Crane Flies: Mosquito Hawks Don’t Eat Mosquitoes

Crane flies turn up in clouds twice a year and get mistaken for giant mosquitoes. For the spider and harvestman side of the “daddy long legs” name, our daddy long legs guide untangles all three animals.

Crane fly or mosquito? The quick answer

Compiled by The Pest Control Brief from Orange County Mosquito and Vector Control District, University of Kentucky Entomology, University of Arizona and our mayflies guide (University of Minnesota Extension and UF/IFAS). Mosquito lifespan from our mosquito lifespan guide.

The single most reliable field mark is the one the University of Kentucky’s Critter Files points to: a V-shaped suture across the top of the thorax.

What is a crane fly?

Crane flies are true flies in the order Diptera. Orange County Vector Control counts about 14,000 described species worldwide and more than 1,500 in North America. Most Kentucky species in the common genus Tipula are 3/4 to 1 inch long and grey or brown, according to the University of Kentucky, while Ctenophora species are shiny black, some with red or orange markings that look wasp-like.

Do crane flies bite?

No. Orange County Vector Control puts it plainly: not a single species of crane fly can bite, and they cannot sting. The University of Kentucky adds that adults do not harm humans, animals, plants, food or homes.

Do crane flies eat mosquitoes?

No. Oregon State University Extension notes the nicknames “mosquito hawk” and “skeeter eater” and states that crane flies do not consume mosquitoes. The University of Kentucky gives the one honest footnote: some crane fly larvae living in streams are predatory and may occasionally eat mosquito larvae.

Our iNaturalist analysis shows why the myth sticks. Crane fly sightings peak in May and again in September, while mosquito sightings climb through summer to a peak in September. In early autumn the two fly at the same time, which may be why the big one gets credited with hunting the small one. If you want animals that genuinely eat mosquitoes, our guide to what eats mosquitoes covers the real predators.

What do crane flies eat?

• Adults: very little or nothing. The University of Kentucky says many species do not eat at all and some are believed to take nectar. Oregon State says adult European crane flies do not feed but do drink water. University of Arizona coverage notes they spend much of their time motionless to save energy.
• Larvae in soil: mostly decaying vegetation and associated organic matter. Some soil species eat living plant roots, and the two invasive European species eat grass roots, crowns and blades.

Why are there crane flies everywhere?

Because most of a crane fly’s life is hidden. The University of Arizona estimates that about 95 per cent of a crane fly’s life is spent as a larva, which can last three years or more in some species. Adults then emerge together. The University of Kentucky says adults are especially common around homes in spring and early fall; Oregon State says European crane fly adults live above ground in the first two weeks of September; Cornell gives late July to early September for New York, with a second spring flight of the common crane fly in late April to early May.

Wet weather triggers big years. In Tucson, University of Arizona ecologist Michael Bogan links mass emergences to heavy autumn and winter rain, citing the wet winters of 2010, 2015 and 2017; in dry years the larvae stay dormant in the soil.

Where do crane flies come from?

From the ground beneath you or from nearby water. Females lay eggs in moist or wet soil, often along creeks and sometimes in overwatered lawns, according to Orange County Vector Control. A lawn full of crane flies in September has usually produced them itself.

What attracts crane flies?

Two things: wet soil to lay eggs in, and lights at night. Oregon State says egg-laying adults search for wet soil in early September, and Bogan notes that adults are drawn to porch lights and fly indoors when doors are open. Poorly drained, low-lying turf is where the University of Kentucky says the rare damaging populations build up.

Crane fly lifespan and life cycle

Adults live 1 to 3 days on average (Orange County Vector Control) to two weeks at most (University of Arizona). The egg and larval stages take up nearly all of the year.

Compiled by The Pest Control Brief from Oregon State University Extension EM 9296, Cornell Integrated Pest Management and the Northeastern IPM Center.

The iNaturalist records match this biology closely. Records of the European crane fly are almost entirely from August to October, while the common crane fly shows two peaks, April and September, exactly the two generations Cornell describes.

Are crane flies harmful?

To people, pets and homes, no: Orange County Vector Control lists them as no health threat, and the University of Arizona says they carry no diseases. The University of Kentucky calls most crane flies beneficial decomposers, and they feed birds, bats, spiders and fish.

The exception is the lawn. Oregon State says that of the several crane fly species in the Pacific Northwest, only the marsh or common crane fly and the European crane fly damage turfgrass. Both are invasive, from Europe and northern Africa. The European crane fly was first detected in western North America in 1965, and Cornell entomologists found both species in western New York in 2004, the first report in the eastern United States. Cornell’s 2026 fact sheet now describes both as established across the majority of continental US states.

Which states report the European crane fly?

Adjusted for observer numbers, iNaturalist records put Vermont, Maine, Alaska, Washington and New York on top. Treat this with care: there are only 1,064 US records, Vermont’s lead rests on 140, and sightings follow observers. Published lawn damage is in the Pacific Northwest, with outbreaks in Bend and Spokane according to Oregon State, and in New York and the Northeast.

How big are crane fly larvae, and what does lawn damage look like?

Leatherjackets are grey to brown, legless and worm-like, with tough skin and no obvious head. European crane fly larvae reach 1 to 1.5 inches (25 to 38 mm) by December, according to Oregon State; Orange County Vector Control gives up to 2.4 inches for the giant western crane fly.

Damage signs, from Oregon State, Cornell and the Northeastern IPM Center:

• Thinning turf from February, progressing to bare patches in wet, low-lying areas by April and May.
• Yellow spotting and scalped patches that look like cutworm damage.
• Birds, skunks and raccoons digging for the larvae, which adds to the damage.
• Papery pupal cases sticking out of the turf after adults emerge.
• Large numbers of adults hovering just above the grass in May and September, which native crane flies do not do.

How to get rid of crane flies

Crane flies in the house

No treatment is needed: they do not breed indoors and die within days. Put them out in a cup, keep doors shut at dusk and dim outdoor lights during the September flight.

Crane fly larvae in the lawn: count first

Cut out a 6 by 6 inch square of turf 1 to 2 inches deep, or a 4-inch cup cutter core, pull it apart and count. Multiply a 6 by 6 inch count by 4, or a cup cutter count by 11.5, to get larvae per square foot, and average three or four spots, sampling at the edge of damage rather than in bare patches.

Timing: the part most people get wrong

Compiled by The Pest Control Brief from Oregon State University Extension EM 9296, WSU HortSense, UC IPM Turfgrass Pest Management Guidelines, Cornell IPM and the Northeastern IPM Center.

The difference is regional. In the Pacific Northwest, larvae do most of their feeding through winter, so a spring treatment arrives after the damage. In New York, damage peaks when the larvae are largest in early to mid May, and the common crane fly’s second generation adds an autumn window.

Fix the lawn before reaching for insecticide

1. Dry out the egg-laying window. Oregon State advises cutting back irrigation around Labor Day, when adults seek wet soil; eggs and young larvae die in dry soil, and turf needs less water then.
2. Fix drainage. French drains, drain tile and aeration reduce the saturated soil the larvae need.
3. Remove excess thatch, which UC IPM calls ideal larval habitat.
4. Let the predators work. UC IPM reports natural losses of up to 50 per cent from birds, ground beetles and other causes, and WSU notes starlings and robins often bring numbers below damaging levels by spring.
5. Consider beneficial nematodes. UC IPM says drenches of Steinernema feltiae may give up to a 50 per cent reduction if properly applied.

If a count is still above threshold, insecticide is a lawn job, and Oregon State notes some products need a state applicator’s licence. Follow the label, which is the law, and avoid treating when weeds or flowers in the lawn are in bloom, since many turf insecticides are toxic to bees. A general pest control contract usually does not cover turf, as our lawn pest control guide explains.

Frequently asked questions

Are crane flies good or bad?

Mostly good. The University of Kentucky describes most crane flies as beneficial decomposers whose larvae break down decaying plant material in soil and streams, and both larvae and adults feed birds, bats, spiders and fish. They are only a problem where the invasive European and common crane flies build up in wet, poorly drained lawns, and even there a count of larvae decides whether anything needs doing.

Do crane flies keep mosquitoes away?

No. Adult crane flies are not predators and do not eat mosquitoes, despite the names “mosquito hawk” and “skeeter eater”, according to Oregon State and the University of Kentucky. Most adults barely feed at all. A few stream-dwelling crane fly larvae may occasionally eat mosquito larvae, but having crane flies around the house does nothing to reduce mosquito bites.

What attracts crane flies?

Moist soil and lights. Egg-laying females look for wet ground, including overwatered or poorly drained lawns and creek edges, and adults gather at porch lights and slip indoors through open doors at night. Cutting back irrigation in early September and dimming outdoor lights during the autumn flight are the two changes that make the most difference around a house.

How to get rid of crane flies?

Indoors, simply put them outside; they die within days and do not breed inside. In the lawn, count larvae per square foot first, because extension services advise treatment only above about 25 per square foot in healthy turf. Improve drainage, reduce late-summer watering and remove thatch, and time any insecticide for your region: winter in the Pacific Northwest, autumn or May in New York.

How long do crane flies live?

The adult stage is short: 1 to 3 days on average according to Orange County Vector Control, and two weeks at most according to the University of Arizona. European crane fly larvae spend about 11 months in the soil, and in some species the larval stage lasts three years or more, which is why big flights can appear suddenly after wet years.

Sources

• Oregon State University Extension, EM 9296, Managing Crane Fly in Lawns (Kowalewski, Edmunds, McDonald and Braithwaite), 2020, reviewed 2024.
• Cornell Integrated Pest Management, European Crane Flies (Tipula paludosa and Tipula oleracea) Ornamental IPM Fact Sheet (Worth and Wickings), updated May 2026.
• Peck, D.C., European Crane Fly, NYS Integrated Pest Management Program fact sheet, Cornell University, 2006.
• Cornell Chronicle, Cornell experts find two new species of crane fly have invaded New York, 2005.
• Northeastern IPM Center, School IPM Best Practices: European Crane Fly.
• University of California Statewide IPM Program, Turfgrass Pest Management Guidelines: Crane Flies.
• Washington State University HortSense, Lawn and Turf: European Crane Fly, reviewed 2026.
• University of Kentucky Department of Entomology, Kentucky Critter Files: Crane Flies (Newton), 2005, updated 2008.
• Orange County Mosquito and Vector Control District, Crane Flies fact sheet, 2019.
• University of Arizona News, What’s up with all the crane flies? (interview with Michael Bogan).
• University of Minnesota Extension and UF/IFAS, mayfly sizes, as compiled in our mayflies guide.
• The Pest Control Brief analysis of iNaturalist research-grade records, pulled October 2026.