Picky eaters. The sounds termites make while munching guide their comrades to appropriate food sources.

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Chomping their way through the wood they feed on, termites tend to be loud eaters. But new research suggests that this noise may serve a practical purpose: It may help the insects decide what to eat and where to nest.

Termites, which are blind, use vibrations as a form of communication. For example, the bugs bang their heads against the hive to warn the colony of impending danger. Termites can sense these vibrations via organs on their legs and at the base of their antennae. But no one had examined whether the loud crunching at mealtime might have significance beyond simply digesting wood.

To explore this possibility, scientists from the Commonwealth Scientific and Industrial Research Organisation and the University of New South Wales in Canberra, Australia, studied eating noises in the Cryptotermes domesticus species. When the team recorded the termites eating 20mm x 20mm and 20mm x 160mm long blocks of pine, they found that munching on the short block created a sound that measured 7.2 kHz, while eating long block produced a 2.8 kHz sound. The difference in sound frequency resulted from sound slowing down as it resonated through the longer length of wood.

The team also observed that the termites strongly preferred the smaller piece of wood. Intriguingly, this short-wood preference was overridden when the insects heard audio playbacks of termites eating the longer piece of wood. This suggests that the sounds termites make while eating communicate important aspects of the meal to members of the colony, the team reports online this week in the Proceedings of the National Academy of Sciences. The team postulates that the vibration frequencies tell termites about the size of wood--helping them to stay in the right “niche food market” to avoid competition with other termite species. The sounds may also tell others in the colony to group together, which could increase reproduction rates, the researchers say.

Insect sociobiologist James Traniello of Boston University in Boston, Massachusetts, says that the research is interesting but cautions that it's too soon to make conclusions about the function of eating noise vibrations until the work is validated in the wild.

Related sites
Traniello's Web site
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