Transverse ionic passages through the cuticular ductules from the haemocoel to the glandular cavities and the lumen of the spermathecal duct in female crickets (Gryllus bimaculatus)

Abstract

In the spermathecal duct of the female cricket Gryllus bimaculatus, the glandular cells, each of which has a central cavity, and the cuticular ductules, extending from the cuticular intima of the spermathecal duct, are widely distributed along the duct's length, except in the proximal and distal regions. The cuticular ductules approach the glandular cavities along a tortuous course and enter them, or run down towards them to terminate in the region of the basement membrane. When an isolated spermathecal duct was incubated in an ionic lanthanum solution, deposits of lanthanum were found in the lumina of the cuticular ductules, the secretory cavities of the glandular cells, and in the openings of the cuticular ductules to the lumen of the spermathecal duct, but also in the intercellular space, and the surface of muscle fibers surrounding the spermathecal duct. This finding suggests that each cuticular ductule is a tripartite passage between the haemocoel, the glandular cavity, and the lumen of the spermathecal duct.In many insects, the phenomenon that the secretions of the male accessory gland play various roles in the regulation or modification of the behavior and physiology of the female, has been demonstrated based on evidence provided by implantation of the accessory gland and injection of its glandular extracts into the haemocoel of the female (e.g., Leopold, '76; Gillott, '88). We have recently observed in the female cricket that the peristaltic movements of the spermathecal duct occur in response to the injection of the spermatophore contents through the copulatory papilla into the lumen of the spermathecal duct in order to facilitate sperm migration. Furthermore, the peristaltic movements of an isolated spermathecal duct can be induced by the application of the spermatophore contents to the proximal region of an isolated spermathecal duct near the genital papilla (Kimura and Yamaguchi, '87; in preparation). These observations imply that the spermatophore contents may penetrate from the lumen of the spermathecal duct to the haemocoel or the vicinity of the muscle fibers winding around the spermathecal duct which induce the peristaltic movements of the duct. However, it remains uncertain through which passage physiologically active substances delivered into the lumen of the female reproductive duct by the male during copulation reach the haemocoel. This experiment was undertaken to reveal the presence of such a passage in the spermathecal duct of the female cricket using ionic lanthanum as a tracer. MATERIALS AND METHODSVirgin and mated female crickets (Gryllus bimaculatus) were used in this experiment. The spermathecal duct was isolated together with the copulatory papilla and spermatheca. The tissues were incubated in solutions of 5 , 10, 20, and 50 mM ionic lanthanum (made from LaCl,) dissolved in physiological saline (in mM/l: NaC1, 150; KC1, 9; CaCl,, 5 ; dextrose, 40; buffered with 10 mM/1 Tris buffered to pH 7.2) at room temperature for 2 hours. The tip of the copulatory papilla was kept