UF Researcher's Innovative Fence Helps Control Sand Flies

June 24, 1998

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 inevitable that some sand flies will find little patches of skin not treated with repellent and even crawl up under hair.

"Their bite is very painful," Day said. "They really can make life unbearable, sometimes."

Day says future applications of the carbon dioxide fence range from small-scale use by homeowners to large-scale use to large-scale settings such as sports fields and resorts. In the Caribbean, particularly, he says sand flies are "unbelievable," even spreading certain livestock diseases and preventing recreational use of some islands.

The system would be easy to adapt.

The fence is a lattice of PVC pipe, hung with mesh panels coated with mineral oil. The pipes carry carbon dioxide and octenol, a chemical that sand flies mistake for water buffalo breath, which they relish.

Day says the panels act as "centralized killing stations." The carbon dioxide/octenol brew draws the flies to the fence, where they get trapped in the mineral oil on the panels and die.

To evaluate how deadly the fence is, Day places traps inside the fence on the playground. The playground traps consistently have a lower sand fly count. Day also turns the fence off periodically to do bite counts, which always go up when the fence is not operating. Day said he hopes for a long-term impact on the overall sand fly population after the fence has been running for months or even years.

Sand flies infest all of coastal Florida. Day said many control strategies have been tried against sand flies, also known as no-see-ums and winged teeth, but all have failed because of the insects' complex biology.

The carbon dioxide fence grew out of a 14-year research project to develop environmentally friendly techniques of trapping sand flies. Mineral oil works beautifully because it is non-toxic and the sand flies are not strong enough to fly out of it.

"Historically, we'd treat a marsh like this one near the school with DDT, and that worked great. Later, we'd treat it with chlordane, and that worked great. The problem is DDT and chlordane stay in the muck forever, and now they're banned," Day said. "Besides, if you spray all the vegetation on the edge of the marsh with insecticide, you kill every insect that lands on that vegetation, not just sand flies.

"What we have essentially done is remove insecticide from the marsh. We bring the sand flies to the trap and catch them," Day said. "So we're not killing butterflies, fireflies, parasitic wasps or beetles or anything other than sand flies."

UF and Air Liquide, an international company that produces carbon dioxide gas, have patented the trap.

Source: Jonathan Day, 561-778-7200

University of Florida

Related Fly Articles from Brightsurf:

Why do bats fly into walls?
Bats sometimes collide with large walls even though they detect these walls with their sonar system.

Buffalo fly faces Dengue nemesis
Australian beef cattle researchers trial the use of insect-infecting bacterium Wolbachia to tackle buffalo fly, a major blood-sucking pest that costs the industry $100 million a year in treatments and lost production.

Waiter! This soup is not fly
Black Soldier Fly larvae contains more zinc and iron than lean meat and its calcium content is higher than milk.

Eye of a fly: Researchers reveal secrets of fly vision for rapid flight control
By examining how fruit flies use eye movements to enhance flight control with a staggeringly fast reaction speed -- about 30 times faster than the blink of an eye -- Penn State researchers have detailed a framework to mimic this ability in robotics.

Baby pterodactyls could fly from birth
A breakthrough discovery has found that pterodactyls, extinct flying reptiles also known as pterosaurs, had a remarkable ability -- they could fly from birth.

New insights into genetics of fly longevity
Alexey Moskalev, Ph.D., Head of the Laboratory of Molecular Radiobiology and Gerontology Institute of Biology, and co-authors from the Institute of biology of Komi Science Center of RAS, Engelgard's Institute of molecular biology, involved in the study of the aging mechanisms and longevity of model animals announce the publication of a scientific article titled: 'The Neuronal Overexpression of Gclc in Drosophila melanogaster Induces Life Extension With Longevity-Associated Transcriptomic Changes in the Thorax' in Frontiers in Genetics - a leading open science platform.

Researchers build an artificial fly brain that can tell who's who
CIFAR researchers have built a neural network that mimics the fruit fly's visual system and can distinguish and re-identify flies.

Understanding the neurological code behind how flies fly
Discoveries about the neurological processes by which flies stay steady in flight by researchers at Case Western Reserve University could help humans build more responsive drones or better-balanced robots.

Fruit fly species can learn each other's dialects
Fruit flies from different species can warn each other when parasitic wasps are near.

New insights into the inner clock of the fruit fly
Biologists around Professor Ralf Stanewsky (University of M√ľnster, Germany) have now presented new findings on the inner workings of circadian clocks in the fruit fly.

Read More: Fly News and Fly Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.