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New research suggests that honey bees remember the scent of the flowers they visit by allocating different types of memory to their brains. Emeritus Professor Lesley Rogers of the University of New England in Armidale, Australia and Professor Giorgio Vallortigara, of the University of Trento in Italy reported their research findings in June 2008 in the journal PLoS ONE.

The researchers show that bees’ 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 either the left or right antenna was coated 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 was not as good thereafter," Rogers said. "On the other hand, if we coated the right antenna and tested its recall, then initially it did not 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.

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.

Until the mid-1970s, scientists thought that only humans had brains divided into two hemispheres with different roles. Since then researchers have shown that all other vertebrate animals have similar two-part structures to their brains. And more recently, it has become clear that insects, such as bees, have this kind of division of brain function. "There is probably something quite essential about having the right and left sides controlling different functions and being differentially involved in memory formation," Rogers says.
Source: Stephen Pincock, www.abc.net.au