Meeting Abstract
Ovulation in fishes occurs when eggs detach from the ovary lining and is associated with distinct behavioral and neuroendocrine changes. Despite these changes, gravid females are often grouped together independent of ovulation status. In female Astatotilapia burtoni, measures of gravidity (gonadosomatic index) correlate with affiliative behaviors and levels of circulating sex steroids. However, whether these changes are linked to ovulation, rather than gravidity, is not known. To investigate behavioral, physiological, and neural changes associated with ovulation, we collected gravid, naturally ovulated, and hormonally-induced ovulated females after interactions with a dominant male. The hormone prostaglandin F2α is commonly used to stimulate ovulation in fishes, but how closely it mimics natural ovulation remains unknown in most species. Naturally and hormonally-induced ovulated A. burtoni females performed more affiliative behaviors than gravid, non-ovulated females. Further, males court ovulated females more than non-ovulated females. Levels of circulating sex steroids (estradiol (E2) and 11-ketotestosterone (11-KT)) were higher in naturally ovulated females compared to non-ovulated females. PGF2α induced ovulation did not increase E2 and 11-KT levels, and lowered circulating levels of progestins. To understand where in the brain increased ovulation-regulated affiliative behaviors are mediated, we are using the neural activation marker pS6 to compare neural activation patterns in socially and reproductively relevant nuclei between ovulated and non-ovulated females. Together, these results provide an integrative approach towards understanding the behavioral, physiological, and neuroendocrine changes specifically associated with ovulation.
