ABSTRACT:

Our knowledge of the various modes of sexual reproduction in stony corals has increased greatly during the last two decades, but is far from encompassing the wide variety of reproductive strategies exhibited by this group. Here, for the first time in stony corals, I report on sex change exhibited by two mushroom corals, Fungia repanda and Ctenactis echinata in Okinawa, Japan.

Sex change in animals has been reported as occurring from M-F (male to female i.e., protandry) and vice versa i.e., F-M (protogyny), but in a few cases also as bidirectional. While F. repanda exhibited protandry only, C. echinata revealed a repetitive mode of sex change, which greatly resembles that of dioecious plants that display labile sexuality in response to energetic and/or environmental constraints. I posit that, similar to these plants, in the studied corals sex change increases their overall fitness, reinforcing the important role of reproductive plasticity in scleractinian corals in determining their evolutionary success.