Research team develops new understanding of egg trading by hermaphrodite animals

Friday, January 24, 2020 - Toulouse - "Egg trading", the mating behavior of simultaneously hermaphroditic animals such as the hamlet, has fascinated and puzzled biologists for decades. Using a new game theoretic model, an international and multidisciplinary team of researchers has worked out the conditions under which this mating system evolved. Their results have been published in The American Naturalist.

Simultaneous hermaphrodites concurrently own both male and female sexual organs. Although some of these animals self-fertilize, many (such as the hamlets Hypoplectrus spp. living in the Caribbean) do not, and have to mate with other individuals in order to reproduce. Since eggs are more costly to produce than sperm, individuals should generally show a preference for mating in the (cheaper) male role, rather than in the (more expensive) female one. However, for the mating to be successful, one member of the mating pair necessarily has to mate in the more costly female role.

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