Bug of the Month January 2011: Small Winter Stoneflies and Definition of Infestation

Need to Identify
Location: Northeastern Pa.
December 30, 2010 6:50 pm
Mr. Bugman,
We have had an infestation of these bugs since early November. Have no clue what they are and have searched all over online but have not yet found a match. Can you please help us identify them?
Signature: desperate in Pa

Dear desperate,
You have Small Winter Stoneflies in the family Capniidae and we are really looking forward to the opportunity to educate you regarding the complexities of the web of life on our fragile planet and to hopefully nurture an appreciation of your own unique ecosystem in Northeastern Pennsylvania.  We should start with a definition of “infestation” and for that, we are turning to our Webster’s Unabridged Dictionary that accompanies our Encyclopaedia Britannica.  “1:  the act of infesting … :  Plague, annoyance  2:  something that infests:  swarm … 3:  the state of being infested esp. with metazoan parasites in or on an animal or plant body.”  The dictionary goes on to define “infest” as “1 archaic:  to attack or harass persistently :  worry, annoy  2a:  to visit persistently or in large numbers  :  overrun, haunt …  b:  to live in or on as a parasite –used esp. f metazoan parasites of animals.”  At any rate, “infestation” has a negative connotation and though you may not understand how these Small Winter Stoneflies play a part in your ecosystem, and though you may be annoyed with their presence, they do not constitute an infestation.  They will not harm you, your pets, your home or its furnishings.
According to BugGuide, the “family is distributed throughout much of North America but many species have restricted geographic ranges, and are endemic to relatively small areas.”  That means that you might have a unique species that is endangered.  The fact that there were enough individuals to spark your concern is indicative of a healthy population.  Additionally, Stoneflies have aquatic larvae that cannot survive in polluted waters.  The presence of a large quantity of adult Small Winter Stoneflies in your area is indicative of a nearby pure water supply.  A healthy population of Stoneflies are actually an indicator that there is a healthy and diverse ecosystem in your area.  This past March, we selected Winter Stoneflies as our Bug of the Month and that resulted in a request from the Xerces Society for Invertebrate Conservation.
Because we feel so strongly about the preservation of the environment as well as promoting an appreciation of the lower beasts, we are selecting your letter and images as our featured Bug of the Month for January 2011 even though Winter Stoneflies have occupied that position of distinction on our website in the past.

I so appreciate your e-mail and sharing of knowledge on these Small Winter Stoneflies.  I understand that ‘infestation’ has a negative connotation and I didn’t mean for it to come across as negative although they are “visiting persistently and in large numbers” and are often falling from the ceiling  of our basement or siding of our house onto our bodies or into our hair.  The backside of our house is literally covered in them and you can’t come in the door without a few making their way in as well.  Nonetheless, I’m very happy to learn that they are not harmful to us, our pets, or our home. We do have a seasonal creek that runs back behind our house, so I’m wondering if that is the source of “unpolluted” water they are being attracted to?
Again, thank you for your time in helping us to identify this insect and learn more about them! We’ll tread more carefully from here on out…
The Becks in Pa.

The creek sounds exactly like the habitat needed for the larvae to mature in an aquatic environment.  Stoneflies live in running water, not standing water.