Behavioral Ecology Blog

In this post- Ill give some general background and talk about pre-copulatory sexual conflict. In the next post, Ill switch to post-mating conflict and alternative hypotheses.

Sexual conflict is defined as the conflict of interest pertaining to reproductive decisions between males and females. This problem, 1^st recognized (or at least 1^st published) by Geoff Parker in 1979, is fundamentally rooted in anisogamy, and extends through decisions related to mate choice, mating, and parental investment. Parkers initial insight was the recognition that males and females always have different motives in mind when it comes to mating. Each only has their own interest in mind, and will consider the other only in as much as this consideration enhances their own interests.. (which is usually very little) Yes, reproduction is a selfish game.

Sexual conflict can be grouped into 2 types, conflict prior to (or during) mating, and conflict after mating. The former generally has to do with the when, with who, and how many times to mate issues, while the latter has more to do with parental investment in the resulting offspring.

Conflict prior to mating

1. optimal rates

• In 2001, Gavrilets proposed genetic model of sexual conflict that showed that as a result of initial investment related to anisogamy, and its subsequent effects on the potential reproductive rates of males and females, that the optimal rate of mating would be higher (in fact, fitness forever increases as the number of mates increases) in males than in females.. Empirical evidence largely supports this conclusion. Think about humans and optimal mating rates- Once a females egg is fertilized, there is not much to gain from re-mating (except if she can fool male #2 into thinking he is the father). In contrast, males can re-mate with multiple females and potentially fertilize all of the..

• direct costs of mating

  • Energy- it takes energy to mate

  • predation- after all, who can watch out for ANYTHING during sex

  • time- you can eat/sleep/mate with others (well, maybe) during mating

  • STD’s- remember the mountain lions and koalas…

  • Bad stuff in ejaculate- OK, a cost for females only, but there is some pretty harmful stuff in semen.

• Indirect costs of mating

  • when mating with a male of low genetic quality or high parasite load (in poor health)

An additional cost incurred (usually by females) is the cost of resistance, which is at times very high. In some cases so high , that the most economical strategy is to just give in.. a simple war of attrition.