Head-Banging Termites Caught on Film

Nov. 30, 2006 — Termites are known to send underground SOS signals to each other by banging their heads against tunnel walls, and now scientists have filmed them in the act.

The high-speed video, which captured the frantic behavior at 10,000 frames per second, reveals that some termite species are faster head bangers than others.

With each hit, the Formosan subterranean termite raises its head about 1 millimeter off the ground before slamming it into tunnel walls at a rate of about 100-200 millimeters per second. A termite native to New Orleans is even faster, with head bangs at around 400 millimeters per second. Their heads bounce and rebound off the walls like a rhythmic drum roll.

The researchers suggest the rattling noise — audible sometimes even to people — could help locate infestations.

"If a house is very infested with termites, you might be able to hear them head-banging (without special equipment), especially if you removed an infested board or crushed their galleries or part of their carton nest," said Tom Fink, who will present his findings on the head-banging behavior Saturday at the Acoustical Society of America Meeting in Honolulu, Hawaii.

Fink, a scientist at the National Center for Physical Acoustics at the University of Mississippi, explained to Discovery News that sound cues are very important to the blind insects. They're also fragile when above ground, since they can rapidly dry out and die, so maintenance of their subterranean tunnels is critical to their survival.

Head banging is like a trumpet sounded by worker or soldier termites to bring in the cavalry.

"Formosan subterranean termites will readily come to a breach (after heeding the head bang call), and you may see many if you break a tunnel," Fink said.

He speculates that termites detect the warning bangs by picking up vibrations through their legs, which have a sensory organ. The process seems to involve a trance-like "dance," whereby soldiers on duty rapidly sway forward and backward without moving their legs when they detect head banging.

To follow up to his findings, Fink tested whether listening for the pests was more effective than looking for them.

He placed vibration accelerometers — sensitive instruments designed to convert noise to electrical signals — at the base of 1,957 trees in New Orleans City Park, which is so plagued by termites that researchers can hear the insects, even without equipment, above the intense urban noise.

The listening method identified all but 3 percent of infested trees, while visual methods missed more than half.

Steve Heydon, curator and collections manager of the Bohart Museum of Entomology at the University of California at Davis, heard termite head banging, which he likened to "rattling" and "soft thumping," when he walked through grasslands in the African Congo last April.

"Termites don't really have ears, so they can't yell at each other," Heydon told Discovery News. "They also can't communicate by scent very well, but everybody is standing on the substrate, so even through walls they can communicate with vibrations."

He added, "It's as though they're living in an apartment with flimsy walls, and they bang on the walls every so often to get each other's attention."