XIV.8.1 Intersexual competition is often a factor in a process of division of the resources invested into care for offspring
It is evolutionarily most advantageous for a member of either sex to invest the smallest possible amount of resources while simultaneously achieving of the greatest possible effect, production of the greatest number of genetically related progeny.Because it is necessary to invest a certain constant amount of effort into the production of each offspring, whether energy, material or time, it is advantageous for a member of either sex if (s)he attempts to invest as little as possible and simultaneously forces his (her) partner (it would be more exact to speak of adversary) to invest as much as possible.
In some animals, both parents are required for successful rearing of offspring (biparental care); however, in plants and a great many animals, the efforts of only one parent are sufficient for achieving the same effect (uniparental care).In uniparental care, optimal preconditions are created for an evolutionary battle to occur between males and females, the central motif of which consists in an attempt to force the sexual partner to accept the greatest portion of care for the offspring.s