Do Dragonflies Eat Mosquitoes?

Dragonflies have been eating mosquitoes for at least 100 million years. It was that long ago when scientists believe the first species of mosquitoes evolved and began swarming the planet. However, they were newcomers compared to one of their greatest predators, the dragonfly.

Giants Of The Paleozoic

The oldest known fossils of dragonflies date back to about 300 million years, according to a paper published by the University of California Museum of Paleontology. It is believed that dragonflies were among the first insect species to develop flight. Back then, some species of dragonfly were huge. Fossil remains have been found with wingspans of more than two feet. Scientists speculate it was the Paleozoic era’s high oxygen content that allowed dragonflies to grow to epic proportions.

Thousands Of Dragonfly Variety

Today dragonflies average two to five inches in size. The Smithsonian says there are at least 5,000 documented species of these four-winged wonders. It is believed all of them feast regularly on mosquitoes when a steady supply of the bloodsuckers is available. If not, it’s no problem for the dragonfly because they eat just about anything that flies, crawls or swims if the size is right and they can catch it.

By Land And Water

But as for mosquitos, the dragonfly assault on them is both by air and water. The dragonfly life cycle is a double whammy for the mosquito. That’s because dragonflies began their lives as underwater nymphs. The nymphs don’t have wings. Rather, they look like many other six-legged bugs that crawl around on the ground — except dragonfly nymphs keep to underwater environments. The nymphs inhabit shallow, low-flow ditches, swampy areas and ponds.

Even though they live underwater, dragonfly nymphs aren’t decked out like other aquatic bugs with paddle-like appendages for efficient swimming. But it’s no problem because they navigate their subsurface world with ease. One of their favorite foods while in the nymph stage is the larval stage of the mosquito. That means dragonflies help us out by killing millions of mosquitoes even before they get their wings.

How Many Mosquitoes?

The question is: Just how many mosquitoes do dragonflies eat? This is a difficult and complicated questions to answer. However, significant study has been done in this area by entomologists. They have been able to come up with some good data that gives some idea of how good dragonflies are at controlling the mosquito population.

One of the surest ways to get a handle on how many mosquitoes dragonflies devour is to capture our four-winged friends and dissect them to check on the content of their stomachs. Sure enough, it is common to find ingested mosquitoes inside the dragonfly gut. For the average dragonfly, it takes about 12 mosquitoes to fill its stomach. If they can get a dozen mosquitoes in their stomach at a time, how many can they eat per day?

This is not well known because there is no data on how fast their digestive system works. But some researchers feel comfortable estimating bowel at movements every three to four hours. That means dragonflies can eat 36 to 40 mosquitoes per day. This is a respectable number and has earned the dragonfly the nickname of “mosquito hawk.”

It is significant to note that a dragonfly can eat the equivalent of its own weight in 30 minutes. The man who revolutionized our understanding of the dragonfly diet was the distinguished British etymologist, Dr. Philip. S. Corbet.

Equal Opportunity Eaters

But does this mean dragonflies are always eating 40 mosquitoes per day? No, absolutely not. That’s because dragonflies are equal opportunity eaters. Again, they eat anything that they can catch — flies, gnats, potato bugs, aphids, butterflies, moths, spiders — and they are even well-known to eat bees. In fact, beekeepers report that invasions of dragonflies have sometimes devastated their hive populations. So if there is plenty of other prey easily available mosquitoes will be passed by.

Another factor that reduces the amount of mosquitoes captured is that dragonflies hunt by day while mosquitoes are more active by night. It’s a common sight to see dragonflies flitting about in the bright sunshine that most mosquitoes abhor.

While it is universally acknowledged by entomologists that dragonflies are impressive predators of mosquitoes, and that they definitely play a role in reducing their numbers, they don’t eat enough to significantly damage mosquito populations. In other words, dragonflies alone are not enough to control the problem of mosquitoes in any given location, say experts with the Orkin pest control company.

While dragonflies snatch many mosquitoes from the air, it is an almost certainty that they make a greater contribution underwater during their nymph stage. The dragonfly nymph is a voracious predator of mosquito larvae. Here again solid numbers are difficult to come by, but nymphs certainly eat tremendous numbers of mosquito larvae.

Fastest Insect On The Planet …

By the way, dragonflies have been clocked at speeds of 60 miles per hour in flight, according to Discover Wildlife. Consider that a mosquito’s top speed is a mere 1.5 mph! A common housefly is much faster, but still only has a top speed of about 35 mph. No other flying insects are a match for the dragonfly in speed.

… And The Most Efficient

Dragonflies also have another tremendous advantage over other winged insect species. Dragonflies need only flap their wings 30 times per second to achieve sizzling fast flight. Compare that to the mosquito which must beat its wings 800 times per second. A housefly beats 200 times per second while a midge needs 1,000 wing motions per second.

What this means is that dragonflies enjoy a considerable conservation of energy — energy which they can devote to flying and hunting. By the way, dragonflies have a very efficient method for catching mosquitoes. They form a “basket” with their legs to easily pluck even fast-moving prey out of midair. That doesn’t stop them from grabbing a frequent snack from the ground, however. They prey upon ants, termites and other crawling bugs and worms.

For some 300 millions years — and counting — dragonflies have been one of Mother Nature’s most efficient killing machines. Thankfully, they love to kill and eat mosquitoes.

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