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Wildside: When flies attack, nobody's safe

A calm summer day in the Apostle Islands on Lake Superior, northeast point on Oak Island. Photo by Dan Wilcox

Many years ago a friend and I drove from home in Ohio to Wisconsin to look at colleges. Taking advantage of the week off for college exploration in our senior year of high school, we first went to the French River in Ontario to do some fishing. We canoed into a nice lake and had a good time catching walleyes and northern pike. The last evening we were there the black flies hatched and swarmed around us biting without mercy.

I was wearing a dark knit hat that must have attracted them. We spread on military surplus bug dope with mostly DEET (N,N-Diethyl-meta-toluamide, a nasty organic solvent), but the black flies still bit like crazy.

The next morning my face was covered with bites and looked like a bag of marbles. I could barely open my eyes.

During our paddle back to the landing we saw a bear running along the shoreline and swatting at a swarm of black flies. The bear was so harassed by the flies that it dove into the water to escape them. We had sympathy for that bear.

We drove on to Wisconsin where I signed up for college and had my first semester student ID photo taken. I looked like a monster with all the black fly bites.

My student advisor at the time, G. Z. Jacoby, is a biologist specializing in aquatic macroinvertebrates. He had sympathy for us students all bit up by black flies having suffered himself studying their life history in streams.

About 30 species of black flies (family Simulidae) live in our region. They are small (about 1/16 inch long) hump-backed flies. They lay their eggs on the water surface and on aquatic vegetation. The larvae attach themselves onto the bottom of streams and rivers where they feed on particulate organic matter. They hatch out as adults mostly in the spring and early summer. Black fly females use their knife blade-like mouthparts to slash skin and drink blood. The adult males feed on nectar.

A couple weekends ago, Carol and I sailed out of Washburn on Lake Superior in our boat Sea Dragon. We enjoyed beating the on-land heat out on the big water among the Apostle Islands. We had a pleasant sail north under jib alone with a steady south wind. We anchored overnight in Raspberry Bay on the Bayfield peninsula and watched a pleasant sunset. The next morning we sailed out heading back east around Oak Island.

As we approached the West Channel, a swarm of stable flies appeared on the boat. Stable flies are kamikaze attack flies that deliver a painful bite. The wind died, the heat increased, and we motored back to Washburn at a stately 6 knots accompanied by hundreds of stable flies intent on getting a blood meal. We docked the boat in the marina, hung up a fly strip in the cabin and left for Patsy's Bar in Washburn to cool down and to recover from the sustained fly attack.

When we returned to Sea Dragon, the flies that hadn't left through the companionway were stuck to the fly strip.

Stable flies (Stomoxys calcitrans) look like small house flies. Both males and females feed on blood using their stiletto-like beak to pierce the skin. They are distributed worldwide and are serious pests to people and livestock. They are common along the shores of Lakes Superior and Michigan and on the Atlantic and Gulf Coasts in the United States.

When attacked by black flies or stable flies, it's easy to go crazy. The best thing is to cover up and avoid donating too much blood. It's somewhat satisfying to swat them but there are so many that you can't possibly make a dent in their numbers.

We love sailing on Lake Superior because of the beauty of the water and islands, the peacefulness of moving with the wind and the forced relaxation of traveling slowly. However, don't enjoy donating blood to those *#&$% flies!

Please send any comments and suggestions for this column to me at wildside@rivertowns.netr.