Male intrasexual competition

In ethology, male-male intrasexual competition occurs when two males of the same species compete for the opportunity to mate with a female.

Sexually dimorphic traits, size, sex ratio,[1] and the social situation[2] may all play a role in the effects male-male competition has on the reproductive success of a male and the mate choice of a female.

For instance, in the fly Dryomyza anilis, size shows the strongest correlation to the outcome of male-male conflicts over resources like territory and females.

[1] When there is a high density of males present in the population, competition tends to be less aggressive and therefore sneak tactics and disruptions techniques are more often employed.

Male-male competition can pose many risks to a male's fitness, such as high energy expenditure, physical injury, lower sperm quality and lost paternity.

[1] An increase in male-male competition can affect a female's ability to select the best mates, and therefore decrease the likelihood of successful reproduction.