Dozens of animals eat flies and mosquitoes, from bats and birds to dragonflies, spiders, fish, and frogs. These insects are small, abundant, and packed with protein, making them a food source for predators across nearly every ecosystem. Some of these predators are impressively efficient: a single dragonfly can eat over 100 mosquitoes in a day, and a little brown bat can catch 1,000 mosquito-sized insects in a single hour.
Dragonflies and Damselflies
Dragonflies are among the most effective mosquito and fly predators on the planet. They’ve been hunting these insects for over 100 million years, and they target both the larval and adult stages. Adult dragonflies can eat more than 100 mosquitoes per day, snatching them mid-flight with speed and precision that few other insects can match.
The immature forms of dragonflies and damselflies, called naiads, live underwater and feed heavily on mosquito larvae before they ever become flying adults. A 2023 meta-analysis found that a single naiad eats an average of 40 mosquito larvae per day, reducing the local larval population by roughly 45% per day in experimental settings. This makes them one of the few predators that attack mosquitoes at the life stage where control is most effective.
Bats
Bats are the primary predators of night-flying insects, and mosquitoes and small flies are part of that diet. The little brown bat is often cited as a mosquito-eating powerhouse. According to the U.S. Forest Service, a single little brown bat can catch 1,000 mosquito-sized insects in an hour. A nursing mother eats approximately 4,500 insects every night.
That said, the actual impact bats have on mosquito populations is less clear than the raw numbers suggest. A study from the University of Wisconsin-Madison found that while bats do eat mosquitoes, there’s little evidence yet that they suppress mosquito populations in a meaningful way at a landscape level. Bats eat whatever small flying insects are most available, so mosquitoes may make up a relatively small portion of their total diet on any given night. They’re still valuable pest controllers, particularly for agricultural insects, but installing a bat house won’t necessarily solve a mosquito problem in your yard.
Birds
Several bird species feed on flies and mosquitoes, though the degree varies more than many people assume. Barn swallows are among the most effective, sweeping through clouds of insects in open fields and near water. They’re one of the most widespread swallow species in the world and eat large quantities of small flying insects throughout the breeding season. Downy woodpeckers, the smallest woodpecker in North America, also include mosquitoes as a significant part of their summer diet.
Purple martins, on the other hand, have a reputation for mosquito control that doesn’t hold up. A seven-year study at the Purple Martin Conservation Association headquarters in Pennsylvania found not a single mosquito in the birds’ diet. Older studies from the 1960s and 1970s reached similar conclusions. Purple martins feed during the day and at higher altitudes than mosquitoes typically fly, so the two rarely cross paths. If you’re putting up a purple martin house specifically for mosquito control, it probably won’t help much.
Spiders
Spiders are generalist insect predators, and flies and mosquitoes frequently end up in their webs. Globally, spiders consume an estimated 800 tons of insects per year, with mosquitoes and flies making up a portion of that total. Web-building spiders near porch lights or water sources are especially likely to catch mosquitoes and house flies drawn to those areas. Jumping spiders and other active hunters also pick off small flies they encounter on walls and vegetation.
Fish
Mosquitofish (Gambusia affinis) are the most well-known aquatic predator of mosquito larvae. A single adult mosquitofish can eat up to 100 mosquito larvae per day, and they’ve been deliberately introduced into ponds, ditches, and water features around the world for exactly this purpose. Many local mosquito abatement districts will even provide them for free.
Other freshwater fish also eat mosquito larvae, including guppies, goldfish, koi, and various minnow species. Any small fish in standing water will reduce the number of mosquito larvae that survive to adulthood. If you have a backyard pond or rain barrel, stocking it with mosquitofish or similar species is one of the more practical ways to cut down on mosquitoes at the source.
Frogs and Toads
Frogs eat adult mosquitoes and flies as part of a broader insect diet, and some species also target larvae. Green tree frogs have been observed actively feeding on mosquito larvae in laboratory settings, and tadpoles of certain toad species prey on early-stage mosquito larvae in shared water habitats. Adult frogs and toads will snap up house flies, gnats, and mosquitoes along with whatever other small insects come within range. They’re opportunistic rather than specialized, so their impact on fly and mosquito numbers depends heavily on how many frogs are in the area and what else is available to eat.
Crane Flies Are Not Mosquito Eaters
One common misconception worth clearing up: crane flies, those large, gangly insects often called “mosquito eaters” or “mosquito hawks,” do not eat mosquitoes. They don’t eat flies either. Many adult crane flies don’t have functional mouthparts at all. They don’t bite or sting humans, and their resemblance to giant mosquitoes is purely coincidental. If you’ve been leaving crane flies alone in your house hoping they’ll take care of the mosquitoes, they won’t.
What This Means for Pest Control
If you’re searching for what eats flies and mosquitoes because you want fewer of them around your home, the most effective natural predators work at the larval stage, not the adult stage. Mosquitofish in standing water and dragonfly-friendly habitats (ponds with emergent vegetation and no fish that eat dragonfly naiads) can meaningfully reduce mosquito numbers before they take flight. Encouraging barn swallows by providing nesting structures near open areas can help with flying insects in general.
For adult mosquitoes and flies, no single predator will eliminate the problem. Bats, birds, spiders, and dragonflies all contribute, but they eat whatever insects are most abundant and accessible, not just the ones bothering you. The most reliable approach combines predator-friendly landscaping with source reduction: eliminating standing water where mosquitoes breed and keeping trash sealed to reduce fly populations.