We’ve all had a dragon or damselfly land on our rod or cane pole while fishing. As a kid, I liked to think it was good luck. When action was slow, I’d delay the next cast just to watch their antics. You may have seen a small bass leap into the air trying to catch one hovering over the surface. Turns out, these fascinating critters have been an attraction to Nature’s landscape for millions of years.
Adult dragonflies are characterized by large multi-faceted eyes, two pairs of strong, transparent wings sometimes with colored patches, and an elongated body. Hind wings are broader than forewings. Dragonflies can be mistaken for damsels since they are similar in structure, though usually lighter in build. At rest, most dragonfly wings are held flat and away from the body. Damselflies hold wings folded along or above the abdomen. Dragonflies are agile fliers, while damselflies have a weaker, fluttery flight. Many dragonflies have brilliant iridescent or metallic colors produced by structural coloration that make them conspicuous in flight.
Fossils of very large dragonfly ancestors were found in rocks dating back 325 million years. Some had wingspans up to 30-inches. Dragonflies are predators in aquatic larval stage as nymphs and as adults. Nymphs feed on a range of freshwater invertebrates. Larger ones can prey on tadpoles and small fish. Adults capture insect prey in the air, making use of their acute vision and highly controlled flight. Several years are spent as nymphs living in fresh water. Adults may be on the wing for just a few days or weeks. They are fast, agile fliers, sometimes migrating across oceans and often found near water. Dragonflies are on every continent except Antarctica. In contrast, damselflies tend to have restricted distributions across continents. Dragonflies have been observed around desert pools on the Mojave Desert. They can be seen from sea level up mountains. Species diversify with altitude. Their altitudinal limit is about 3,700 meters.
Adult males are territorial and vigorously defend areas near water with a good view over insect-rich feeding grounds. Such zones provide suitable habitat for larvae to develop and females to lay eggs. Large flocks of feeding adults gather to forage on swarming prey such as emerging flying ants or termites. Defending a breeding territory is fairly common among male dragonflies, especially among species that congregate around ponds in large numbers. The territory may contain desirable features such as sunlit stretches of shallow water, a special plant species, or particular resource necessary for egg-laying. The territory may be small or large, depending on quality, time of day, and number of competitors. It may be held for a few minutes or several hours.
Larval dragonfly stages last up to five-years in large species or between two months and three years in smaller species. When nymphs are ready to metamorphose into adults, they stop feeding and make their way to the surface, generally at night. They remain stationary with their head out of the water, while the respiration system adapts to breathing air. They then climb up a reed or other emergent plant and molt. Anchoring itself firmly in a vertical position with its claws, skin begins to split at a weak spot behind the head. The adult dragonfly crawls out of its larval skin and the exoskeleton hardens. Adults hunt on the wing using exceptionally acute eyesight and strong, agile flight. They are almost exclusively carnivorous, eating a wide variety of insects ranging from small midges and mosquitoes to butterflies, moths, damselflies, and smaller dragonflies. A dragonfly may consume as much as a fifth of its body weight per day.
Damselflies are smaller, have slimmer bodies, and most species fold their wings along the body when at rest. They’re also an ancient species and found on every continent except Antarctica. Like dragonflies, damselflies are predatory and mature through similar metamorphic stages. Their presence on a body of water indicates that it is relatively unpolluted. However, their dependence on freshwater makes them vulnerable to damage of favored wetland habitats. Nymphs develop through about a dozen molts as they grow. In later stages, wing pads become visible. When fully developed, nymphs climb out of the water and take up a firm stance, the skin on the thorax splits and the adult form wriggles out. Most damselflies emerge within a few hours during cool, daytime conditions. On a hot day, the cuticle hardens rapidly and the adult can be flying away within half an hour
If you have observed a large number of shell casings around a dock or shoreline area, now you know the source. You just missed a dragonfly / damselfly hatch.