Did you know that dragonflies spend most of their lives underwater? The creature in the photo is a dragonfly nymph—the juvenile stage of this familiar insect. Long before they dart above lakes and wetlands, dragonflies live underwater for months, molting through several stages. As nymphs, they are formidable predators, using a specialized jaw to catch other aquatic invertebrates and even small fish. Once they emerge and transform into adults, their brief life above water is focused on eating, mating, and laying eggs to begin the cycle again.
Dragonflies are not just fascinating—they’re also incredibly useful. As adults, they continue their predatory lifestyle in the air, hunting with exceptional speed and agility. A single dragonfly can eat hundreds of flying insects in a day, including mosquitoes and black flies. This natural pest control makes them a welcome sight near during the summer months.
Dragonfly nymphs are part of a larger group of organisms known as macroinvertebrates—small animals without backbones that are large enough to see without a microscope. This group includes insects like mayflies, caddisflies, and midges, as well as snails, worms, and crayfish. These organisms are a vital link in the aquatic food chain and help cycle nutrients throughout the ecosystem. You’ll often find them clinging to rocks, vegetation, or buried in the sediment of lakes and streams.
Macroinvertebrates are more than just residents of our waterways—they’re also bioindicators of water quality. Because they spend most or all of their lives in water and have varying levels of tolerance to pollution, their presence (or absence) can tell us a lot about long-term environmental conditions. Unlike water samples, which provide only a snapshot of quality at a single moment, macroinvertebrates reflect the cumulative health of water over weeks or months. So next time you see a dragonfly, take a moment to appreciate not just its beauty, but the story it tells about the waters it came from.
