You may have heard the claim before: one dragonfly can eat 100 mosquitoes a day. Sometimes the number is even higher. It sounds believable. Anyone who has watched a dragonfly patrol a backyard knows how fast and relentless these aerial hunters can be.
But do dragonflies really eat 100 mosquitoes a day, or is that one of those nature facts that became more impressive every time it was repeated online? There is real science behind the reputation. The surprising part is that some of the strongest evidence comes from dragonflies before they ever grow wings.
Where Did the 100-Mosquito Claim Come From?
The number isn’t completely made up. The University of California Agriculture and Natural Resources says a dragonfly can consume anywhere from about 30 to hundreds of mosquitoes per day. Museums Victoria senior entomologist Ken Walker has also described dragonflies as eating about 100 mosquitoes per day. So there are credible entomology sources behind versions of the claim.
The problem is treating 100 as a fixed daily quota. Dragonflies are generalist predators. Mosquitoes are on the menu, but so are midges, flies and other small flying insects. What a dragonfly eats depends on species, habitat, prey availability, weather and time of day. There isn’t good evidence that an average wild adult dragonfly routinely eats exactly 100 mosquitoes every day.
Adult Dragonflies Do Hunt Mosquitoes
Adult dragonflies are extraordinarily capable aerial predators. NC State Extension notes that they catch day-flying insects in flight and that mosquitoes are part of the diet of both adult dragonflies and their aquatic young. Their huge eyes, speed and maneuverability make them remarkably effective hunters.
But there’s an important reality check. A 2015 study published in the Journal of the American Mosquito Control Association examined 41 adult dragonflies and damselflies for evidence of mosquito consumption. Mosquito remains were detected in only four specimens, leading the researchers to question whether mosquitoes are an essential part of the adult diet. That’s a good reminder that being capable of eating lots of mosquitoes doesn’t mean mosquitoes dominate every dragonfly’s menu.
Dragonfly Nymphs May Be the Bigger Mosquito Killers
Here’s where the story gets more interesting. Dragonflies spend much of their lives underwater as nymphs, and those nymphs are predators too. Instead of chasing adult mosquitoes through the air, they can prey directly on mosquito larvae sharing the same aquatic habitat.
A major 2023 meta-analysis published in the Journal of Animal Ecology combined 485 effect sizes from 31 studies involving dragonflies and damselflies. In experimental containers, a single nymph ate an average of about 40 mosquito larvae per day, with a 95% confidence interval of 20 to 60. Mosquito larval populations were reduced by an average of 45% per day under those experimental conditions.
Can Dragonflies Eat More Than 100 Mosquitoes?
They can, at least under certain experimental conditions. A 1980 study indexed by PubMed tested dragonfly nymphs against Aedes aegypti. Medium-sized nymphs consumed an average of 133 mosquito larvae in 24 hours, plus or minus 21. Another study recorded 66 mosquito larvae consumed by a single dragonfly nymph in 24 hours.
Those numbers shouldn’t be turned into a universal rule either. Laboratory containers concentrate predator and prey in ways that don’t necessarily reproduce a backyard pond or wetland. Species, mosquito density, water volume and alternative prey all matter. The newer meta-analysis is especially useful because it looks across many experiments rather than relying on one spectacular number.
Can More Dragonflies Actually Reduce Mosquitoes?
There is evidence they can help. A field experiment found that colonization by dragonfly nymphs produced a clear reduction in mosquito populations in experimental water-filled containers. Research in Southern California has also documented dragonfly nymphs playing an important role in consuming mosquito larvae in natural pools.
But dragonflies aren’t a replacement for mosquito control. UF/IFAS Extension specifically warns against relying solely on natural predators for protection from mosquito-borne disease. Removing standing water, managing breeding sites and using appropriate mosquito-control measures still matter. For more practical prevention steps, see PestMarket’s Mosquito Control Guide.
The PestMarket Verdict
So, do dragonflies eat 100 mosquitoes a day? It’s possible, but 100 shouldn’t be treated as a universal daily average. Adult dragonflies unquestionably eat mosquitoes, and credible entomology sources say individual dragonflies can consume dozens to hundreds under the right circumstances. But wild adults eat many kinds of insects, and research doesn’t establish 100 mosquitoes as the normal daily diet of every dragonfly.
The strongest evidence may actually belong to their underwater young. Dragonfly and damselfly nymphs can consume substantial numbers of mosquito larvae, with a large meta-analysis finding an average around 40 per day in experimental containers and individual studies reporting much higher numbers. The viral claim is oversimplified, but the larger idea is true: dragonflies really are mosquito predators, both above and below the water.
Evidence Grade: STRONG EVIDENCE, WITH AN IMPORTANT CATCH