Midges are a general term for many small, gnat-like flying insects from various families within the suborder Nematocera. These tiny flies are globally distributed, found in most land areas except deserts and frigid zones. While some midge species are harmless decomposers or food sources, others are known for nuisance swarming or painful bites.
Identifying a Midge
Midges are generally small, delicate insects, typically measuring between 1 to 5 millimeters in length, though some can be even smaller. Their bodies are slender, often gray, brown, or black, and they possess two delicate wings, which lack the scales found on mosquito wings. Unlike mosquitoes, which have elongated piercing mouthparts, most midges have shorter mouthparts and are not equipped for blood-feeding.
A distinguishing characteristic for many midge species is how they position their legs when at rest; they often hold their first pair of legs forward and upward, which can sometimes be mistaken for antennae. Male midges frequently exhibit feathery or plumose antennae, used to detect the high-pitched sounds of female wings. Midges commonly engage in swarming behavior, particularly at dawn and dusk, where males gather in aerial groups, sometimes appearing as dancing clouds over water or lawns.
Common Midge Types
Non-biting midges, primarily Chironomidae (lake flies or phantom midges), do not possess piercing mouthparts and are harmless to humans, though their large swarms can be a nuisance near water bodies. Chironomid larvae, sometimes called “bloodworms” due to their red color, are important indicators of water quality and a food source for aquatic animals.
Biting midges, from the family Ceratopogonidae, are known as “no-see-ums” or “punkies” in North America, and “sandflies” in Australia. These insects are typically less than 3 millimeters long; females feed on blood for egg development, delivering painful bites. Black flies (Simuliidae) are another biting group, characterized by their small, hump-backed appearance and daytime biting habits. They lay eggs in fast-flowing water, and females require blood meals for reproduction, sometimes transmitting diseases to livestock or humans.
Midge Life Cycle and Environment
Midges undergo complete metamorphosis, progressing through four distinct life stages: egg, larva, pupa, and adult. Females typically lay their eggs in aquatic or semi-aquatic environments, either directly on the water surface, on submerged vegetation, or in damp soil. Depending on the species and environmental conditions, these eggs hatch into larvae within a few days to a month.
The larval stage is predominantly aquatic, with larvae residing in mud, sediment, or moist soil at the bottom of water bodies, where they feed on organic detritus, algae, and microorganisms. Larvae can remain in this stage for several weeks to many months, even overwintering in colder climates. After developing through several instars, larvae transform into pupae, which are also aquatic and typically rise to the water surface before adult emergence. The adult midge then emerges, and its lifespan is relatively short, often lasting only a few days to a couple of weeks, primarily focused on mating and egg-laying.
Dealing with Midges
Preventing midge infestations begins with managing their breeding grounds. Eliminating sources of standing water around homes and properties, such as in bird baths, clogged gutters, or poorly drained areas, can significantly reduce midge populations. Improving drainage and ensuring proper landscaping to direct water away from structures also helps to deter midges.
For personal protection, using insect repellents containing active ingredients like DEET or picaridin on exposed skin can help prevent bites from species that feed on blood. Wearing protective clothing, especially during peak midge activity times like dawn and dusk, can also minimize exposure. Indoors, installing fine-mesh screens on windows and doors can prevent midges from entering, as they can often pass through standard screens due to their small size. Using fans can disrupt midge flight due to their weak flying ability, and switching to yellow or amber outdoor lights can make areas less attractive to them. In cases of severe infestations, particularly with biting species, professional pest control services might be necessary to employ targeted treatments like EPA-registered insecticides or larvicides.