stage duration showed the same survival as those continuously fed, while F. subquadrata megalopae fed for only one-third of the mean stage duration showed some survival to Crab I, but required feeding for two-thirds of the mean stage duration to equal the survival of those continuously fed. Neither species showed differences in stage duration on treatments that supported development. Independence from the need to feed during the latter part of the megalopa stage may permit a more effective response to settlement cues and be beneficial to the role of the post-larva in identifying benthic settlement sites.

Breanna Harris, Ph.D.

Assistant Professor

I am a behavioral endocrinologist studying how organisms physiologically and behaviorally respond to and cope with challenges (stressors).