Mystery of the bee trees
Researchers have discovered that a species of giant honeybee will return to the same nesting site after two or three years migration from over hundreds of kilometres away.
"These results show that migrating A. dorsata swarms are astonishingly faithful to their nest sites," they write.
The team studied several colonies of honeybees in India over a period of three years, using the bees' geneotype to identify the colonies.
The article is accompanied by a similar study in Malaysia by another team of researchers who found exactly the same thing and note that "home-site fidelity is well known in migratory animals, but not in social insects."
Researchers are puzzled about how bees remember where to return given that worker-bees only live for a few weeks.
"It's just one of those drop jaw things in nature that we have no idea why it happens," said researcher, Ben Oldroyd of the School of Biological Sciences.
Oldroyd favours the theory that chemical signatures left by the departing swarm enable the colony to return, with the queen bee, which lives for three or four years, suspected of playing a role. It is known that bees leave volatile substances which they recognise as their own in comb.
"But even that's not the whole story since they wouldn't be able to smell the chemicals 200 kilometres away," he said. "Perhaps it's something about the physical environment that helps guide them to the general area and they can then zero in using the chemical signature."