London, Sept 7 (ANI): Scientists have found that female chickens have evolved the ability to choose the father of their eggs by ejecting the sperm of unsuitable mates.
Researchers working with Swedish birds revealed that promiscuous roosters try to mate with as many females as possible to ensure that their genes are passed on.
But the hens manage to retain control of paternity by removing the genetic material of males they consider socially inferior.
Working with feral fowl in Sweden, the scientists found that many matings were forced, as the roosters are twice the size of the hens.
To cope with the unwanted attention, females have evolved the ability to remove the ejaculate of those males they consider undesirable.
"It's really important for females to have the best male sperm to fertilise her eggs so if she can't choose before copulation then having a mechanism to choose after copulation could really increase her evolutionary fitness," the BBC quoted Dr Rebecca Dean from Oxford University, who carried out the study, as saying.
Even when unforced, the females still exercised their right to choose by opting to eject the sperm of males they considered to be at the bottom of the pecking order.
With the reproductive odds stacked against them these low status roosters have fought back by developing larger ejaculates in the hope of increasing their chances of passing on their genes.
But according to Dr Dean, the shrewd females have worked out a way of dealing with this tactic as well.
"We found that hens will eject a greater proportion of the ejaculate from socially subordinate males, so she is in this way favouring the dominant males both before and after ejaculation," she stated.
The research has been published in the journal American Naturalist. (ANI)
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