Fireflies: The Twinkle in Nature's Eye

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All I know is that to this day, Hugh, Laurel and I speak in reverent tones when we recall "the Firefly Night." For us, it's one of those shared experiences that go into the glue that binds friends for good. So what if what we witnessed was only some cog in a life cycle's wheel? It was magic — the sort that makes a person just that much gladder to be alive.

And that, I think, sums up the relationship that has always existed between humans and fireflies. Never mind how and why they do what they do. We're talking about an insect that mimics the stars.

In recent years, though, scientists have learned that the firefly's biology may be as impressive as its wondrous glow.

Language of Love

There are some 2,000 species of fireflies, many of them native to the tropics in South America and the Pacific Ocean. They're all members of the family Lampyridae, which loosely translated means "shining fire." And there's not a true fly among them — with two pairs of wings rather than the fly's single pair, fireflies are beetles.

Like many other members of that clan, they depend on two stiff outer wings for armor when at rest, and in the air hold those wings out to either side as stabilizers while powering their flight with the other wings. Fireflies are bottom heavy so they fly like Tinker Bell, with their bodies nearly vertical.

In the United States there are about 150 firefly species, most residing in the East, from about central Kansas eastward. Typically in a given region a half dozen or more species share the same living space. This can cause problems, not only for people trying to study them but for the insects themselves, because most fireflies — despite variations in size and color — look a lot alike.

Scientists, in fact, remained essentially in the dark about the insects" diversity until they were enlightened by flash-pattern research in the 1940s. Different species, it turned out, could be identified by the distinctly different flashes each uses to locate mates of its own kind.

This arrangement makes a lot of sense. While groping around in the dark may work OK in your average singles bar, it's a risky technique in the predator-infested bug-eat-bug world of fireflies. So instead, each species has developed a code that allows compatible males and females to locate one another from a distance.

Generally, the males fly around flashing and searching while the females watch and wait on the ground. The codes can be extraordinarily complicated; timing, it seems, is everything. Some fireflies flash rapidly twice, then stop, repeating the code every 7.5 seconds. Others flash just once at intervals of precisely 5.3 seconds. Some flash as many as 11 times in a row. Still others use combinations of long and short flashes, like the dot-dash language of Morse code.

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