Sex ratios and social evolution

Abstract

Dusing's basic insight into how sex ratios evolve has been developed into a wide-ranging and successful theory that predicts both the conventional 1:1 sex ratios and numerous extraordinary ones. A surprising amount of the evidence has come from haplodiploid Hymenopteran insects, though many of these effects can also be found in other organisms, even where chromosomal sex determination mechanisms would seem to lock them into 1:1 sex ratios. Most important, this seemingly arcane topic has played very prominent roles in the development of game theory, in the debate over group selection, in supporting kin selection and parent-offspring conflict, and in the field of within-organism conflict. Many biological advances will require high tech instrumentation and deeper probing into molecular mechanisms of model organisms. But there remains room for a good theory, for adroit choice of non-standard organisms, and even for simple counting.