Sydney, Aug 27 - Eavesdropping helps dry wood termites avoid their more aggressive kin as a mode of survival, according to scientists.

Both species eat dry wood and can co-exist in the same tree but each dry wood termite colony has just 200 members, confined to a single tree.

But colonies of the dominant wood-eating termite contain around a million members, including thousands of aggressive soldiers, and can forage upto 20 trees simultaneously.

'We already knew that chewing termites generate vibrations which they use to determine wood size and quality, so it seemed possible that one species could detect another using these vibrations,' Commonwealth Scientific and Industrial Research Organisation (CSIRO) entomologist Theo Evans, who led the study, said.