Overwintering Until Winter is Over

This is what happens to bugs that don't find a suitable spot to spend the winter.

About this time of year, we seem to get a lot of phone calls from very surprised customers that say things like  "I can't believe I have flies in the middle of the winter! Where could they be coming from?"  That is a typical statement in which you could replace 'flies' with all sorts of things like wasps, boxelder bugs, assassin bugs, ants, elm leaf beetles, etc.  Our customer's sentiments demonstrate that not only do many people assume that in the dead of winter(no pun intended), all of the seasonally invasive pests that they associate with the outdoors are dead, but also that these pests are not indeed dead!  So let's walk through some scenarios by which you find your home inundated with insects while the weather outside is frightful.   Since we started with flies, let's continue with flies.  This will be entitled ' A Fly's Journey Home', only it's not the fly's home, it's yours.
     All through the Summer months you notice flies here and there.  House flies gather on the shady side of your home on the really hot days, bottle flies billow up from the dumpster every time you take out the trash, and they all join with the yellow jackets to help you with your weekend barbecue.  Moving into early Fall, you notice that their activity is not quite as consistent throughout the day as it has been, many of the flies you find in the morning hours are clustered together in corners of window frames or behind gutter downspouts.  They don't seem to be as active as they once were, until the warmer afternoon hours of the day.  Every time you walk into your house, it seems like they are trying harder to follow you in.  By late Fall, the nighttime temperatures are dropping into the mid 30's and you are seeing fewer and fewer flies all of the time.  Your anticipation for the first frost to come along and kill every last one of those ants, flies, wasps, boxelder bugs, earwigs, and beetles is high, right? Wrong!  The truth is that every time you noticed a change in the behavior or number of flies throughout the changing weather conditions, they were moving, not dying.  Now that statement is not absolute, in that some insects do not find warmer places to go as the weather gets colder, and the Asian lady beetle that tries to weather a 0* night on the bottom side of a picnic table is in worse shape than the above pictured Volkswagon; but it is true for many, many invasive pests.
     Early on in my pest control career I was controlling flies at a dairy farm and I learned a lot about the preferences and behavior of flies.  I once observed an extension cord that ran from an outdoor electrical outlet to a water tank where it powered the heater that kept the cows' watered thawed during freezing temperatures.  This yellow extension cord that laid on the ground was absolutely encrusted with fly feces.  Now all around me were things that I knew flies loved, milk, manure, moisture, molasses!  Why were so many flies clustering on this electrical cord?  For the same reason that the tank heater was in the water, heat.  I don't know any dazzling scientific facts to emphasize the fly's magnificent heat-seeking abilities, but I do have that extension cord covered in fly poop during the winter to prove my point.  Fact is, as the weather outside cools down during the day and then does so even more drastically during the night, all sorts of pests have the ability to detect small amounts of warmth and to move towards it's source.  A boxelder bug who spends most of it's time near your home's foundation might find good opportunities in following heat through an aged window frame or gaps in the home's siding.  Since flies can fly, they are not limited in the location of the entry points into your home, so in addition to windows, doors, and vents, they often end up behind gutters, and in the cracks of soffit and facia.  These areas can lead directly into your attic which might happen to be a very comfortable place, at least for a while.  Before I continue with part two of 'A Fly's Journey Home', let me break to give you one example of what pests are looking for in the Fall months. 
     During the course of a given Winter, let's say for example that your daytime highs are in the high 30's and your nighttime lows are in the low 20's.  Your soil temperature at a depth of 4" away from a heated structure is 28*F.  The ground is not frozen because it doesn't rain or snow in Southeast Wyoming or the Nebraska Panhandle, at least not in 2012-2013.  You approach the outside of your home's foundation and rake away the mulch to expose the soil, or you lift up a yard ornament like a whiskey barrel planter, and what do you find?  Ants, live ants!  The ants that were supposed to be killed off by that hard frost months ago.  That's because for every 1 inch of mulch or other dense ground cover that those insects can scurry into, they gain 10* of warmth.  Amazing eh?  Alright, enough of this fun-facting and back to flies in an attic.
     I once entered the attic of a rural home located about a mile from a feedlot(that's a feed facility for cattle, in case anyone from New England is reading this).  The customer complained of a Wintertime plague of flies in the window sills, dozens a day, at a time when it didn't feel 20* warm in the sunshine.  When I lifted the attic access, before I could even shine my light around, the problem was made obvious by the sound of hundreds of buzzing flies occupying the attic space.
     Since most of us don't heat our attics(at least intentionally), eventually those flies who once had a good thing going  by escaping the elements and warming themselves in your attic, realize that the attic is now too cold for comfort and they use their super heat-seeking abilities to find the next warmest spot, which happens to be the living space of your house that can be easily accessed through a number of light fixture penetrations between your attic and ceiling.  Ever wonder why you find bugs in light fixture covers?  Once in your home, the fly is warm and perhaps recently fed. Time to indulge one of the fly's other insatiable desires, ultraviolet light.  Cue the window sill and fly is  basking in the glow, literally. He or she then expends whatever remaining energy and lifespan that remains in them trying to fly through a pane of glass.  Repeat this process daily for a two week period that results in piles of dead flies and then you call Benzel Pest Control and say "I can't believe I have flies in the middle of Winter!  Where could they be coming from?"
 "Have you read my blog?" replies The People's Entomologist.
     You can cancel your DishTV and your Netflix subscription because I can tell stories this good all day long, once a week.  You are the residents of Bayard, Bridgeport, Albin, Burns, Cheyenne, Crawford, Sidney, Alliance, Wheatland, Lusk, Torrington, and Scottsbluff.  I am The People's Entomologist and I can be found where you are, and at www.BenzelPest.com.