BOYNTON BEACH, Fla.--When the children at St. Mark Catholic School hit the playground, the biting sand flies in the mangrove marsh next door start smacking their little bloodsucking lips.
Like all their biting kin--mosquitoes, deer flies, horseflies and black flies--sand flies use carbon dioxide to locate a host. So the huffing, puffing children on the playground present a smorgasbord, said University of Florida researcher Jonathan Day.
"They are all beacons out there, flashing 'blood meal, blood meal, blood meal,'" said Day, an entomologist with UF's Institute of Food and Agricultural Sciences.
But Day hopes to use the sand flies' thirst for blood against them. Between the marsh and the playground he has built a fence that seeps carbon dioxide. By simulating a human presence, the carbon dioxide tricks the sand flies into making a detour and lures them into traps along the fence line. The date with dinner becomes a date with death.
The carbon dioxide fence at the school is the first field demonstration of Day's system. A test of a similar fence at UF's Florida Medical Entomology Laboratory in Vero Beach caught 200,000 sand flies per night. Already, he said, the real-world test looks promising, and parents of students at St. Mark agree.
"My kids would come home with terrible bites all over their bodies, almost as bad as chicken pox," said Carol DeCanio, whose son and daughter attend the school. "It was very difficult sending the kids to school knowing they would come home with these bites."
Since Day turned the fence on in April, however, her son Michael says things have gotten better.
"It used to itch so much I couldn't stop itching," Michael said. "This helps because in the middle of class you're not itching anymore. You're doing your work instead of scratching your bites."
Repellents provide limited relief because sand flies are so persistent, Day
said. With populations in the millions near swampy areas, it is inevit
Contact: Jonathan Day
University of Florida