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July 1, 2005, 7:43PM WONDERS OF NATUREFireflies are summer fairiesBy GARY CLARKFor the Chronicle
Fireflies are nature's light show of summer nights, sparkling in the evening like tiny firecrackers but making no noise and causing no harm. My granddaughter even holds them in her hand. "Don't squish them," she says, "because they're little fairies with little flashlights." Her imagination may have been triggered by Tinkerbell, the firefly-like pixie in the Disney version of Peter Pan. Of course, fireflies, also called lightning bugs, are not fairies. Neither are they flies (Diptera) or bugs (Hemiptera), but are instead flying beetles (Coleoptera). They have a half-inch long body with a black head, reddish body and a section on the underside of the abdomen called the lantern that produces flashes of greenish-blue luminescence. The luminescence is a biochemical reaction triggered by neurotransmitters when oxygen mixes with two substances called luceferin and luciferase. On summer nights, the males fly a few feet above ground flashing their lights in a mating ritual to attract females that, in turn, flash their lights from perches near ground. Females lay eggs under moist soil, and the eggs hatch as larvae (worms) that feast on slugs and snails from summer to fall, making them beneficial to gardeners. The larvae, called "glow worms," live in winter beneath the soil, emerging in the spring and pupating in early summer — finally emerging a few weeks later as fireflies. The firefly's light is not hot and causes no harm to people. The little beetle neither stings nor bites. James Russell Lowell wasn't just being poetic when he wrote, "The fireflies o'er the meadow / In pulses come and go." Fireflies can be seen in moist, wet woodlands or meadows from dusk to midnight. Houston lawyer Donald Burger posts sightings of fireflies from all over the country on his Web site at www.burger.com/firefly.htm. Burger notes that White Oak Bayou in Houston is a prime location for fireflies this summer. My granddaughter invariably finds them in nearby state parks, and I usually see them on my evening walks in our wooded neighborhood. But I don't see as many as I did when I was a boy. The twinkling beetles are declining, due in part to overuse of lawn chemicals and pesticides. Mike Quinn, entomologist for the Texas Parks and Wildlife Department, says if you want fireflies, you (and your neighbors) shouldn't use chemicals on your lawn. Gary Clark is a dean at North Harris College. Contact him at wondersofnature.
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