By Staff
My introduction to black flies came on my first trip to northern Ontario. I was somewhere around 13, as I recall, on a fishing trip led by my buddy's uncle that pretty much turned out to be an all encompassing mission from Hades. Not the least of all the trials and tribulations was hordes of voracious black flies in quantities I'd never dreamed possible. It was before the time of readily available high DEET bug repellants so we were at their mercy and they showed none. Every day from dawn to dusk, rain or shine, they swarmed around us. They took over my world, at times so thick they dimmed the daylight. I breathed them in, I swallowed them down and I bled and itched on every exposed inch of my body from their bites. It was a constant struggle to maintain some semblance of sanity.
If you haven't had the dubious pleasure of meeting the black fly they are a tiny, gnat-like bug that at first glance you may mistake for a silent flying mosquito. However, closer inspection reveals they are much bulkier than a mosquito. They have a humped back appearance that gives them their nickname, buffalo gnat. Most are dark colored and many have white stripes on their legs. The description must be somewhat generic because there are around a thousand species worldwide. Over 65 of those species appear here in Michigan. While most of us associate black flies with the north country, in some form or another they appear from the Arctic to the tropics.
Like mosquitoes, their primary food source is nectar and plant juices. Only the females bite and this is to attain the blood meal required for ovarian development. Mosquitoes quite benignly slip a sucker straw into a pore to tap blood but the black fly is not so dainty. They chew a hole in your hide, inject anticoagulant and lap up the pooling blood. You cannot feel the bite at the time of the deed. The first inkling you've been had is when you discover a trickle of dried blood. Sometime later the swelling and itching begins. The degree of this reaction depends on the susceptibility of the individual. To some it doesn't amount to much more than a mosquito bite. Others, especially with multiple bites, puff up like a balloon and experience agonizing itching and burning. I've heard of lost or stranded people actually dying from black fly bites. When swarming by the millions black flies can and do kill animals and rarely even humans. Small animals, both pets and wild, can become weak from loss of blood. Death can occur from vast numbers of bites causing acute toxemia, meaning actually poisoned to death by the injected anticoagulant. Death can also come from anaphylactic shock, an allergic reaction causing respiratory and blood pressure problems. This is the same thing experienced by those allergic to bee stings, though it takes huge numbers of the less potent black fly bites for this to occur.
While mosquitoes are a product of pooling, stagnant water, black fly larvae must have very clean, flowing water to develop. In fact, the presence of black flies is a good indicator of a healthy stream. Until the last few decades I never saw a black fly here in southern Michigan. I first started to notice them in the 1980s. Since then they have become more and more common to where in some locals they are a nuisance. That is testimony that our streams are becoming less polluted. Black flies are only active during the day. High DEET bug repellants help to a degree but are not entirely effective. Black flies like to dine in seclusion, like under your collar, shirt and pant cuffs, behind and in your ears and in your hair. It helps to tuck your pant cuffs into your socks, cinch down your sleeve cuffs and wear a hat that covers your ears. Also hit these areas heavy with bug dope. Though it is often disputed, in my considerable experience they (and mosquitoes) are drawn to dark clothing. Wear neutral tones like medium greens, dark khaki and such. Carpe diem.