in pregnancy as well as feeding the child (Female fruit flies investment comes in the form of producing eggs). Whereas a male increases his chances of passing on his genes with each female he mates with, due to his relatively small parental investment. Because male success is determined by the amount of access he has to females, males must compete for access to females much more than females must compete for access to males. This competition, according to the theory, makes the “winners win bigger, and the losers…more likely to be total losers.”In their discussion of parental investment Daly and Wilson specify three different types of division. Larger females and smaller males characterize the first category called polyandry. In polyandrous species we see males making the larger parental investment, females being more combative, and males tending to out live their female counterparts. The second category is known as a monogamous breeding system. In this system the male and female parental investments are identical, the number of offspring each sex can have is identical and the fitness variances are equal. In monogamous species the male and female tend to be indistinguishable in that they are often the same size and carry the same markings. Monogamous species also have nearly the life expectancy. The final category is known as polygamy. Polygamy is a system in which the female makes the biggest parental investment. In polygamous species the male is often larger and more combative than the female and tends to live a shorter life. According to Daly and Wilson humans best fit into this last group. According to Daly and Wilson humans “are the products of a mild but sustained polygynous competition.”The Evolution of DesireIn his book The Evolution of Desire, David M. Buss submits a unified theory of human mating. He does this primarily through explaining how humans have evolved specific traits that ...
