Midge Fly

Marquette, Michigan

June 1, 2022

I first encountered these suckers on the shores of Lake Huron -- they swarmed all over me. Between these and the mosquitoes, I have seen enough insects for a while. And like this article says, they make a mess of your car!

A group of insects found in the Great Lakes region known as chironomids or midge flies play an important ecological role in and around the Great Lakes. The larval state of the midge fly, often referred to as a bloodworm, lives on the bottom of a lake or stream. The larval state of this insect is called a bloodworm because of the hemoglobin that they contain giving them the blood red appearance. Just like our hemoglobin that is used to bind oxygen in our blood stream the larval midge fly also uses hemoglobin to extract oxygen from the water.

On the bottom of a lake or stream the larval midge fly feeds on algae and detritus where they live in tubular holes in the sediment. They construct small tubes made up of dead leaves or particles of sand or clay fastened together with viscous threads. These tubes at times can be seen on submerged stones or aquatic vegetation. Since the larval midge fly contains hemoglobin they can live in oxygen depleted mud. They can also live freely amongst the bottom debris or aquatic plants and at times venture into the water column where they are vulnerable to predators such as fish.

Adult midge flies are short lived after emergence from the water and survive for only several days for reproduction. They form massive clouds in the air where the females and males mate. It is at this time that they provide valuable food for birds and bats. The massive swarming behavior of the midge fly can create a nuisance for humans especially if they are encountered along the highway where they can quickly grease up windshields and headlights.