A real whizz in house hunting biz

HOUSE-HUNTING is off most people’s agenda right now; perhaps I shouldn’t mention so painful a topic.

Honeybees, however, pay no heed to recessions. In late spring or early summer an old queen discovers that a young pretender, one of her daughters, has designs on the throne.

The monarch leaves the hive, taking up to 15,000 loyal supporters, about half the colony, with her. They settle temporarily on the branch of a tree, while they scan the property pages.

How the bees select their new abode has been an enduring mystery but now, some extraordinary research in Maine throws light on the subject.

Honeybee queens, it turns out, are constitutional monarchs, rather like the British one. Bee colonies are, in fact, democracies and the queen has no say in the choice of her new home. Their politics is discussed in Smart Swarm, an extraordinary new book by Peter Miller, senior editor at National Geographic. It gives a fascinating account of decision-making among the social insects.

Bee housing requirements are fairly exact. Tree holes are preferred, provided there is enough space in them for the colony to grow and a small entrance hole, preferably facing south. Finding a good site is a matter of life and death; the bees can’t afford to get it wrong.

During the 1940s, Karl von Frisch showed that bees returning to a colony, laden with pollen, alight on a comb and perform a ‘tail-waggle dance’. Each bee runs in a figure of eight pattern, wagging her abdomen. The length of the dance tells other bees the distance to the flowers she has visited. The angle at which the dance commences indicates the direction of her find in relation to the sun. In 1973, Von Frisch was awarded the Nobel Prize for unravelling this bee ‘language’.

Martin Lindauer, a research student of von Frish’s, noticed that some bees returned and danced, even though they were not carrying pollen. Their dances could only lead other bees astray, so what was the point of them? Lindauer came up with an ingenious explanation; the empty-handed bees, he suggested, were scouts which had been house-hunting; their waggle-dances described the show-houses they had inspected. Some bees, he noticed, were coated in dust or soot; they must have visited holes in walls and chimneys. But with hundreds of scouts returning to a swarm, each claiming to have found a suitable site, how does a colony decide which one to follow?

Lindauer chased swarms of bees to try and connect the choice of site to information the scouts had brought back but he couldn’t confirm his theory. The site selection process would remain a mystery for another 50 years.

In the late 1990s, Tom Seeley and Kirk Visscher of Cornell University began a series of experiments on Appledore Island off the coast of Maine. They placed numbered tags and coloured marks on 4,000 bees by freezing batches of the insects to render them torpid. Then five wooden boxes were located at equal distances from the colony. Four of the boxes offered the bees two-star accommodation; space and facilities were adequate but not exceptional. The fifth box, however, was a five-star property; it had everything a colony could possibly want. Cameras recorded the bees visiting each box.

In due course, scouts began arriving at the boxes. They gave their assessments of the sites by dancing back at the swarm. The more highly a scout valued a box, the more enthusiastically she danced; her routine could take half a minute or it could go on for five. Other scouts, observing the dances of returning bees, would then visit the sites which were most strongly recommended. They, in turn, made their assessments.

The 5-star box began to attract more and more supporters. When the number of bees arriving at the box at the same time reached 15, an extraordinary change occurred. The returning scouts, instead of dancing, ran through the swarm making a piping sound.

A decision had been made; the bees revved up their engines and headed for the quality box. To get 15 scouts together at a site requires about 150 supporters, a majority of the scout population. The 5-star box had been chosen by representative democracy.