Rapid transition in sexual behaviors during protogynous sex change in the haremic angelfish Centropyge vroliki (Pomacanthidae)

Abstract

We conducted male-removal experiments in harems of the protogynous angelfish Centropyge vroliki on the coral reefs of Okinawa. The largest female of a harem started male role sexual behavior on the day of male removal and started to spawn with smaller females from 1–3 days after the removal. Smaller females often spawned with the sex changer, although the eggs released in the spawning events were unfertilized until the completion of the gonadal sex change (ca. 2 weeks). The largest female could completely perform male sexual behavior before the completion of the sex change. We observed that a smaller female with which the sex changer rarely spawned left the harem to perform extraharem spawning. This observation suggested that sexual behavior by the sex changer may function to secure future mates. Behavioral sex change may commonly precede the gonadal sex change in protogynous fish.