In “The perils of promiscuity” (ABC News, 23 November 2011), Abbie Thomas
reports
Promiscuous birds hatch more dud chicks, according to new findings, which counter existing ideas about the evolution of promiscuity.
Dr Jane Reid and Dr Rebecca Sardell from the University of Aberdeen report in the Proceedings of the Royal Society B that when promiscuous song sparrows mate with birds other than their partner, these couplings produce worse quality offspring.
The article is a good example of what goes wrong when researchers are trapped into looking for a strictly Darwinist interpretation of animal behavior.
All kinds of explanations are offered as to why female birds are sometimes promiscuous even though that behaviour doesn’t spread their selfish genes. An underlying assumption is that it can’t just be a choice that doesn’t happen to kill them and/or all their offspring.
A sample:
“There’s always been an argument that females must gain some benefit from being promiscuous, because the risk of being found cheating is that the partner won’t care for the young as much or will desert her,” he says.
“But increasingly people aren’t finding clear support for that idea. So we’ve had to start investigating why else might females be doing this.”
Birds are supposed to “catch their mates cheating” and “punish the family”? These are birds, guys.
Better still:
Reid says her findings potentially have implications for human behaviour.
“In terms of their mating system, humans are not really so different from socially monogamous birds and other mammals. In time, it may well be that studies of these wild populations do give us some insights into the evolution of our own social (and non-social!) reproductive systems,” she says.
Earth to researchers: Promiscuous women may choose not to raise children at all, which kind of ends the comparison with birds.
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