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Published February 1983 | public
Journal Article

Effects of Gamma-Aminobutyric Acid on the Settlement of Larvae of the Black Chiton Katharina tunicata

Abstract

Laboratory-cultured larvae of the black chiton Katharina tunicata (Wood), collected from central California in May and June of 1979 and 1980, settled preferentially on the encrusting coralline alga Lithothamnium sp. Metamorphosis, which involves the loss of the prototrochal ciliary band, occurred within a period of 2.5 h after larvae began crawling upon the alga. In response to gamma-aminobutyric acid (GABA) at a concentration of 10^(-6) M, the lecithotrophic trochophore larvae ceased swimming and settled rapidly. Developmental metamorphosis did not follow settlement in the absence of encrusting coralline alga. However, when both GABA and Lithothamnium sp. were present, larval metamorphosis occurred within 2 h of settlement. Significantly different rates of settlement exist for sibling larvae of different ages; 12 d-old larvae responded more rapidly and in greater numbers to treatment with GABA than 10 d-old larvae. Differences in settling rates are attributed to the onset of metamorphic competence.

Additional Information

© 1983 Springer-Verlag. Date of final manuscript acceptance: October 26, 1982. Special thanks are due to J. S. Pearse for his continued guidance throughout this study, as well as for his thoughtful criticism of the manuscript. J. West and T. DeCew of the University of California at Berkeley helped with the algal identifications, and appreciation is expressed to C. Tarp, V. Chow, D. Eernissee, C. Chaffee, and an anonymous reviewer for their many helpful suggestions. We would also like to thank W. Doyle, Director of Center for Coastal Marine Studies and Joseph M. Long Marine Laboratory, for generously providing facilities in support of this study. Communicated by N. D. Holland, La Jolla.

Additional details

Created:
August 19, 2023
Modified:
October 20, 2023