By Rick Borchelt
These are the hot, hazy days of summer’s end when the meteorological season finally catches up with the astronomically long days of June and July. All summer, the larvae of midges and mosquitoes have been gorging on the algae soup in our still, warm ponds and slow-moving streams. The caterpillars of small moths and butterflies have been fattening themselves on the rank growth of forests and meadows. And now summer’s dragons are on the hunt for them all.
Summer has dragons? Indeed! Not the fearsome, venom-spewing mythological nemesis St. George fought, of course, but one equally fierce, for all their smaller size —dragonflies. These aeronautic wizards outperform the most daring “Top Gun” stunts, appearing out of nowhere and vanishing just as quickly as they relentlessly patrol creeksides, lake margins and meadows, terrorizing other winged creatures their size or smaller.
Dragonflies are members of the insect order Odonata — from the Greek for tooth or toothed, a nod to their formidable jaws. The order also includes the dainty but no less vicious damselflies, predators we’ll talk about in a future column.
August is the peak season for seeing dragonflies chasing down prey in our area. Look for them in your yard or garden and flitting close to most any body of water: Lake Artemesia, along Paint Branch Creek, Indian Creek or Northeast Branch, and around Sentinel Swamp Sanctuary, the pond between Columbia Avenue and the College Park Metro station. Without much effort, we can easily find a good 10 types of dragonflies here, including the common green darner, Eastern pondhawk, wandering glider, common whitetail, blue dasher, Eastern amberwing, Halloween pennant, spangled skimmer, and black and Carolina saddlebags among them. The names alone are incentive enough to study dragonflies!
The dragonflies we see on the wing are the culmination of months or even years of aquatic life. Just as the cicadas we now hear droning in the trees spent years underground, dragonfly nymphs spend much of their lives in the water — from a few months to as many as five years. They are no less fierce than the adults. Nymphs have a hinged jaw that, like the monster of the “Alien” movie franchise, shoots out and grabs its prey —tadpoles, small fish, other aquatic insects, even other dragonflies —then pulls it back to its mouth to feed. At the appointed time, usually at night or in the early morning, the matured nymph hauls onto a stalk or branch above the water and sheds its skin for the final time, revealing itself as a lethal aerial powerhouse.
Mating for dragonflies is a complicated business — and for the female a sometimes fatal one. The males of many species have specialized hooks on the tip of their abdomens perfect for grabbing the female dragonfly by the back of the head, often puncturing her eyes or head in the process. Seemingly unperturbed, from her trapped position, the female then curls her abdomen underneath his to pick up packets of sperm. The males of some dragonfly species will then carry the female, still dangling from his claspers, and dip the end of her abdomen in the water while she drops her eggs.
Dragonflies are best known for their impressive compound eyes (huge when they aren’t punctured during mating) with tens of thousands of individual facets. This arrangement gives them an incredible ability to detect motion and an almost spherical view of the world around them. The compound eyes provide an incredible advantage when snagging smaller, slower flying insects that pass by and serve as an efficient defense mechanism, too. Dragonfly collectors know that they are the hardest insects to capture, and I’ve personally ended up many times dunked in a creek or pond after a failed swing of the net!
Monarchs get all the attention for their migrations, but many kinds of dragonflies are long-distance travelers, too. Our common green darners show up here in early spring, having hatched in Mexican, Caribbean or southern U.S. waters. The nymphs of these spring migrants eventually emerge as adults, and will heed some environmental cue to fly south, where they lay eggs that mature into a non-migratory generation. These stay-at-home dragonflies lay eggs that will mature and fly north to complete the cycle. Many other dragonfly species migrate as well.
One other such migrant is one you’re likely to see this time of year are the dragonflies buzzing around your car as you idle at a stoplight. These light brown insects are one of two glider dragonflies: wandering or spot-winged gliders. They sometimes confuse the light reflected off of car windshields for reflections on water and think your car may be a spot for egg-laying.
College Park has a special place in dragonfly hunters’ hearts; the piedmont clubtail dragonfly was first described here, in 1917, from a specimen collected by USDA researcher Bertha P. Currie from marshy fields near the Lakeland neighborhood. The piedmont clubtail is common in some parts of the southern U.S., but it has been wiped out in Maryland, a victim of draining marshes and meandering river watercourses for development.
Have questions for Rick about the world of nature in and around the city, or suggestions for future ”College Park Wild” columns? Drop him a note at firstname.lastname@example.org.