We need a new theory of mating systems … [one] that incorporates the conflicting interests of males and females, and the factors determining which sex is in control, in order to predict patterns of male-female pairing.Gross, 1994
Given that females, to one extent or another, subvert male interests by the internal manipulation of ejaculate, it is not inconceivable that males will have evolved little openers, snippers, levers and syringes that put sperm in the places females have evolved (‘intended’) for sperm with priority usage - collectively a veritable Swiss Army Knife of gadgetry!Lloyd, 1979
The male–female interaction is an asymmetrical, usually obligate mutualism in which there are conflicts of interest whenever multiple potential partners that vary in quality are available for either sex. Understanding male–female confluences and conflicts of interest is required to explain the sexual sequence and how it evolves. Mating interactions involve multiple steps or stages, distinguishable because of differences arising out of changes in selection that occur during the sequence. Sexual selection and competition take several different forms, which must be understood before accurate interpretations can be made of mating events in any particular case.
Sexual selection guided primarily by male–female conflicts of interest can result in resolvable evolutionary chases that lead to evolutionary stable strategies but perhaps more frequently lead to chases that tend to be unending (Parker 1979).