Late summer is Dragonfly season in Terra Firma’s fields. Every day around sunset, thousands of them take to the air en masse, hovering and swooping over our tomato, melon and other fields. I enjoy watching them, but until recently I had never given any thought to what they were doing.
I’ve always known that immature dragonflies, which live in water, were carnivorous. But I hadn’t known that their primary source of food is mosquito larvae. In this capacity, they perform an invaluable service to humanity.
Meanwhile, I had always thought of the beautiful, graceful adults as benign and friendly. Many “beneficial” insects eat other bugs only when they are immature: once they become adults they spend all their time mating and then die. Not dragonflies.
It turns out that the adults are also ravenous eaters, feasting on small flying insects like mosquitos but other, larger pests as well. Eating hundreds of bugs every night each, they are one of nature’s most dangerous predators, possessing a suite of almost unbelievable abilities. They are lightning fast with incredible vision, which explains why you can walk through a swarm of them and never have one hit you. I’ve also never seen one hit the windshield of a car.
While the adults are flying and eating, they are also mating — in the air. The females then fly a short distance to a calm body of water, like the pond or drainage ditch on our farm, and lay the eggs of next year’s crop of dragonflies. As our harvest of summer vegetables wraps up and the fields are mowed and plowed under to make room for winter crops, the dragonflies will disappear along with their pesky and obnoxious food sources. Until next spring, when the eggs will hatch and the nymphs will start eating again.