2012-05-19 / Columnists

Nature Notes

Midges Are Harmless, Annoying - And Plentiful This Season
By Patricia Martin

If you’ve been around the Island or by the docks in St. Ignace or Mackinaw City in the last few weeks, you’ve probably been inundated with swarms of small black flies, which seem to cover almost every surface, and appear in great clouds of black. Every morning for the last two weeks, I’ve had to sweep what seems like millions of the little creatures off the porch, not to mention the ones I’ve inhaled while biking. A little extra protein, I guess.

These bugs are in the order Dipterid, suborder Nematocera. This suborder includes mosquitoes, crane flies, gnats, black flies, and the creatures we’ve been having problems with, the midges. All of the above mentioned creatures are elongated flies with segmented antennae. Most of them have aquatic larvae in their life cycles.

The non-biting midges are what we’ve been dealing with recently. Initially, many folks who see them think that these are swarms of gnats or mosquitoes, but the non-biting midges don’t go for blood. These non-biting midges are found near lakes, ponds, or streams, and may dance in swarms over the water, sometimes inciting fish to jump. Most occur in huge swarms or small compact mating swarms. Often, after sunset, adults become active and fly into nightlights, getting into the smallest openings in structures. These creatures pose no threat to pets or people, and are an important part of the food chain for local and migratory waterfowl, not to mention other insectivores, like frogs. They can be a nuisance when they land in wet paint, or get inhaled.

Male midges form large swarms when the temperature, humidity, and light conditions are right for their species. Different species swarm under different environmental conditions, and usually at different times of the day. When more than one type of midge is present in an area, it may seem that they’re constantly swarming. Adult midges have a short life span, their function being merely to swarm, mate, and lay their eggs.

Adult Male Midge Adult Male Midge Non-biting midges are small (one-eighth to one-half inch long), delicate, mosquito-like, but lack scales on their wings. Adults are humpbacked and are brown, black, orange, or gray. They lack the long beak (proboscis) of the mosquito, and males have very feathery antennae. The adult midges can be easily identified by the flattened, almost smashed, appearance they have when resting on any surface. Other midge-like insects and mosquitoes appear to be standing on the ends of their legs, with their bodies clearly not touching the substrate. Larvae are often whitish cylindrical, elongate or wormlike, about one-half inch long, often with a dark head. Some are known as bloodworms, or red worms, owing to the presence of hemoglobin in the blood. Most live in fresh water, while some are found in wet soil, moss, and under damp bark. Most larvae feed on algae or small aquatic plants.

Biting midges, punkies, or nosee ums are very tiny (less than one-quarter inch), slender-bodied, gnat-like flies. Some have narrow spotted or clear wings. The larvae are tiny, whitish, elongate, or wormlike, and are found in sand, mud, decaying vegetation, and water in tree holes.

Crane flies are small to large (three-sixteenth to one inch), long-legged, and slender-bodied with a V-shaped structure across the thorax. Legs of all species break off easily. Many have patterned wings, and resemble mosquitoes.

Non-biting midge females lay eggs in masses over open water or attached to vegetation. These eggs hatch in about 72 hours, and the young larvae drop to the bottom of the lake, stream, etc. feeding on organic debris. The larval stage takes about four weeks, followed by pupation lasting about 48 hours. The pupae emerge and rise to the surface of the water. The adults don’t eat during the five to 10 days of their lives. The males swarm at dusk, with mating occurring after the females enter the swarm. Midges winter over in their larval stage, where they are beneficial as important food items for fish and aquatic animals.

As far as controlling the midge population, there is really no good way when you’re near large bodies of water. To prevent them near your house, change your outside light to a sodium vapor or halogen light with a pink, yellow, or orange bulb (the yellow “bug lights” as we used to call them). They’re not as attractive to the midges as 100-watt mercury vapor light.

The great swarms of the midges should soon decrease as conditions change, so perhaps we won’t have too many more days of their presence.

P.S. The first lilac burst into flower Monday, May 14, in my backyard. This is three days earlier than the previous record on that particular shrub.

Trish Martin is a year-around resident of Mackinac Island, has earned a master’s degree in botany from Central Michigan University, and owns Bogan Lane Inn.

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