A Midge or Mosquito?
Midges, aka "gnats" or "rice flies", are common names that generally define any number of small, non-biting flies with two wings. Chironomid midges (non-biting flies in the family Chironomidae) are the most common midges encountered in Lake County. These pestiferous, but harmless insects are often confused with mosquitoes. This is because midges look similar to mosquitoes and their immature stages share many of the same water sources. Like mosquitoes, midges can survive in polluted, stagnant water. Here in Lake County our primary source for midges is Clear Lake. In fact, the Clear Lake Gnat (Chaoborus astictopus) or Phantom Midge, is native to Clear Lake and was a major pest concern due to its sheer abundance in the 1940s-1970s.
Commonly Encountered Midges
- Clear Lake Gnats (Chaoborus astictopus): Clear Lake gnat adults have reduced mouthparts and are not known to bite. They are much smaller than mosquitoes and other midges of Clear Lake and can pass through large window screens. These gnats are also called "Phantom Midges", because the larvae are transparent making them very difficult to see. There are 4 larval stages (instars) and 4th instar larvae migrate up and down in the water column. During the day they stay in the sediment and at night they move to the surface. Historically, they emerged in large numbers off of Clear Lake, creating a nuisance for local residents.
- Chironomids (various species, most common is Chironomus plumosus): This is the largest midge in North America and is common around Clear Lake in the spring and summer. Larvae, commonly called "Bloodworms", are usually reddish in color as a result of hemoglobin in the lymph system. Larvae live in the mud, so they filter feed on organic debris on the lake bottom. They also build "horseshoe" shaped tubes around their bodies and circulate water through these tubes. Adults emerge in large plumes and can form mating swarms in the evening that can be readily seen by residents living near the lake.
Another mosquito look-alike
Crane Flies (aka "mosquito hawks" or "mosquito eaters"): These delicate flies with stilt-like legs are commonly seen in and around homes. They vary in size, but can be as large as 1.5 inches in length. They are often confused with mosquitoes or as "mosquito eaters", however they do not bite people and do not eat mosquitoes. In fact, many adults have short life spans and do not eat at all. Crane fly larvae are commonly found in loose soil or organic matter, although some species can emerge from aquatic sources.
Is it a midge or a mosquito?
Midges, like the one pictured, raise their forelegs at rest, while mosquito adults do not.
The wings of midges are shorter than their body, while mosquito wings are slightly longer than their body.
Midges have nonfunctional (reduced) mouth parts, while mosquitoes have a long proboscis (needle like projection).
Midges form large mating swarms in the evening, which may occur over serveral days. While male mosquitoes may swarm when mating, they are typcially in a defined location and difficult to see.
Midges only live long enough to mate and lay their eggs, while certain species of mosquitoes can live for months at a time.
Midges are highly attracted to light, so minimizing the use of outside lights will help to reduce their presence near your home. Should you choose to use a "Bug Zapper", keep it as far away from your residence as possible to maximize its effectiveness. Keep doors and windows closed or tightly screened to prevent midges from entering your home. Using insecticides to control midges is NOT recommended, as more gnats will quickly re-enter the area that was treated. Remember, these midges are harmless and have very short life spans so any nuisance they pose will be temporary and intermittent. Midges are important to the food chain as they provide food for fish and other aquatic animals.