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Dryad

Data from: Functions of bidirectional sex change and simultaneously hermaphroditic phase gonads in the monogamous goby Lubricogobius exiguus

Data files

Jul 07, 2025 version files 44.37 KB

Abstract

Hermaphroditism has been widely confirmed in fish and includes four recognized types: protogyny, protandry, bidirectional sex change, and simultaneous hermaphroditism. Among these, bidirectional sex change and simultaneous hermaphroditism are considered the most flexible sexual patterns, due to their frequent switching of functional sexes. They are predicted to evolve under conditions of limited mating opportunities, such as low population density and mobility, and are thought to share common evolutionary factors. The goby Lubricogobius exiguus exhibits bidirectional sex change, with simultaneously hermaphroditic (SH) phase gonads, containing both developed testicular and ovarian tissues, particularly in females and solitary individuals. In this study, we conducted field observations to examine the mating system in L. exiguus and investigate the significance of its plastic sexual patterns. The results revealed that the goby randomly formed mating pairs, regardless of body size. Although a few pairs maintained long-term mating relationships over 70 days, approximately half of the pairs dissolved within 11 days. Under frequent partner changes in the non-size-assortative monogamy, the goby individuals rapidly established new mating pairs through bidirectional sex change using SH phase gonads. This sexual plasticity enabled L. exiguus to initiate reproduction quickly regardless of the sex of the partner, supporting the evolutionary predictions underlying bidirectional sex change and simultaneous hermaphroditism. In addition to the characteristics of the mating system, ecological traits such as being a microhabitat specialist on sandy-bottom substrates with a short lifespan may have influenced the evolution of the sexual pattern in L. exiguus.