Letthe plague begin ... :It's sand gnat time, and they really bite

ByChris Dixon

Saturday,March25, 2006

Edition:FINAL, Section: LOCAL & STATE, Page B1


Thesand gnat cometh.

As the springweather turns glorious, plans will be foiled by a pest more savagethan the most rabid mosquito and more dastardly than the fattesthorsefly.

Also known as thepunkies, marsh flies, sand flies, no-see-ums and biting midges, thesand gnat's scientific name is culicoides furens. In Charlestonese,this roughly translates to: pure misery.

It's hard tobelieve a beastie so tiny could make residents from I'On to Kiawahprisoners of their million-dollar marsh side homes or leave us allswatting the air in a "Beaufort Salute" and picking our noses in afutile, shameless fury. But the sand gnat is a miniscule monster outof your worst nightmares.

"Mosquitoes havea hypodermic needle," said Charleston Mosquito Control SuperintendentMartin Hyatt. "But sand gnats literally take a chunk out of you. Theyeat you."

According toHyatt, the smallest of these midges can fly through the screens onyour porch, and only the females bite. Locating victims by scent andan impressive pair of compound eyes, these she-beasts get under yourskin by way of facial weaponry.

The gnat firstinserts two machete-like blades into your skin. Then sharp teeth ripyour skin open more as the gnat spits a vile stew of chemicals intothe wound to keep your blood from clotting. She then uses astraw-like probiscus to suck up the blood. Sometimes her translucentabdomen becomes so engorged that she can barely fly.

Like the mamamosquito, the sand gnat uses blood to feed her eggs. But unlike themosquito, she'll typically cause pain to everyone she bites. Somehumans have allergic reactions to the anti-clotting chemical and canendure a lengthy agony of raised, itchy red welts.

But unlikemosquitoes, sand gnats don't carry diseases that make people sick.

While the gnatscan surely leave new Charlestonians asking what they heck they werethinking when they moved here, the little buzzbombs actually serve avital purpose in lower salt marsh ecosystems. Most active in thespring and fall, the gnats take advantage of warm weather to laycountless millions of eggs in the spartina grass.

After heavyrains, like those of the last couple of days, the eggs will drop tothe mud. Then, four or five days later, they hatch into wigglinglarva. Around 90 percent of the larva are voraciously devoured byjuvenile fish, shrimp and other marsh critters. The other 10 percentgrow up to swarm around your head and start the swat. Considering thegnat's importance as a food source, and the difficulty andenvironmental consequences that would result from spraying its vasthabitat, you're not likely to ever see a large scale eradicationeffort.

Thus, the onlysolution for most of us is either to stay indoors or lay on the Deetrepellent or Avon Skin-So-Soft. The best ratio for adults is arepellent no more than 30 percent Deet, while for children theconcentration should be no more than 10 percent. Long shirts andpants also help, and if you're making a trip to a truly bug-ladenspot, cover every inch of skin and consider a head-covering screenedhat.

Martin Hyatt saysthe bugs have made early appearances. Barring a big freeze, we'll seea nice uptick of gnats over the next couple of weeks, followed byappearances of Asian and marsh mosquitoes later in the spring. Birdtesting for mosquito-borne West Nile virus has already begun but hasfortunately revealed no new cases. Hyatt said that it's too early topredict whether there will be a Lowcountry West Nile outbreak thisyear, or exactly how bad the sand gnats will be.

"Fortunately,sand gnats won't make you sick," said Hyatt. "They just hurt."

Reach Chris Dixon at745-5855 or cdixon@postandcourier.com