Date: May 30, 2016
Source: KILDEN - information and
news about gender research in Norway
Blue tit females mate with more
than one male. Several possible blue tit fathers may then work together to stop
predators from attacking their young, according to new research from the
University of Bergen. Philosopher Claus Halberg believes this research challenges
established ideas about the passive female.
"In many species, such as
the blue tit, females often mate with multiple males. We've known this since
the 1990s. The question has been why. For a long time it was thought it was to
ensure that the offspring got the 'best' genes. But our studies indicate that
it may have to do with completely different reasons," says Adele Mennerat.
Mennerat is a post-doctoral
research fellow in the Department of Biology at the University of Bergen. She
also teaches at the Centre for Women's and Gender Research.
Blue tits pair off in the winter.
While only females build nests, they share the feeding task with the males when
the young are born. But if the chicks are given a DNA test, it will often show
that they have up to three or four different fathers. For the sake of
simplicity, let's call these chicks that are not the offspring of the male
feeding them, "extra-pair chicks."
"The main hypothesis has
been that the fathers of the 'extra-pair chicks' had especially good genes and
that this was why the female had mated with them. But around the year 2000,
evolutionary biologists began to doubt whether this was the main explanation.
Many researchers tried to show this was the case -- that is, there was a
difference in genetic quality between the extra fathers and the feeding father
-- but they found little evidence for this," explains Mennerat.
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