Florida’s coastal marshes and mangrove swamps are home to a vast army of biting midges—microscopic flies that leave a big impression. Often called “no-see-ums,” these insects thrive in the Sunshine State’s heat and humidity, making outdoor living a constant battle.
What Are Biting Midges?
Biting midges belong to the family Ceratopogonidae, and the most familiar genus is Culicoides. Measuring less than 1/8″ long, these flies use tiny cutting teeth on elongated mandibles to feed on blood. Only the females bite; males feed on nectar and other sugar sources. Their bites are notorious for causing intense itching and raised pustules that can linger for days.
Distribution in Florida
Culicoides species occur worldwide; 47 species are known in Florida.
In southeast Florida’s coastal counties, Leptoconops species also appear, especially in salt-marsh and mangrove habitats.
Some Culicoides favor highly organic, wet soils near livestock operations, such as cattle-farm runoff ponds.
These insects do not establish indoors; they breed and develop entirely outdoors in moist substrates.
Immature Stages: Eggs, Larvae, and Pupae
Eggs
– Cigar-, banana-, or sausage-shaped, about 0.25 mm long.
– White when laid, turning brown or black.
– Laid only on moist soil; cannot withstand drying.
– Hatch in 2–10 days, depending on species and temperature.
Larvae
– Creamy white, 2–5 mm long, worm-like in appearance.
– Four instars; first instar has a spine-bearing proleg.
– Live in salt marshes, mangrove swamps, pond edges, tree holes, and other moist substrates.
– Feed on small organisms; require moisture but can develop just below the air–water interface.
Pupae
– Pale yellow to dark brown, 2–5 mm long.
– Possess tubular respiratory horns on the unsegmented cephalothorax.
– Spiny integument used for species identification.
– Pupal stage lasts 2–3 days before adult emergence.
Adult Midge Morphology
Less than 3 mm long, gray in color.
Wings bear dense hairs and species-specific pigment patterns.
Compound eyes nearly meet above the antennal bases.
Antennae are 15-segmented; male pedicel houses Johnston’s organ.
Females have a proboscis with cutting teeth for blood-sucking; males lack these teeth.
Abdomen is nine-segmented and tapers to a point. The thorax slightly overhangs the head, giving a hunched appearance.
The Complete Life Cycle
Biting midges undergo complete metamorphosis (holometabolous development) in 2–6 weeks under optimal conditions:
- Egg Stage
– Females deposit 25–110 eggs per blood meal directly on moist soil.
– Some species produce up to seven egg batches in their lifetime.
– First batch may be laid without a blood meal in autogenous species. - Larval Stage
– Four instars feed on organic matter and microorganisms.
– Development spans 2 weeks to over a year, based on species and environment. - Pupal Stage
– Nonfeeding; respiratory horns reach the water surface if submerged.
– Lasts 2–3 days before adult emergence. - Adult Stage
– Males often emerge days before females and form mating swarms.
– Females take blood meals at dawn or dusk to mature eggs.
– Adults disperse up to 2 km (females) in search of hosts and breeding sites.
– Lifespan ranges from a few weeks in nature to 2–7 weeks in laboratory settings.
Medical
Allergic Reactions: Bites can cause painful welts, intense itching, and pustules that last up to 10 days.
Vector Roles:
• Mansonella filarial worms in the Caribbean and South America.
• Bluetongue virus transmission to sheep and cattle, primarily by Culicoides sonorensis.
• African Horse Sickness virus in equines (sub-Saharan Africa).
• Epizootic Hemorrhagic Disease virus in deer and other ruminants.
Economic and trade impacts arise when livestock movements are restricted from bluetongue-endemic areas.
How to Manage and Prevent
Targeting biting midges requires focus on immature habitats; adult treatments are inefficient:
Larval Habitat Control
• Historically, marsh impoundment, diking, and drainage reduced breeding sites.
• Larval habitats cover vast areas; environmental impacts make large-scale habitat alteration impractical.
Adult Insecticide Applications
• ULV sprays or fogs may kill local adults but midges continually immigrate from untreated habitats.
• Daily applications would be required—unsustainable and environmentally unsound.
Personal and Structural Barriers
• Install fine-mesh screening (<16 mesh) on windows, doors, and patios to block midges.
• Use high-speed ceiling or window fans to create airflow that midges cannot overcome.
• Apply DEET-based repellents on exposed skin.
• Use barrier sprays and portable foggers labeled for no-see-ums around seating areas.
Because adult control alone cannot suppress these flies long-term, integrated approaches focusing on habitat modification, exclusion, and personal protection are essential for reducing biting midge impacts in Florida.
Pestherapy Inc. can help manage no-see-ums and small flies.
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Our trained technicians inspect for conducive conditions on each visit, apply targeted products and
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