advantages and disadvantages of serial monogamy

We find that the interaction between two common features of eusociality – birth rates that saturate at large group sizes, and group‐size dependent helping decisions – can instead determine whether eusociality outperforms other strategies.

With realistic ecological assumptions, we show that eusociality does not face a previously postulated ‘risk‐return tradeoff’. Theories concerning the origin of eusociality in Hymenoptera have tended to focus on genetic relatedness, but ecology can be just as important. We then survey Hymenoptera with more specialised morphological castes, and show how the interaction between two common features of eusociality – saturating birth rates and group size‐dependent helping decisions – can determine whether eusociality outperforms other strategies. However, making empirically justified assumptions that (1) workers take over egg‐laying following queen death and (2) productivity increases gradually with each additional worker, we find that the risk‐return tradeoff disappears. The intuitive logic was that worker production represents an opportunity cost because it delays realising a reproductive payoff. inferred that eusociality rarely evolves because it faces a fundamental ‘risk‐return tradeoff’. (2015), we show how ecological assumptions critically affect the conclusions drawn. Theory has tended to focus on genetic relatedness, but ecology can be just as important a determinant of whether eusociality evolves. The origin of eusociality in the Hymenoptera is a question of major interest. The easy remedy is to always validate apparently insightful predictions from Hamiltonian equations with life-history appropriate genetic models. Simple kin selection paradigms, such as Hamilton's rule, can also fail to account for significant evolutionary dynamics created by factors, such as population structure, group-level effects or non-random mating patterns. Overall, the model and data from facultatively eusocial bees suggest that eusociality and sterility are more likely to originate through manipulation than by altruism, casting doubt on a mandatory role for monogamy. workers defer reproduction to queens), but if sterility results from manipulation by mothers or siblings, monogamy may have no effect or lessen the likelihood of sterility. Monogamy is facilitating if sterility is expressed altruistically (i.e.

Simulated evolution of sterility, however, finds that 'point of view' is critically important. It is proposed that the evolutionary routes to this obligate sterility must pass through a 'monogamy window', because inclusive fitness favours individuals retaining their reproductive totipotency unless they can rear full siblings. Many social Hymenoptera species have morphologically sterile worker castes.

Advantages and disadvantages of serial monogamy