Black Flies?

     A common question we hear in the outfitting business is, "How are the bugs?"  My sarcastic, snappy side likes to say, "We don’t charge extra for them."  Or if a person asks, "When’s a good time to come when there aren’t any bugs."  I like to answer, "We usually don’t have many in the winter."  Seriously though, the bugs aren’t that bad.  I’ve been many places and have seen lots of different bugs and if you’re outside, you’re probably going to encounter them.

     When you’re out canoe camping in the wilderness you are bound to experience more bugs than when you’re locked up in your house in the city.  Mosquitos can be ferocious on wet portages or at dusk and dawn but generally speaking they are nothing like the mosquitos I found in the Everglades.  A little bit of repellant and alot of common sense can keep a person relatively bite free.  There are other bugs too; biting flies, horse flies and black flies to name a few.  I’m not sure I know the difference between all of these species and fly bites don’t normally affect me much.  They have the tendency to make my daughter swell up and some people bleed from where they have been bitten. I found this interesting information on a website  about black flies in Maine but I thought I would share it with all of you.

When is "Black Fly Season"?
There is actually no single, uniform "black fly season."  The maps in the Maine Nature News archive are based on scattered local observations. But, there is enough information there to draw some tentative general conclusions for some locations in Maine.

Do the black flies persist after July? What is the best time to camp and hike in Maine and avoid the flies?
You have asked a very good question.  The season can begin no sooner that late April in Maine because the black fly larvae, which hatch in clear running streams, do not hatch until everything thaws and the water temperature has also risen a bit. The black fly season moves, in general, from South to North and simultaneously from the coastal plain to inland areas and from lowest elevations up to the highest. So there is no precise "end" to black fly season in Maine. However by mid-July in most places after the birds have start gobbling them up, and after the black fly adults have bred for the season and go into "dormancy", the numbers dwindle drastically almost everywhere. 
  Here are some more key pieces of information, as a further general answer to your question:

  • Black flies breed in running water, unlike mosquitoes, which breed in still water. Because there are about forty species, not all flourish at the same time.
  • Black flies can travel several miles from their breeding site, so those environmental rules cannot be counted on completely, as a means to avoid them.
  • Strong breezes tend to disperse them, as they are a very small insect.
  • I have found, and others confirm, that black flies are generally inactive until the air temperature has risen to at least 50 degrees F., even in black fly season.
  • I have also found that they seem less numerous at higher altitudes, probably because of a combination of the above three factors: the lack of expansive breeding sites, cooler temperatures and the more consistent presence of breezes.
  • "Black flies are strongly influenced by color — they find dark hues more attractive than pale ones, and blue, purple, brown, and black more attractive than white or yellow. A light-colored shirt, therefore, is a much better choice of clothing than a dark blue one. It is a moot point, however, whether blue jeans might not be better than pale trousers: if they are carefully tucked in at the ankles and are without holes, jeans may help to attract the flies away from the head region.":  Courtesy Rocco Moschetti, IPM of Alaska. 1
  • "Black flies often swarm around a person’s head because they are attracted to carbon dioxide in the breath. … Bites are concentrated on exposed areas of skin, especially along the hairline, feet, ankles and arms." Courtesy Jeffrey Hahn, University of Minnesota Extension Service. 2
  • "The bites can produce a variety of reactions ranging from little or no irritation to considerable irritation and swelling. Sensitivity varies from person to person." Courtesy Jeffrey Hahn, University of Minnesota Extension Service. 2
  • In general, unlike mosquitoes, they will not come indoors, nor fly at night, nor penetrate most clothing.
  • Local variation is the rule. Local people are usually the most helpful resource, as they observe these things very carefully.

I’m trying to get hold of pest control operator (PCO’s) or university/government experts who treat farm or indoor accounts that are bugged by this bug. Do you know of PCO’s who treat hotels, resorts, lodges, factories, homes, barns, etc.? Or perhaps you can steer me towards a dos-and-don’ts-type check list for preventing, discouraging, or treating black flies? Are there PCO’s who are involved on government committees for area-wide black fly control efforts?  Any help you can provide is appreciated.
A few pieces of information bear on your question, at least as it applies to Maine:

    • According to the Eastern Cereal and Oil Seed Research Centre (Ottawa, Canada)
      • "Unlike mosquitoes, black flies seldom attack indoors or even in in a vehicle; once they sense being trapped their attention seems permanently diverted to escape and they spend the rest of their lives crawling up the screen or window pane."
        (Note:  For the context of this quote, please go to their
        web site.)
    • Black flies breed in running water, unlike mosquitoes, which breed in stagnant water. Although there are some studies about black fly larva control, there are logistical and environmental concerns:
      • a)   Most public water supplies originate in streams and other running water bodies.
        b)   Larvae locate in very localized clusters, in dispersed, inconspicuous locations, making pesticide application much less cost effective than for other insects.
    • Black fly appearance is characterized by a succession of flourishings of as many as 20 or 30 species in a locality, each with their own breeding time and cycle (some twice a season) complicating the management of any attempted control measures.

    • Why are they called black flies when bigger houseflies
      are also ‘black’?
          Almost every animal and plant has a scientific name and a common name or names. The scientific name is universally used by scientists and students worldwide.  The common names are used in daily life and may vary from one place to another for the same animal or plant.  The group of true flies includes: house flies, deer flies, horse flies, black flies and many other species.  The scientific name that the insect family of all black flies share is Simuliidae.  However this insect has many common names such as:  black fly, blackfly, buffalo gnat, and reed smut.  In French-speaking Canada they are known as mouches noires, in Latin America as jejenes, and so forth.
          To the European explorers who first came to the Western Hemisphere black flies were almost unknown in their home countries. When they encountered them here they gave them various names, usually by comparing with insects already known.  According to Roger W. Crosskey’s book The Natural History of Blackflies (Chichester, UK: John Wiley & Sons, 1990) the name was first used in New England, by at least the late 1700’s.  The earliest non-Native persons to encounter them were merely describing the "new" insects in terms of the known insect group "flies" and the fact that they are dark-colored and that they are a type of fly.   Thus the name "black fly" came into common use, as there was no commonly used alternative.