Dragonflies and Damselflies

Striped Meadowhawk Dragonfly

Spend any fishing during the summer and you will see them—flitting by, hovering over the water's surface, or perched on a twig in the sun. As colorful, predatory acrobats of the insect world, dragonflies are beautiful insects and fascinating if you make the effort to know them. They are known by several colloquial names, such as the devil's darning needle or snake doctor, and have been the subject of myth down through the ages.


Dragonflies' biology and behavior is as varied as their size, shape and color. About 5,000 species are known to exist world-wide. They range from sea-level to mountain top, from the Arctic Circle to the equator and beyond. All have six legs, two pair of wings and a body divided into head, thorax and abdomen. The head anchors two large compound eyes that don't miss anything! While there are thousands of species, with a good photographic, site-specific guidebook and a pair of close-focusing binoculars, most species can be distinguished from one another in the field. Many people keep a list of dragonfly species they have seen, just as they do for birds.

Dragonflies and their close relatives, the damselflies, have been flying around for about 300 million years, long before any bird took wing. And some of those early dragonflies were as large as birds, with wing-spans of nearly three feet! Being such "primitive" insects means they haven't changed much over time; their basic body design was equally successful during the age of the dinosaurs through the ice ages to today. But, thankfully, they are smaller now, with the largest species having wingspans of about four inches (imagine trying to catch a three-footer in your butterfly net!).

 

Where do dragonflies come from? Read on. 

Common Green Darners

Life Cycle

Dragonflies begin their life in the water as wingless aquatic larvae, or nymphs, whose gills for extracting oxygen from the water are located in their rectum. Expelling water from their rectum in a sudden burst acts as a sort of jet-propulsion and allows the larvae to escape predators, such as fish. The larvae are veracious predators themselves, eating other insects—including their own kind—small fish, and about any other animal small enough for them to control. They have a long hinged jaw, which folds beneath their body and can be extended instantaneously to grasp prey (think Alien!). Maturing, they pass through several stages, or instars, shedding their skin with each to grow successively larger. After a few months or a few years (many overwinter under frozen lakes and streams) the final in-star climbs out of the water to transition to adult life. Its skin splits open along its back; the adult squeezes out, hanging upside down by its abdomen; an acrobatic move brings it upright, holding on by its legs; fluid is pumped rapidly into the wings causing them to expand; and after a few hours this pale, soft-winged version of an adult is ready to take its maiden flight.

Much of a dragonfly's time is devoted to breeding, and here is where we see some of the most interesting behavior. Males, more brightly colored than the females, stake out small territories where the water is suitable for the females to deposit their eggs. Some species patrol their territory in flight, while others will perch and fly only when a female or rival male appears; rivals are chased away. Females are definitely not courted, but some manage to escape the advances of the male. If mating is to occur, the male takes physical hold of the female in flight, clasping the back of her head with special appendages on the end of his abdomen. This is referred to as flying in tandem. While still in flight, or perched, the female reaches forward with her appendages and takes the males' sperm from an area under the forward part of his abdomen where he previously placed it (sperm originates at the tip of his abdomen). Pairs can fly well in tandem and fairly well even with the female reaching forward, which is known as the wheel, or heart, position. After the females' eggs are fertilized, the male, depending on species, will remain attached while she releases her eggs, or possibly hover nearby, guarding her from other males. Many females "broadcast" their eggs on the surface of the water with a touch of the abdomen, but the darners insert their eggs into plant tissue just under the water surface. The broadcast method may attract a school of hungry minnows, while the latter method is safer from egg predators. Female darners can become nearly submerged during egg-laying, with the attached male helping to extract her from the water. The clubtails, many species of which inhabit streams, often lay their eggs in muddy or sandy substrate at the edge of the water so the current will not carry the eggs away. Adults may breed several times a year, the females' wings becoming tattered in the process. If lucky, adults may live a few months, mating multiple times. But some darners extend the breeding season by migrating north or south.

 

To learn about dragonflies at Columbia, read on. 

Band-winged Meadowhawk Dragonfly

A Dragonfly's Life at Columbia

With four wings that operate independently, adults can fly forward, backward, upside-down, hoover and make the most amazing maneuvers (just try catching one). They take most of their prey on the wing, catching them with their legs arranged as a net. Small meals, such as mosquitos, can be eaten on the wing, while larger prey is consumed from a perch, or even from the ground (as is the case with many of the clubtails). When in the feeding mode dragonflies can be seen far from water, pursuing flying insects, including lacewings, flies, butterflies, beetles and smaller species of their own kind. In turn, they are eaten by a variety of predators, including birds, frogs, spiders, robber flies and praying mantises. When emerging from the water, they are particularly vulnerable and may also be taken by blackbirds, raccoons and other mammalian predators.

Here, at Columbia National Wildlife Refuge, are about 28 species of dragonflies and 14 damselflies, according to a Grant County list. One of the most abundant is the California darner, a spring flier. The darners are large and have a relatively long abdomen, so they perch with their abdomen hanging down. Smaller dragonflies, such as the equally abundant blue dasher, a summer flier in the skimmer family, can perch horizontally and hold their abdomen straight out behind. The meadowhawks can be challenging to identify, coming in various patterns of red, and tend to be autumn fliers. The river jewelwing is a large, metallic damselfly that can be seen around Crab Creek; the emerald spreadwing is another beautiful damsel. All are worth taking a closer look at and can be slowly approached for observation or a photograph. So, when the fish aren't biting, don't overlook these tiny terrors of the insect world!

 

And don't for get to check out our Dragonfly Photo Gallery.