Larval release in the crab Rhithropanopeus harrisii (gould): Chemical cues from hatching eggs

Decapod crustaceans have rhythmic larval release patterns. In the case of Rhithropanopeus harrisii substances associated with hatching eggs induce ovigerous crabs to exhibit stereotypic larval release behavior involving vigorous abdomen pumping. In this study, the pumping response of ovigerous crabs was used to investigate the chemistry of the substances (pumping factor) that evoke larval release behavior. Pumping was induced by polar substances released into sea water upon egg hatching. Pumping factor was concentrated and desalted by adsorption chromatography with Amberlite XAD-7 resin. Size fractionation by cascade pressure dialysis indicated that most of the active material had a mol. wt. <500 daltons. Biological activity was destroyed by incubation of pumping factor with a non-specific protease. Amino acid analysis of hydrolyzed factor indicated that arginine comprised -50% of the amino acids. Pumping responses were elicited experimentally by abnormally high concentrations of mixtures of the two major amino acids (arginine and glycine) in the hydrolysate. These results suggest that pumping factor is a heterogeneous group of small peptides each containing arginine. © 1985 IRL Press Ltd.

Duke Scholars

Author Daniel Rittschof Marine Science and Conservation

Author Richard B. Forward Marine Science and Conservation