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Scientists probe the memory of bees

bee on flower

Bees can do extraordinarily complex things with their pinsized brains, say researchers (Source: iStockphoto)


Emeritus Professor Lesley Rogers of the University of New England in Armidale, Australia and Professor Giorgio Vallortigara, of the University of Trento in Italy report their findings this week in the journal PLoS ONE.

The researchers show that bee brains are divided into two halves with different functions in a way that is reminiscent of the hemispheres of the human brain.

In their experiment, Rogers and Vallortigara trained bees to associate a pleasant sweet taste with a lemon scent and an unpleasant salty taste with a vanilla scent.

After the bees had been trained to stick out their proboscis when they smelt lemon, but not when they smelt vanilla, the researchers tested what happened to the bees' memory when one of their two antennae was out of action.

Rogers and Vallortigara coated either the left or right antenna of the bees with a latex-based substance to stop it from detecting odour.

"When we asked the bee to recall with its left antenna coated, it could recall the memory of the two scents for up to about three hours, but it wasn't as good thereafter," Rogers says.

"On the other hand, if we coated the right antenna and tested its recall, then initially it didn't do well, but after six hours it could recall."

The same pattern held true when the researchers simply held the scents to the left or right sides of the bee, rather than coating one of their antennae.

Short-term and long-term

The results of the experiment suggest that the right antenna and the associated brain structures form the basis for a short-term and relatively temporary memory, while the left antenna supports long-term learning.

Compared to humans or other large animals, bee brains are incredibly simple, Rogers says.

"Yet with that very simple brain they can do extraordinarily complex things. They can do amazing learning feats that we never thought possible before," she says.

"Obviously they're wired up very efficiently, these bee brains."

Until the mid-1970s, scientists thought only humans had brains divided into two hemispheres with different roles. Since then, however, researchers have shown that all other vertebrate animals have similar two-part structures to their brains.

And more recently, it has become clear that even insects, such as bees, have this kind of division of brain function.

"There's probably something quite essential about having the right and left sides controlling different functions and being differentially involved in memory formation," Rogers says.

Tags: beekeeping, animal-behaviour, entomology, neuroscience, invertebrates