You're swatting away another mosquito on a summer evening, and the question pops into your head: isn't there something out there that eats these things? You might think of bats or birds first. But the real MVPs, the precision hunters of the mosquito world, are often other flies. Yes, flies. It's a case of the enemy of my enemy being my friend. The answer to "what fly eats mosquitoes?" opens a door to a fascinating world of aerial predators that provide free, effective pest control.
I've spent years observing insects in my backyard and nearby wetlands. The most dramatic mosquito takedowns I've witnessed weren't from swooping birds, but from other insects—specifically, a group of flies that have evolved into absolute masters of hunting on the wing. Let's cut past the generic lists and look at who these predators really are, how they work, and what you can realistically do to get them on your side.
Your Quick Guide to Mosquito-Eating Flies
- The Top Mosquito Predator Flies
- How These Flies Actually Hunt Mosquitoes
- How to Attract Them to Your Garden (The Right Way)
- The Limitations & Real-World Realities
- Your Mosquito Predator Questions Answered
The Top Mosquito Predator Flies
When we talk about flies that eat mosquitoes, we're not talking about your common housefly. We're talking about specialized hunters. The term "fly" here is scientific (order Diptera), covering a huge range of insects. The champions fall into a few key families.
The Robber Fly (Family Asilidae): The Aerial Wolf
If mosquitoes have a nightmare, it's shaped like a robber fly. These are the undisputed top predators. They look like they're built for violence—hairy, with a pronounced "beard" (mystax) to protect their face from struggling prey, and enormous eyes for tracking movement. Their most terrifying feature is a short, stout proboscis designed to stab prey, inject neurotoxic saliva to liquefy its insides, and then suck it dry.
I remember one hot afternoon watching a large robber fly (looked like a Promachus species) perched on a fence post. A mosquito flew by, and it was over in a blink. The robber fly launched, intercepted it mid-air with an audible click, and returned to its perch to consume it. Total efficiency. They don't just eat mosquitoes; they eat any insect they can catch, including other flies, bees, and butterflies. They're apex insect predators.
Their lifecycle adds another layer of control. Robber fly larvae live in soil, decaying wood, or leaf litter, where they are ferocious predators of other soil-dwelling insect larvae, including potentially beetle grubs and other pests.
The Crane Fly (Family Tipulidae): The Misunderstood Giant
Here's the biggest misconception. The gangly, mosquito-looking crane fly (often called a "mosquito hawk") is harmless as an adult. Most adult crane flies don't eat at all—they live just long enough to mate and lay eggs. The real mosquito-eating action happens in the aquatic or moist-soil environments where their larvae develop.
Crane fly larvae, often called "leatherjackets," are voracious. While many species eat decaying plant matter, a significant number are predatory. These predatory larvae will happily consume mosquito larvae (wrigglers) sharing their same watery habitat—pond edges, water-filled tree holes, saturated soil. They're like the underwater infantry working before the mosquitoes ever take flight.
The Dance Fly & Long-legged Fly (Families Empididae & Dolichopodidae): The Small-Scale Specialists
These are the less flashy but incredibly important predators. Dance flies are often seen in swarms (their "dances") near water. They're small, but many species are carnivorous as adults, snatching tiny insects like mosquitoes and midges from the air.
Long-legged flies are metallic green or blue jewels you see on leaves in sunny spots. They're active daytime hunters, using their excellent vision to stalk and pounce on small, soft-bodied insects. A mosquito landing on a leaf near one is a goner. Their larvae are also predatory in soil or under bark.
| Predator Fly | Life Stage That Eats Mosquitoes | Hunting Style | Key Habitat for Support |
|---|---|---|---|
| Robber Fly | Adult (Larvae eat soil pests) | Aerial ambush & pursuit | Sunny perches, bare soil/sand patches for larvae |
| Crane Fly | Larva (Adults are harmless) | Aquatic predation on wrigglers | Moist soil, pond/stream edges, natural debris |
| Dance Fly | Adult | Aerial capture in swarms | Near freshwater streams, rivers, ponds |
| Long-legged Fly | Adult & Larva | Visual stalk-and-pounce | Sunny foliage, leaf litter, moist soil |
How These Flies Actually Hunt Mosquitoes
It's not random. These predators have evolved specific tactics.
Robber flies are perch-and-wait hunters. They choose a sunny spot with a good view—a twig, a rock, a fence post. Their compound eyes lock onto movement. When a mosquito (or any insect) flies into their zone, they calculate an interception course, take off, and often catch the prey in mid-air with their bristly legs. The stab-and-inject happens instantly. It's brutal and effective.
Dance and long-legged flies are more active searchers. They flit around vegetation, visually inspecting surfaces. Their hunting is closer-range. They rely on stealth and a quick lunge.
The underwater battle waged by crane fly larvae is a slow-motion grapple in the muck. They detect the wriggling of mosquito larvae and use their strong mouthparts to seize them.
How to Attract Them to Your Garden (The Right Way)
You can't buy a bag of robber flies and release them. It doesn't work like that. You attract them by building a supportive ecosystem. This is where most "beneficial insect" advice gets too vague. Here's the actionable plan.
- Stop the broad-spectrum insecticides. This is non-negotiable. Spraying for "bugs" kills every insect—predators first, because they are more active and exposed. You're nuking your own defense force.
- Provide hunting perches and larval habitat. Robber flies need sunny perches. Leave some tall grasses, sturdy flower stems (like sunflowers or Joe-Pye weed), or even install simple insect hotels with open tubes. More importantly, leave some areas of bare, loose soil or a sandy patch undisturbed. That's where their larvae live.
- Create a water feature, but manage it wisely. A small, wildlife pond or even a large birdbath with aquatic plants provides habitat for crane fly larvae and other mosquito predators like dragonfly nymphs. The key is to keep the water moving with a small solar pump or fountain. This deters female mosquitoes from laying eggs there in the first place, while the predators can still thrive.
- Plant diversity, not just pretty flowers. A variety of native plants supports a complex food web. Long-legged flies love hunting on broad-leaved plants in the sun. Dense foliage provides shelter. Let some leaf litter accumulate in garden corners—it's prime real estate for predatory larvae.
The goal is to make your yard a place where these predators can complete their entire life cycle: mate, lay eggs, and have their larvae develop safely. That creates a self-sustaining population.
The Limitations & Real-World Realities
Let's be brutally honest. These flies are not a silver bullet.
If you live next to a massive, untreated swamp, the mosquitoes breeding there will overwhelm any local predatory fly population you foster. The predators work best in a balanced, residential ecosystem where mosquito breeding sources (like your clogged gutters, forgotten buckets, or poorly drained ditches) are also minimized.
Their impact is also seasonal and weather-dependent. A cold, wet spring can delay the emergence of adult robber flies, just when mosquitoes are getting started. Predation is one tool in the box. The most effective mosquito control is integrated: eliminate standing water on your property, use bacterial larvicides (like Bti dunks) in water you can't drain, encourage predators, and use personal protection like repellents when needed.
Your Mosquito Predator Questions Answered
Can I buy flies to control mosquitoes in my yard?
It's not practical or common to purchase adult predatory flies like robber flies or dance flies for release. They are wide-ranging hunters and unlikely to stay in a confined area. The most effective and sustainable approach is habitat management. Focus on creating a welcoming environment for their larval stages by maintaining a small, clean water feature for damselfly nymphs and preserving areas of loose soil or sand for robber fly larvae. This encourages them to establish naturally and provides long-term, self-sustaining control.
Do mosquito-eating flies bite or sting humans?
The primary mosquito predators among flies pose virtually no threat to humans. Robber flies have a fearsome beak for injecting prey, but they lack any interest in human blood—their mouthparts are designed for piercing insect exoskeletons, not skin. Crane flies are physically incapable of biting; adults don't even have functional mouthparts in most species. The only flies that bite humans are those like female mosquitoes, horse flies, and stable flies, which are not the predators we're discussing. You can observe these beneficial hunters without worry.
How effective are flies compared to birds or bats for mosquito control?
Flies are often far more specialized and effective mosquito predators than the popular choices of birds and bats. While a bat may eat thousands of insects per night, mosquitoes often make up a very small percentage of their diet. Research from the American Mosquito Control Association suggests bats are generalists. In contrast, a single predatory fly like a robber fly targets flying insects almost exclusively, with mosquitoes being a preferred snack. Their life cycle also provides double-duty control: the aquatic nymphs of damselflies consume mosquito larvae, while the adults hunt the adults. This makes them a more targeted, life-stage-specific solution than generalist vertebrate predators.
What's the biggest mistake people make when trying to attract beneficial insects?
The most common and damaging mistake is using broad-spectrum chemical insecticides. These products are non-discriminatory; they will kill the predatory robber fly larvae in the soil and the dragonfly nymphs in your pond just as dead as the pest mosquitoes. You wipe out your natural defense army. If you must intervene, use targeted methods like bacterial larvicides (Bti) in standing water, which specifically affect mosquito and black fly larvae without harming other aquatic life. Prioritize creating habitat over applying any chemical.
So, what fly eats mosquitoes? A whole crew of them—from the bulldog-like robber fly to the unassuming long-legged fly. They won't solve a severe infestation alone, but by understanding and supporting them, you're recruiting a powerful, natural ally in keeping your outdoor spaces more enjoyable. It's about working with the ecosystem, not against it. Start by putting away the bug spray and leaving a little patch of your garden just a bit wilder. You might be surprised at who moves in to help.