Firefly's Body Language Has A Distinctive Neon Accent

June 29, 1985|By Denise Salvaggio of The Sentinel Staff

The intricate nature of non-verbal communication between people has long been a favorite subject of study. Exploring the significance of everything from a tilt of the head to the curl of a toe, scientists and scholars have tried to figure out what subtle messages we send to each other by way of gestures.

But for some researchers, unlocking the secrets of human body language smacks of mere child's play. They find their real challenge in attempting to decipher codes broadcast by the type of life forms that are usually designated as ''lower'' -- the firefly (family Lampyridae), for example.

Just as people may calculate the opportune time to cross their legs to produce a certain response in whoever they're conversing with, the 1/2-inch firefly has mastered the art of sending signals to others of its own kind. As anyone who has ever taken a stroll on a summer evening knows, the firefly achieves this through a series of sporadic blinks of its luminous abdomen.

The twinkling insect's yellow-green glow is caused by a combination of oxygen and a substance called luciferin, which in turn reacts with an enzyme called luciferace. These chemical interactions take place on the underside of the insect's sixth and seventh abdominal segments.

Although all of the world's 2,000 (including Florida's 45) firefly species emit light, the only true nocturnal blinkers are found east of the Rocky Mountains. In the West, wingless female fireflies glow, while the winged male does not. Also, its name falls short of accuracy because the firefly is a beetle rather than a member of the order diptera, to which true flies belong. Each firefly species has a specific ''language'' of signals unique unto itself, a fact that is frequently exploited by predatory female firefly species. Cracking the code of their prey, these so-called femme fatale fireflies reply to a blinking male by using the proper sequence of flashes. Once the smitten male is in her clutches, the subsequent communication isn't quite what he expected, and he becomes a meal instead of a mate.

According to University of Florida entomologist Dr. James Lloyd, who has studied fireflies for more than 20 years, still more non-verbal treachery is afoot in the shrubs at night. A male firefly will inject flashes into the signal of another male to confuse the female into thinking the original suitor is from another species, thereby getting the girl for himself.

However, all such intrigue vanishes with the light of day, when the firefly reveals itself as a drab dark brown and tan insect with an extended prothorax that covers its head. It may be seen nibbling on plants, but rarely does so to a harmful extent. Despite whatever significant movements it makes while the sun shines, the firefly is eloquent only at night.

NEXT WEEK: The crane fly.

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