The American Naturalist
Throughout the great class of insects the males almost always emerge from the pupal state before the other sex, so that they generally swarm before any females can be seen. The cause of this difference between the males and females in their periods . . . of maturity is sufficiently obvious. Those males ... which in the spring were first ready to breed ... would leave the largest number of off spring: and these would tend to inherit similar instincts and constitutions. [Darwin (1871, p . 260)).
Bulmer, M. G., "The Significance of Protandry in Social Hymenoptera" (1983). Bu. Paper 6.
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