Sex reversal by implantations of ethanol-treated androgenic glands of female isopods, Armadillidium vulgare (Malacostraca, crustacea).

The androgenic glands (AGs) of malacostracan crustaceans are responsible for differentiation of male sexual characteristics, and sex reversal is readily obtained by implantation of AGs in female crustaceans. In order to induce sex reversal, we implanted inactive AGs (dead cells) into young females of Armadillidium vulgare. Before implantation fresh AGs (living cells) were treated twice with 80% ethanol for 3 min and kept in crustacean physiological saline for 30 s. We refer to these AGs as ethanol-treated AGs (t-AGs). Stage 6 females were used as recipients of t-AG implantation. They received an implant of three t-AGs (3 t-AGs) three times, once each week. Testis formation in recipients was used as an indicator of the masculinized levels of female gonads. Female sexual characteristics were masculinized in proportion to the number of 3 t-AG implantations. Three implantations (total number of t-AGs, nine glands) induced development of testes, penes, and male copulatory organs in the recipient females. Furthermore, they could produce progeny. These results show that t-AG implantations are capable of inducing masculinization of female sexual characteristics. The procedure of three implantations with 3 t-AGs at stage 6 is enough to transform the sex from a genetic female into a functional male. If t-AGs are used to implant instead of fresh AGs, we can detect the effects induced by newly formed AGs of recipient females, not by implanted donor's AGs. The present method may be useful for examining the regulatory mechanism of sex differentiation of female A. vulgare.