Vibrating hairs help bees ‘see’ electric fields

Bumblebees forage using changing electric fields in the air, but how they detect them has remained a mystery to researchers.

A new paper in the Proceedings of the National Academy of Sciences suggests the bees use tiny sensory hairs, and to a lesser extent, antennae, to sense their surroundings.

The finding may shine a light on the use of sensory hairs across other animals, according to the researchers.

Many animals use electroreception to help them hunt prey. Sharks, dolphins, platypus and echidnas all have electro-receptors in their snouts which help them forage in wet soil.

Bumblebees, on the other hand, are able to detect changes in electric fields – for example, the kind that might occur as they approach a flower – in dry air. Researchers at the University of Bristol in the UK wanted to find out how.

Led by biologist Gregory Sutton, the team monitored the impact of sensory hairs and antennae on bumblebees (Bombus terrestris) as they flew through changing electric charges, which were created artificially using lasers.

They found that the electricity caused the hairs and antennae to move “like a stiff rod, pivoting the base where mechanosensory neurone are located”, like a lever.

But the hairs were found to be more sensitive to electric fields, and to vibrate with more gusto, than the antennae.

The researchers also found that unlike antennae, sensory hair movement sends messages to the bees’ nervous system via the mechanosensory base, suggesting the hairs are a bee’s key to monitoring its surroundings.

This finding, according to the researchers, brings the “tantalising” possibility that electroreception could be widespread across the insect world, with a huge range of applications beyond just foraging.