SPERMIOLYTIC ACTIVITY OF THE EPITHELIUM OF THE SPERMATHECAL DUCT OF RHACOCLEIS-ANNULATA FIEBER (ORTHOPTERA, TETTIGONIIDAE)

This study reports, for the first time, lytic activity in the distal a nd median regions of the spermathecal duct of Rhacocleis annulata Fieb er (Orthoptera:Tettigoniidae). Lysis is more pronounced in recently ma ted females, and appears to take place in a progressive sequence origi nating in the cells underlying the cuticular intima. These cells exhib it large heterogeneous vesicles resembling lysosomes, which would part icipate in the partial dismantling of the cuticular intima. Consequent ly, the sperm found in the lumen of the latter organ penetrate the cel ls, probably pushed by the pressure exerted on the luminal walls, and then, together with the cells themselves, undergo lysis. Degradation o f spermatozoa seems to follow a strict sequence of events, which ends with the dismantling of the microtubules of the axoneme, as reported p reviously for Locusta (Cantacuzene, 1971) and for some pulmonate gastr opods (Bayne, 1970). We propose that lysis is part of the mechanism de aling with capture and subsequent elimination of surplus sperm transfe rred to the female during copulation. Accordingly, fertilization activ ity would occur exclusively within the seminal receptacle. No evidence of a similar phenomenon in the latter organ has previously been repor ted for Rhacocleis annulata. Copyright (C) 1996 Elsevier Science Ltd.