Midge is the common name for a group of flies called Chironomids. These flies start off as ‘blood-worms’. They are commonly bright red and somewhat iridescent, with a segmented body, legs and a noticeable head. They hatch from eggs a few days after they are laid, at first living in the water, then, as they grow and develop, sinking to the bottom to live in the low-oxygen environment of the mud. They are red because they have a pigment similar to haemoglobin (as in red-blood cells in people) that allows them to be efficient in their oxygen use.
Like all flies, they enter into a pupal stage, and then develop into the winged adults that we call midges. Midges only fly for a short time, only to mate and lay eggs in the water again. In the blood-worm stage they consume detritus and organic matter in sediments, and they are a food source for fish and invertebrates. In the midge stage they actually export nutrients and carbon from the lake (as they fly away and die in other places), and provide food for birds, invertebrates and frogs. They do not sting. They are attracted to lights at night, which is only one of the ways they can be a nuisance. When they appear in large numbers they can make life difficult outside.
Why do we have so many midges?
Midge infestations are an indication that there are a lot of nutrients in the lake, a lot of detritus build up, and that there are not many things to eat them. Nutrient control and restoration of a diverse lake ecosystem are really the only ways to control them.