Source: Immunogenic males: a genome-wide analysis of repro...[J Evol Biol. 2009] - PubMed Result.
"In Drosophila melanogaster, mating radically transforms female physiology and behaviour."
What kind of delta are we talking here?
* "increase in the oviposition rate"
* " reduction in female receptivity"
* "activation of the immune system"
"The fitness consequences of mating are similarly dramatic - females must mate once in order to produce fertile eggs, but additional matings have a clear negative effect."
Before you write off this post ladies, consider that we share almost 60% of our genome with those lil' critters who appear if your bananas hang around too long.
"We propose that both sexually antagonistic and natural selection have been important in the evolution of the innate immunity genes, thereby contributing to the sexual dimorphism and rapid evolution at these loci."