Fake sex: diploidy, dominance, coupling, attraction

Robert Ian Bowers

What can be understood of a species when we know of it only that it is sexual? Two seemingly innocuous aspects of sex are considered. In Chapter Two, the matter is diploidy and allele dominance; in Chapter Three, it is the need to couple. The effects of each of these, upon the evolution of a species, is investigated by simulating them in an arbitrary sexual species within the JAWAS agent-oriented simulation framework. The aim is to make predictions for the behaviour of organisms that evolve under these circumstances: with a diploid genome, preserving dominance relations, and under the sway of the social dilemma imposed by the need to couple. Diploidy fulfils its promise of preserving variability, whereas haploidy quickly commits its possessors to the current niche. Allele dominance too preserves variability, and without sacrificing adaptivity. These results echo consistent findings in classical population genetics. The expectation of a sex-based division of labour in coupling efforts leads to the identification of several conditions under which such asymmetries are likely to emerge. In particular, sexual selection upon variable attractants, and the presence of mood-dependent attractants are implicated as ingraining sexspecificityin attraction and sexual motivation in predictable ways. Implementations of these aspects of sex markedly affect how agents evolve. Apart from making predictions about natural sexual systems, these results lead to concerns of efficacy, and so make recommendations for how an artificial system that relies on evolution could benefit from implementing sex.