ONTOGENY OF FEMALE PRIMARY SEXUAL CHARACTERS IN THE MAJID CRABS CHIONOECETES OPILIO AND HYAS COARCTATUS

Abstract

ABSTRACT To investigate the development of primary sexual characters in the family Majidae, the spermathecae, ovaries, and oviducts of juvenile female Chionoecetes opilio and Hyas coarctatus were examined, using histology, histochemistry, and electron microscopy, and compared to those of mature females. Females were divided into 3 developmental categories, with corresponding size ranges, based on anatomical criteria: immature, premature, and mature. Immature crabs were still temporally remote from the terminal molt, had white ovaries, and the spermatheca presented a thin tissule separation between the dorsal and ventral regions. No stratified glandular epithelium was present; only a columnar epithelium lined the lumen. This epithelium tested slightly positive for amine-containing substances. Premature females were temporally close to terminal molt, had orange ovaries, and retained the tissule separation between the dorsal and ventral regions of the spermatheca. In addition, they presented a stratified glandular epithelium which developed beneath the columnar epithelium lining the lumen. The latter degenerated and sloughed into the lumen as the former developed. Mature females had undergone the terminal molt, and were examined both prior to and following egg extrusion. No trace remained of the columnar epithelium which was present in the preceding two categories. In mature females which had extruded eggs, the tissule separation between dorsal and ventral regions of the spermatheca was also absent. Neutral mucopolysaccharides dominated in the secretions of the dorsal glandular epithelium of both types of mature female. These results establish the primary sexual characters in female C. opilio and H. coarctatus, and also document the sequence of aquisition of these characters.