Sperm Supply from the Testes to the Seminal Vesicle over Consecutive Matings in the Sweetpotato Weevil, <i>Cylas formicarius</i> (F<sub>ABRICIUS</sub>) (Coleoptera: Curculionidae)

Abstract

Abstract:The sweetpotato weevil, Cylas formicarius, stores free sperm in both the testes and the seminal vesicle, even though the primary function of the testes is sperm production. Here, it was investigated sperm storage in the testes in relation to mating frequency. In particular, it was examined the effect of the positional relationship between the testes and seminal vesicle, on sperm storage by counting the number of sperm in those organs. After mating, not only were the number of free sperm in the seminal vesicle reduced, but also was the number in the testes, suggesting that free sperm stored in the testes moved into the seminal vesicle during or immediately after mating. Since this weevil seems to not regulate the number of sperm in the seminal vesicle for ejaculation, the sperm supply system of the testes may contribute ejaculate to support consecutive, multiple matings by this weevil.

Positional Relationships among Male Reproductive Organs in Insects

“…Finally, sperm migration sometimes occurs immediately after mating. Male sweetpotato weevils Cylas formicarius (F.) can mate several times a night, and sperm migrate from the testes to the seminal vesicles immediately after mating [41,42]. This may be due to the fact that the seminal vesicles are adjacent to the testes, that spermatogenesis is active during the adult stage, and that sperm production is completed in the testes.…”