Biologically speaking, men have no use after reproduction, and it's debatable how useful we are before that, either. Species that kill the male after sex are in fact onto something — cutting out the middleman. As a delivery system for a single gamete, we're wildly inefficient.
A new study, published in Nature, hints that we may have a purpose after all: sex makes a species more diverse and thus more resilient.
Published this past Monday, the ten-year study conducted on Tribolium flower beetles concluded that sex with males filters against “harmful genetic mutations” that help “populations … avoid extinction.” While asexual reproduction by females produced greater population numbers, they are genetically weaker and prone to dying out.
"Competition among males for reproduction provides a really important benefit, because it improves the genetic health of populations," University of East Anglia professor and lead study author Matt Gage told Reuters.
So the jock beetles driving Jeep Wranglers getting the hot cheerleader beetles was actually good for their species. Sucks to suck, nerd beetles.
Almost all species use sex to reproduce, though it's actually difficult to explain why. Ruthless beast that evolution is, it should've cut males out of the equation. According to Gage, one of sex's downsides (if there are any, amiright?) is that only half the offspring — females/daughters — can bear offspring of their own. "Why should any species waste all that effort on sons?" Gage said.
More than 50 generations of beetles were studied over about seven years. The population differences ranged from intense male competition to monogamous pairings with no male competition whatsoever.
Researchers found the populations forged by competition were "fitter" and "more resilient to extinction in the face of inbreeding" over those with little to no sexual selection. The latter population suffered in health under inbreeding and died by the tenth generation.
Clearly women don't strictly need men to propagate the species. But a species developed over countless successive generations of male sexual competition could totally kick that species' ass.