© 1981 by The Society for Integrative and Comparative Biology
Hormonal Regulation of Female Reproductive Behavior in Fish1
Department of Zoology, University of Alberta Edmonton, Alberta T6G 2E9
SYNOPSIS. Fundamentally different mechanisms regulate female sexual behavior in the ovoviviparous guppy and the oviparous goldfish. In the female guppy, ovarian estrogen evidently synchronizes cycles of sexual receptivity with endogenous cycles of ovarian maturation and also increases female attractivity at the time of maximum receptivity by stimulating the release of a sexual pheromone. In the goldfish, it appears that prostaglandin, released from the ovary or oviduct in conjunction with ovulation and the presence of ovulated eggs, acts on the brain to stimulate spawning behavior. In contrast to the situation in the guppy, steroid treatments alone (in the absence of ovulated eggs) fail to stimulate spawning behavior in the goldfish. It isproposed that endocrine mechanisms regulating female sexual behavior in the teleosts and in other vertebrates are less related to phylogeny than to the mode of reproduction employed. In the goldfish and several other externally fertilizing teleosts, where sexual behavior involves oviposition, female sexual behavior apparently is synchronized with ovulation by mechanisms which respond to elevated plasma prostaglandin as an indicator of the presence of ovulated eggs. In internally fertilizing species (guppy, reptiles, birds, mammals), where sexual behavior andfertilization are temporally dissociated, female sexual behavior is synchronized with ovulation by mechanisms which anticipate either an imminent spontaneous ovulation, or the potential for reflex ovulation, by responding to increases in plasma estrogen associated with folliculardevelopment.