Written in response to increasingly woolly thinking about the level (species, population, group vs. individual) at which natural selection operated, and given further impetus by the publication of Wynne-Edwards’ overtly group selection selleck Animal Dispersion in Relation to Social Behaviour (1962), Williams, together with John Maynard-Smith, and David Lack spearheaded a revolution in evolutionary thinking (Parker, 2006).

An explicit focus on individual selection changed the way certain biologists thought about sexual reproduction and revitalized Darwin’s all-but-dead concept of sexual selection. Ironically, it was T. H. Huxley’s grandson Julian Huxley who had previously sounded the death-knell for sexual selection in the 1930s. Huxley (1938) accepted the existence of male–male buy FK228 competition, but viewed it as an adaptation that allowed the stronger individuals to reproduce and hence benefit the species. As for Darwin’s idea of female choice, Huxley (1938) simply dismissed it (Parker, 2006). Julian Huxley also reinforced Darwin’s view about monogamy, and based on his observations of great crested grebes Podiceps cristatus, suggested that monogamy was

the most harmonious (mating) system and one that humans should emulate (even though Huxley himself could not: Bartley, 1995). More ironically, Huxley (1912) was among the first to perform an explicit study of extra-pair behaviour in birds, but group selection thinking meant that his best interpretation of the forced extra-pair copulations he witnessed in mallards Anas platyrhynchos was that it was ‘disharmonious’. The key architects of the individual selection approach

to sexual selection were Geoff Parker at Liverpool, and Robert (Bob) Trivers, then at Harvard, and their contributions are well documented (see Segerstråle, 2000; Alcock, 2001; Birkhead & Monaghan, 2010). Parker’s approach comprised a mixture of theory and an impressive suit of empirical studies of sperm competition in yellow dungflies Scatophaga stercoraria (Parker, 1970, 2006). His paper Sperm competition and its evolutionary consequences in the insects, published in Biological Reviews in 1970, explained the evolutionary logic but medchemexpress also set out the agenda for future sperm competition studies. Trivers’ initial contribution was mainly theoretical, although in the present context, the fact that some of his ideas were inspired by earlier studies of pigeon behaviour (Whitman, 1919) and by the pigeons outside his office window is significant because it demonstrated the feasibility of exploring the behavioural aspects of sperm competition in birds (Trivers, 1972, 2002) (Fig. 2). Parker and Trivers were more than simply the architects of a revival of sexual selection; along with several others, they were also instrumental in developing the enormously successful field of behavioural ecology (e.g. Krebs & Davies, 1978; Segerstråle, 2000; Alcock, 2001).