What's The Deal With Those Giant Swarms Of Dragonflies?

By Melissa McEwen in News on Aug 5, 2015 2:10PM



(Jan Crites from the Chicagoist Flickr Pool)

If you've spent any time outside this past week, you may have noticed giant swarms of large dragonflies. These are a common species known as the green darner, and they are busy using their impressive eyesight and flying skills to hunt down mosquitos and flies.

As it turns out, the number green darner dragonflies has exploded this year, according to Doug Taron, Curator of Biology at Peggy Notebaert Nature Museum.

"The population of green darner dragonflies really boomed—there may be a number of things contributing. One of them is the large number of mosquitoes," he said.

Mosquitos, like dragonflies, have aquatic larvae, so the dragonflies eat them both as swimming youngsters and ace flyer adults.

The green darner is one of the most commonly seen dragonflies, but their habits remain mysterious. They live up to six months as adults and are capable of migrating large distances.

"No one really knows where they go," Taron told Chicagoist. "Swarms show up later in the Gulf Coast, but it's not known if they are the same dragonflies."

While the swarms may seem overwhelming, Taron says "people should know they aren't harmful to them—they don't bite or sting people."

If you want to watch big displays, Taron advises heading to the lakefront. Photographers who want to snap a shot of them resting might be able to get one early in the morning or later in the afternoon. And you may also see birds eager to enjoy a dragonfly snack.

Green darners are just one of 98 recorded species of dragonflies living in Illinois, including the critically endangered Hine's emerald.

If you're serious about spotting dragonflies, head to your closest park with a pond or stream.