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Abundant Dragonflies

Published on: Sep. 17, 2010

dragonfly on flowers of blazing star

Have you seen large numbers of dragonflies in recent weeks? I’ve had contacts from Missourians in several locales reporting the noticeable massing of dragonflies.

There are a couple of reasons dragonflies will congregate. They are predatory on small, flying insects and will gather in large numbers for feeding where their food supply is plentiful. This often takes the insects to feeding locations away from streams or ponds, and people are sometimes surprised to see them away from water. While tied to water for egg-laying and nymph development, flying adults will visit many habitats far removed from water. Some species of dragonflies migrate in late summer and fall and will gather into larger swarms for long-distance migration. It is hard to make general statements about dragonflies because Missouri has more than 80 species and their behavior varies. Some species don’t migrate, while others do. One species, the green darner, has a resident population as well as a migratory one.

Studies of dragonfly migration, using tiny radio transmitters on the insects, have indicated similarities to bird migrations. They tend to migrate in response to cooler, nighttime temperatures and will take advantage of northwest winds associated with cold fronts. Movement is not continuous, with flight days interrupted by days of rest and feeding. The destination of the southward-moving insects ranges from peninsular Florida to Central America. American kestrels’ migration is often concurrent with dragonfly migration and the small falcons will feed on the insects as both groups move south. Fall-migrating dragonflies only make a one-way trip. Those that come north in spring are adult insects of the next generation, originating from eggs laid in southern waters.

perched dragonfly over water

I find that dragonflies are like many other biological groups of which I have limited knowledge. With a little investigation, I find that there’s much more diversity and fascinating behavior in the group than I might have expected. Surprising interactions with other species reinforce the picture of the ecosystem as a functioning whole composed of many interconnected parts.

Comments

On September 23rd, 2010 at 3:25pm chris deeken golden eagle il said:

Have noticed large swarms for last 3 weeks they love when im cuttting the yard the buffet is open then

On September 17th, 2010 at 9:34pm Rebecca Warden said:

Today I had a large swarm of dragonflies in my backyard near Chesapeake, Mo about 30 minutes before sundown. They were feeding on nats or mosquitos and I could actually see them catching them within 5 feet of me in the sunbeams. It was fascinating to watch.

On September 17th, 2010 at 9:32pm Rebecca Warden said:

I had a large swarm of dragonflies this afternoon in my backyard near Chesapeake, MO. The sun was about 30 minutes from going down and I could see the swarm of mesquitos or nats they were feeding on in the sunbeams through the trees. It was fascinating to watch and I was thrilled to see the bugs being eaten. I have had an major problem with mesquitos since the recent rains. Thank you for having this in your magazine.

On September 17th, 2010 at 3:46pm Ruth Forester said:

Interesting! This explains something I witnessed a short time ago. At a farm between Aurora and Mt. Vernon, Lawrence Co., Mo. I noticed swarms of insects and asked what they were. I was told that they were dragonflies. They were seen swarming in places about the place where you would not expect to see them, away from water sources. Thanks!
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