How Honeybees Find Their Way Home

A foraging honeybee may travel several kilometres from its hive in search of nectar, yet it almost always finds its way back. For decades, scientists assumed that bees relied mainly on the position of the sun. New research suggests that the picture is considerably more complicated.

In a series of experiments carried out over three summers, a team led by Dr Mirela Ostrova at the Fennwick Agricultural Research Station fitted 240 bees with tiny radio tags, each lighter than a grain of rice. The bees were caught at a feeder, carried in dark boxes to unfamiliar locations up to two kilometres away, and released. Their flights home were then followed with a portable radar unit.

The first surprise was how quickly most bees recovered. Rather than flying straight on in the direction they had been heading before capture, the majority spent between one and three minutes making looping "search flights" before setting off confidently towards the hive. Ostrova believes these loops allow the bee to scan the landscape for features it recognises.

To test this idea, the team repeated the experiment in a large field of uniform grass with no hedges, trees or buildings. Here, only 38 per cent of bees returned within an hour, compared with 81 per cent in the varied farmland around the research station. "The sun gives a bee a compass," Ostrova explains, "but a compass is not a map. For a map, the bee needs landmarks."

The study also found that experience matters. Bees that had been foraging for more than a week returned faster than younger foragers and made fewer search loops. Interestingly, the older bees also coped better on cloudy days, suggesting that they depended less on the sun than their younger sisters did.

The findings have practical implications. Across the region, many farms have removed hedgerows and isolated trees to create larger fields suited to modern machinery. If bees depend on such features to navigate, these changes could make foraging slower and more tiring, reducing the amount of food a colony can gather. Ostrova's team is now working with local farmers on a trial in which strips of flowering shrubs are planted along field edges, to see whether these help bees find their way.

Not everyone is convinced. Dr Joel Varga, an ecologist who was not involved in the study, points out that being shut in a box may itself cause stress, which could affect the bees' behaviour. He would like to see the results confirmed with bees tracked on their natural foraging trips. Ostrova accepts that this is a fair point, but notes that such tracking is technically much harder.