Cookies on this website

We use cookies to ensure that we give you the best experience on our website. If you click 'Accept all cookies' we'll assume that you are happy to receive all cookies and you won't see this message again. If you click 'Reject all non-essential cookies' only necessary cookies providing core functionality such as security, network management, and accessibility will be enabled. Click 'Find out more' for information on how to change your cookie settings.

It is generally accepted that from a theoretical perspective, haplodiploidy should facilitate the evolution of eusociality. However, the "haplodiploidy hypothesis" rests on theoretical arguments that were made before recent advances in our empirical understanding of sex allocation and the route by which eusociality evolved. Here we show that several possible promoters of the haplodiploidy effect would have been unimportant on the route to eusociality, because they involve traits that evolved only after eusociality had become established. We then focus on two biological mechanisms that could have played a role: split sex ratios as a result of either queen virginity or queen replacement. We find that these mechanisms can lead haplodiploidy to facilitating the evolution of helping but that their importance varies from appreciable to negligible, depending on the assumptions. Furthermore, under certain conditions, haplodiploidy can even inhibit the evolution of helping. In contrast, we find that the level of promiscuity has a strong and consistently negative influence on selection for helping. Consequently, from a relatedness perspective, monogamy is likely to have been a more important driver of eusociality than the haplodiploidy effect.

Original publication




Journal article


Am Nat

Publication Date





240 - 256


Animals, Biological Evolution, Diploidy, Female, Haploidy, Hymenoptera, Male, Models, Biological, Phenotype, Reproduction, Sex Ratio, Social Behavior