A new study, led by the University of New South Wales, claims that males who are focused on pursuing multiple partners usually have stunted growth and die young as they can neglect essential needs like eating.
The findings suggest that male promiscuity is not more common, despite its potential evolutionary advantages, as it's subject to natural limitations, the Journal of Evolutionary Biology reported.Lead researcher Alex Jordan said: "Perhaps it's nature's way of telling males to be more faithful to their sexual partners. We wondered why the natural world is not a more promiscuous place.
"For males, especially, mating with a high number of partners results in the greatest reproductive success, so you would think that the rule should be the more the better. "In fact, our research revealed that males pay a significant cost of promiscuity that places an upper limit on the number of sexual partners they can have throughout their lifetime."
For the study, the researchers conducted behavioural trials with tropical fish, as well as examining the lifetime costs of male reproduction, the first such study involving vertebrate animals.