Head-banging is usually a sign of frustration in humans, resulting in little more than pain. But, for termites, head-banging serves a much more important purpose: long-distance warning of danger nearby, new research shows.
The new study, published today in the Journal of Experimental Biology, found that when danger lurks near a colony some termites start banging their heads to the ground. The signal emitted is then re-transmitted by nearby termites, effectively sending the warning message several meters away. The behavior is the first known example of non-human -distance communication.
Dr. Wolfgang Kirchner and Dr. Felix Hager, from the University of Bochum, in Germany, studied large colonies of the African termite, Macrotermes natalensis. Their research focused on the way termites navigate from their large mounds to find food outside, sometimes venturing as far as 10 meters away. On such distant wanderings, termites are accompanied by a special type of "soldier" termite, presumably for protection from predators, especially anteaters. But, to their surprise, these soldiers played another role.
Using high-speed cameras and sound capturing devices, researchers observed soldier termites rapidly banging their heads on the ground in the presence of anteaters. The soldiers would bang their heads about 11 times a second, sending vibration signals through the ground that other termites picked up and relayed back and forth between other termites. Using standard sound generators, researchers found that similar signals by themselves could not be heard more than 40 centimeters away, but teamwork made the difference. Only the social transmission of the head-drumming signal would get to every termite, even to those several meters away.
Other species of wood-boring termites have been known to use vibrations to determine the size of wood, while still others can interpret chemical signals left as a trail behind other termites. But this study is the first to show organized long-distance communication by a non-human species.
For more, read the article at: http://jeb.biologists.org/content/216/17/3249.abstract.