Gadagkar R
Centre for Ecological Sciences, Indian Institute of Science, Bangalore.
Proc Natl Acad Sci U S A. 1991 Dec 15;88(24):10993-7. doi: 10.1073/pnas.88.24.10993.
I present a hierarchy of models that illustrate, within the framework of inclusive fitness theory, how demographic factors can predispose a species to the evolution of eusociality. Delayed reproductive maturation lowers the inclusive fitness of a solitary foundress relative to that of a worker. Variation in age at reproductive maturity makes the worker strategy more profitable to some individuals than to others and thus predicts the coexistence of single-foundress and multiple-foundress nesting associations. Delayed reproductive maturation and variation in age at reproductive maturity also select for mixed reproductive strategies so that some individuals whose reproductive maturation is expected to be delayed can first act as workers and later switch over to the role of a queen or foundress. Assured fitness returns shows how identical mortality rates can have different consequences for workers and solitary nest foundresses because a solitary foundress will have to necessarily survive for the entire duration of development of her brood, whereas a worker can hope to get proportional fitness returns for short periods of work. In concert with assured fitness returns, delayed reproductive maturation and variation in age at reproductive maturity become more powerful in selecting for worker behavior, and mixed reproductive strategies become available to a wider range of individuals. These phenomena provide a consistently more powerful selective advantage for the worker strategy than do genetic asymmetries created by haplodiploidy.
我提出了一个模型层次结构，该结构在广义适合度理论的框架内，阐释了人口统计学因素如何使一个物种易于向群居昆虫的进化方向发展。延迟的生殖成熟降低了独居雌虫相对于工虫的广义适合度。生殖成熟年龄的差异使得工虫策略对一些个体比对其他个体更有利可图，从而预测了单雌虫筑巢群体和多雌虫筑巢群体的共存。延迟的生殖成熟和生殖成熟年龄的差异还会选择混合生殖策略，以便一些预计生殖成熟会延迟的个体可以先充当工虫，然后再转变为蚁后或雌虫的角色。有保证的适合度回报表明，相同的死亡率对工虫和独居筑巢雌虫可能会产生不同的后果，因为独居雌虫必须在其后代发育的整个期间存活下来，而工虫则可以期望通过短期工作获得成比例的适合度回报。与有保证的适合度回报相结合，延迟的生殖成熟和生殖成熟年龄的差异在选择工虫行为方面变得更加强大，并且混合生殖策略可供更广泛的个体采用。这些现象为工虫策略提供了比单倍二倍体产生的遗传不对称性更强大的选择优势。
