Sydney, May 31 : A team of UK and Australian ecologists says queen bees were not polygamous right from the beginning, and that they became so after ensuring that their offspring would be taken care of by the hive.
Led by behavioural ecologist Madeleine Beekman, an Associate Professor at the University of Sydney, the researchers compared the mating behaviour of 267 species of bees, wasps and ants that live together in highly co-operative societies. Writing about their findings in the journal Science, the researchers revealed that in older species, females were always monogamous, and that species with polygamous females like queen honeybees evolved relatively recently.
The researchers said that their findings added weight to the "kin selection" theory for why do some individuals of a species altruistically look after someone else's offspring?
According to this theory, helping to rear the offspring of relatives, rather than reproducing personally, is an effective way of passing on your genes.
Biologists who challenge this theory point to honeybees to show that co-operative childcare exists even when the offspring are not highly related, because they are the product of the queen mating with many males.
However, Beekman insists that honeybees evolved relatively late in the piece, and the females of species that evolved earlier were monogamous.
According to him, this supports the kin selection theory that co-operative societies evolved when the offspring were related and only then did multiple mating evolve.
"Females had to refrain from multiple mating in order for sociality to evolve," ABC Online quoted Beekman as saying.
He further said that sociality eventually gave rise to the specialised roles seen in honeybees, wherein the egg-laying queen and worker bees that care for the young are highly dependent on each other.
"Once that point had been reached in evolution, the queen could do whatever she wanted, like mate with more than one male," said Beekeman.
The researcher said that mating between the queen and a number of males led to the genetic diversity in the colony, and thereby made the colony more resistant to disease.
Another advantage it provided was that worker bees from different fathers had different strengths and weaknesses to have specialised roles in the colony, he added.