ABSTRACT
P. W. Sherman noted that present-day eusocial insects tend to have higher chromosome numbers than their non-eusocial relatives, and suggested that a reduced ability to discriminate between sibs on the basis of relatedness would favor indiscriminate altruism to all. The high point of acceptance of kin selection was probably the influential and pivotal games-theoretic paper of Trivers and Hare, which linked the evolution of eusociality with that of sex-ratios. Many aspects of the biology of forms such as ants, honey bees, and termites seem scarcely relevant to evaluating theories on the origin of eusociality, because for them there is no option open to workers for selfish behavior – the benefit/cost ratio is intrinsically extremely large. Despite the undoubtedly great heuristic importance of the concept of inclusive fitness, it has proved very difficult to enter explicitly into population genetic models, although it has figured prominently in games-theoretic approaches.
