The term “midge” refers to a diverse collection of small flying insects belonging to the order Diptera (true flies). Found globally, they are common near bodies of water and often appear in large numbers. Midges are frequently mistaken for mosquitoes due to their delicate appearance, but they represent several different insect families. Their behaviors range from being a harmless nuisance to a painful pest. Understanding the distinction between biting and non-biting types is key to identifying and managing their presence.
Defining the Midge Fly
Midges are characterized by their small size, typically measuring between 1 and 5 millimeters in length, with fragile bodies and long, slender legs. Like all true flies (Diptera), they possess a single pair of functional wings. A distinguishing feature, especially in males, is the presence of feathery or “plumose” antennae, giving them a fuzzy-headed appearance. Non-biting midges lack the elongated, piercing mouthparts that mosquitoes use to feed.
Biting Versus Non-Biting Midges
The primary distinction among midges is the presence or absence of a biting mechanism, separating them into two main families.
Non-biting midges belong to the family Chironomidae and are often called “lake flies” or “blind mosquitoes.” Adult Chironomids do not feed on blood because their mouthparts are non-functional. They pose no threat to humans beyond being a nuisance when they aggregate in dense clouds. These midges are often attracted to lights and can accumulate on structures, leading to property staining.
Biting midges belong to the family Ceratopogonidae and are known as “no-see-ums” or “punkies,” reflecting their minute size and painful bite. Females possess specialized mouthparts that allow them to pierce skin and take a blood meal for egg development, similar to a mosquito. The resulting bite is irritating, often causing an itchy, burning welt. Beyond the nuisance and irritation, certain species of biting midges can transmit pathogens that affect livestock, such as Blue Tongue virus, giving them veterinary significance.
Life Cycle and Swarming Behavior
Midges undergo complete metamorphosis, progressing through four distinct stages: egg, larva, pupa, and adult. The female lays a gelatinous mass of eggs on or near an aquatic habitat, such as a pond, lake, or stream. The larval stage is entirely aquatic or semi-aquatic, living in the sediment and feeding on organic matter. Some chironomid larvae are known as “blood worms” due to their reddish color, which comes from hemoglobin allowing them to survive in low-oxygen conditions.
The larval stage can last from a few weeks to several months before the larva transforms into a pupa. The pupa floats to the water’s surface, and the adult emerges to take flight. Swarming behavior occurs shortly after emergence, typically around dawn or dusk, and is primarily a mating ritual. These dense clouds are composed mostly of males, which gather to attract females for mating.
Managing Midge Populations
Controlling midge populations starts by addressing the aquatic environments where they breed. Reducing standing water or organic-rich sediment is an effective preventative measure, as midge larvae feed on the debris that accumulates in these sites. For larger water bodies, introducing natural predators, such as certain species of fish, can manage the larval population biologically.
For personal protection against adult midges, physical barriers and repellents are the most effective strategy. Installing fine-mesh screens on windows and doors prevents the insects from entering structures. Applying insect repellent to exposed skin deters biting midges, and wearing light-colored clothing is helpful since some species are attracted to darker fabrics. Chemical treatments, such as larvicides or adulticides, are sometimes used for large-scale control but often provide only temporary relief.