Male-to-female sex change in widowed males of the protogynous damselfish Dascyllus aruanus

Abstract

Sex change occurs in various plants and animals. Protandry, protogyny, and bidirectional (or reversed) sex change have been reported in fish. Bidirectional sex change is known in 30 species from six families, but has not been reported in damselfish (Pomacentridae). We conducted mate-removal experiments to make male/female-only groups in the protogynous humbug damselfish Dascyllus aruanus, living on branching-type corals under low-density conditions. The smaller of the widowed males on an isolated coral head changed sex to female when no females or juveniles immigrated onto the coral. Female-removal experiments are needed to verify reversed sex change in other protogynous species.