Martha Peterson can't wait until the first fireflies come out. Neither can most of the other residents of Allison, a tiny town of about 1,000 people in North Central Iowa.
After five summers of organized collecting, the Allison Firefly Club expects to bring in its millionth insect this year, and with it, money to help pay for the community's first swimming pool.
'We're counting the days until the fireflies start,' said Peterson, 67, in a telephone interview. She and her husband, Roger, serve as firefly brokers between the families that catch the fireflies and Sigma Chemical Co. in St Louis, Mo., which pays a penny a piece for the insects.
Last year 80 families participated, netting 294,000 insects. One mother bagged 1,100 in one night. They catch them in hedges and along the edges of corn and bean fields with nets fashioned from rounded coat hangers. Many, like Peterson and her husband, hunt every night from the end of June through the second week in August.
'When you get firefly fever, you don't want any invitations to go anyplace at night,' she said. 'You just want to go out and catch fireflies.'
Children in the third to sixth grades tend to be the most dedicated.
Families use the money to buy bicycles or radios and to go on vacation, said Peterson. This year the club plans to donate half its earnings for the pool.
Sigma has been buying fireflies from Peterson and about 500 other suppliers for 27 years. The beetle's light organ, which contains chemicals that have proved useful in research and medicine, have made fireflies a marketable product.
Sigma offers more than 20 firefly products that include bioluminescence demonstration kits, dried tails, lantern extract, and fresh or frozen fireflies.
Hospitals and universities buy the products for research and are looking into its use in diagnostic tests. The chemicals can be used to detect contamination in milk and water and to determine how much cancer is in a tissue. It's been tried as a shark repellant and in the sixties was sent into outer space as a way to test for extraterrestrial life, according to Sue Hardwick, a supervisor at Sigma.
The appeal of the firefly lies in its light-generating chemicals. The organ contains luciferin, which reacts to produce light when exposed to a substance called adenosine triphosphate (ATP). ATP is a basic source of energy for living cells. Thus luciferin can be used to detect small amounts of energy use in cells. Light is generated only in the presence of one of the firefly's enzymes, called luciferase. The company sells both the enzyme and the luciferin.
In late 1985, scientists from the University of California in San Diego reported that they had used genetic engineering to make luciferase. Marlene DeLuca, a biochemist, and Don Helinski, a biologist, had taken the genetic blueprint for the enzyme out of the firefly and made lots of copies of it. They introduced these copies into bacteria, which then turned out their own luciferase.
But so far, this synthetic enzyme has not cut into Sigma's firefly business, according to the company's technical services representatives.