Date of Award

Fall 2007

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Ocean & Earth Sciences

Program/Concentration

Oceanography

Committee Director

John R. McConaugha

Committee Member

Alexander Bochdansky

Committee Member

Richard Zimmerman

Call Number for Print

Special Collections LD4331.O35 A49 2007

Abstract

This study investigated limb regeneration in the juvenile blue crab, Callinectes sapidus, specifically the role of the coxa and pedal nerve innervation of the regenerative limb bud over time. The coxa is a leg segment that has been defined as the source of positional, cellular, and neuronal information needed for limb regeneration in brachyuran crabs. This study indicates that removal of coxae under regenerative and non-regenerative conditions did not deter limb regeneration. The coxa is not the exclusive location of limb regenerative information since limbs re-grew with normal positional and functional arrangement in 86% of crabs showing regeneration at removal sites. The coxa itself is capable of regeneration and is necessary for the eventual support of a limb.

Growth of the pedal nerve into the regenerative bud was also investigated. Buds were removed and sectioned at various stages in the regenerative process. The innervation of the pedal nerve in regenerative buds was shown to follow logarithmic growth. The pedal nerve entered the undifferentiated bud and muscle development occurred shortly after innervation. These findings agree with other studies that have suggested the nerve has an influence on cellular differentiation.

Removing coxae from crabs shortened the molt interval, or the time between molts, only for the first post-operative molt. This removal did not affect the molt increment, or percent growth, until the second post-operative molt versus controls. Energetic adjustments because of a lost regenerative signal from coxae removal sites at Molt 1 likely accounted for this delayed difference in percent growth. Full limb length was recovered within three molts only in crabs which had no coxae removed. Limb length was not recovered within the same number of molts in crabs that underwent coxae removal.

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DOI

10.25777/1hgy-zz08

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