Small Winter Stonefly

Subject: help with this bug
Location: Oakville , Ontario , Canada
February 17, 2016 9:41 am
I saw many of these bugs in the snow , sorry this is not the best of photos , this one had blue hue on its lower body , a couple of others had a brown hue , may be male , female , they were abut one centimetre in length , never seen them before , I was close to water in the harbour
Signature: Stewart


Dear Stewart,
Congratulations on your Snowfly or Small Winter Stonefly sighting.  Small Winter Snowflies are in the family Capniidae, and the exact genus and species might be difficult to identify conclusively and according to BugGuide:  “many species are restricted to relatively small areas.”  BugGuide also indicates:  “nymphs [are found] beneath rocks and gravel on the bottom of streams and rivers; adults often seen on snow, or resting on concrete bridges over streams.”  They cannot survive in polluted conditions, so the presence of Snowflies is an indication that the water in the area is pure.  The blue coloration in your individual is quite interesting and unnatural looking, resembling a digital imaging aberration much more than it does the natural coloration of any Snowfly image we have seen.  BugGuide also has many images of Snowflies in the snow.

1 thought on “Small Winter Stonefly”

  1. I volunteer with an organization here in Michigan that focuses on water quality of the local watershed. Several times a year we monitor the stream for aquatic macro invertebrates, including a January session where we specifically search for winter stoneflies. It’s really fun and a great way to experience a part of the insect life cycle that is not normally seen. There could be an organization near you that does the same work.


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