Swarming Caddisflies, we believe

Location: Davenport, Iowa
June 14, 2011 3:12 pm
Please help me identify these insects. They swarm to the security light outside of the house by the thousands. They make their way into the home and vehicles parked outside. I sprayed an insecticide directly into a cloud of these bugs on our home. They fell to the ground and within seconds, there were just as many swarming the light again. They also seem to die on their own because they literally carpet a portion of a walkway every morning. It has been happening nightly since about June 10th. It was suggested these are Mayflies however they do not resemble the photos I’ve seen online.They seem to be mounting their assault from the trees in our yard.
Signature: Puzzled.

Swarming Caddisflies

Dear Puzzled,
Your photo documents an amazing population explosion, but we wish you had a nice closeup of a single individual.   We believe these light seeking insects are Caddisflies in the order Trichoptera, and BugGuide indicates:  “Species most diverse in well-aerated streams, but also occur in lakes, ponds, and marshes. Adults rest on nearby vegetion during the day; flight activity begins at dusk. Adults are attracted – sometimes in great numbers – to artificial light.”

Caddisflies Swarming, we believe

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