Midges – Clouds of Them

Q: When I run near the Chattahoochee I often pass through clouds of tiny insects. What are they?

A: They’re probably midges. Ohio State University experts describe these swarms of CHIRONOMID MIDGE FLIES (Family Chironomidae)   “The cloud-like clusters of these small insects can be hauntingly beautiful as thousands of gossamer wings reflect the early morning or evening sunlight.  However, the observer’s perspective on the beauty of the swarms may change a bit once they learn the sordid details of inner workings within the swarms.

“The midge masses are called “mating swarms,” and for many midge species the swarm is composed of a throng of lovesick male midge flies.  Swarms may be massive numbering in the thousands.  Every now and then, an adventurous female midge will try to fly through the aerial mass of zooming, swooping amorous males.  The males fly with their legs outstretched in the hope they will snag the female … to get acquainted.  Love is in the air!

“Midge flies are very small, measuring no more than 3/8” in length.  They resemble mosquitoes with their delicate wings and legs, and they make an audible “buzzing” sound when they fly.  However, midge flies do not bite and male midges flies have large, conspicuous fern-like or “feathery” (= plumose) antennae.  Also, mosquitoes do not typically gather in close-flying swarms … unless it’s a Stephen King movie.

“There are over 760 species of Chironomid midge flies in North America.  Midge fly larvae live in many types of aquatic or semi-aquatic habitats.  These habitats include water in pools, ponds, lakes, slow moving streams, drainage ditches, clogged drainage tiles, containers, clogged rain gutters, and in some cases, wet soil or seepage areas.  Occasionally, over-irrigated turfgrass will provide ideal midge fly larval habitat.  Most species of midge fly larvae feed on living or decaying plant matter and are an important part of aquatic food chains.  Many species can survive in very stagnant or polluted water.  Some of the aquatic forms live in tubes or cases composed of fine particles of the substrate cemented together with salivary secretion.

“Some Chironomid midge fly larvae have hemoglobin in their blood which gives them a blood-red color, and the common name of “bloodworms.”  Note that the common name is spelled as a contraction to differentiate from marine “blood worms” (Glycera dibranchiata) which are “true worms” (Phylum Annelida) and are prized as fish bait.  Such are the challenges with common names!

“Chironomid midge flies are considered “beneficial” owing to their status as “decomposers” in aquatic ecosystems and because they serve as an important food item at the base of aquatic food chains.  While their swarms may re-appear in the same locations for several days, they are usually just a nuisance to joggers and bicyclists passing through.  However, large numbers of mating swarms have been known to present a traffic hazard because of smashed midge bodies on windshields.  Of course, it is assumed some of the midges died with a smile on their midge faces!”