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How to test a bee's sense of smell

3 October 2013 Last updated at 14:00 BST

Scientists in Southampton have discovered that honeybees' ability to find flowers could be hampered by a chemical in diesel exhaust.

A chemical called NOx, present in diesel exhaust, affected the insects' response to these scents.

The researchers used a sort of bee "sniff test", known as the proboscis extension reflex test, to see how sensitive the bees were to floral scents.

This footage, of a version of this experiment being carried out by scientists at the University of California San Diego, shows how the experiment works. The bees are given a drop of sugary liquid and respond by sticking out their tongues.

By pairing the sugary reward with a particular smell, the bees can be trained (or conditioned) to respond to a particular scent by sticking out their tongues.

Footage courtesy of Daren Eiri