I’ve been a boy/dude/guy/man for over half a century. Many times I’ve heard my gender dismissed as macho, chauvinistic, uncaring, insensitive and militaristic.
But never before have I been told that all males – of all species – might be biologically redundant.
“Obviously, to reproduce sexually, you need males,” Prof. Matthew Gage of the University of East Anglia in England told Yahoo Canada. “And of the eight million or so multi-cellular species on planet Earth, nearly all use sex to reproduce.”
But there’s an efficiency problem, he said.
“Half of the individuals in most species contribute almost nothing to offspring production – they don’t lay eggs or have babies or anything like that. In most of those species, males do nothing apart from supply sperm to the female for fertilization.”
Gage and his colleagues set out to unravel the riddle: why do males actually exist?
“As an evolutionary biologist, I wanted to understand why there is sexual reproduction, when there are all these theoretical reasons against why it should continue.”
A clue lay in Charles Darwin’s second big idea. The discoverer of evolution puzzled for years over a concept he called sexual selection.
“It troubled him [because] it kind of worked in the opposite direction to natural selection,” Gage explained.
“A lot of sexually selected traits – like peacock’s tails – seem to hamper the fitness for survival of the individuals that carry it.”
An extensive seven-year study ensued, studying 50 generations of beetles. The bugs were separated into population groups where females had more, less or essentially no choice in which males they could mate with.
"These beetles are promiscuous," he said.
“They turn around a generation in about a month, so we can evolve them in the lab.”
And after seven years, some very clear differences emerged – and it’s good news for guys.
“If you have no sexual selection, those populations have very low fitness, and their productivity is very low,” Gage was able to deduce.
“If you start to in-breed them, they’ll become extinct very quickly – twice as quickly as a population that has had some sexual selection in its evolutionary history.”
It turns out the peacocks that display best, and the horned quadrupeds that butt heads best, really do have the best genetic material. Gage says sexual selection works because it is an effective filter against bad genes.
“The prediction would be that if you come from a high sexual selection history, you should have purged mutation load, and should have a healthier genome. The female is choosing and the males are competing, so we’re basically using males to clean up the population’s genome. Our results show that indeed does happen.”
“That tells us that sex allows sexual selection to act,” he concluded, “which cleans the genome of a mutation load that is otherwise very hard to clean.”
Something to reflect on, gentlemen – the next time your best pickup line gets bounced in a bar.