Dragonfly numbers build this time of the year. Many can be seen flying over lawns and fields. They are interesting insects who have been able to survive changing environments for over 320 million years.
Several groups and species of dragonflies occur with different color variations within each group.
Unlike moths and butterflies which go through what is called a complete metamorphosis (eggs, larvae, pupae and completely formed adult), the dragonfly goes through only three stages making its metamorphosis incomplete.
From an egg the dragonfly hatches into a nymph. The nymph grows and molts its skin several times. Finally the adult dragonfly emerges as the nymph's skin splits one last time.
The dragonfly's life cycle resembles an amphibian's. As an adult the dragonfly lives in the air with all the necessary equipment for an aerial existence, but, like an amphibian, it must return to the water to lay its eggs. The young nymphs that hatch from the eggs are only suited for an aquatic existence.
The nymph doesn't look any more like an adult dragonfly than a tadpole looks like a frog. But instead of growing adult equipment a little at a time as the tadpole does, the nymph grows into a bigger and bigger nymph with the adult dragonfly evolving inside the nymph's skin.
The final molt brings the aquatic nymph out of the water, where its split skin reveals the fully formed adult.
Both the aquatic nymph form and the aerial form of this creature have one thing in common - a voracious appetite for other insects.
In the nymph form the dragonfly is an ugly brown creature that lurks in the dark places of a pond or slow-moving stream. If you look into the water you may spot this nymph, but the brown color serves as excellent camouflage.
When an unsuspecting insect or even a small fish or tadpole swims too close, the dragonfly nymph extends a long, jointed lower jaw, which is equipped with grappling hooks, and snatches its prey.
The adult dragonfly doesn't wait in ambush. It pursues its prey of mosquitoes and small insects aggressively. It catches this prey in mid-flight with its legs which have stiff bristles.
The reason dragonfly populations are currently growing is due to migration. This time of year migrating dragonflies begin heading south to avoid cold weather.
Little is known about this migration pattern because they are hard to trace. They use the same flyways as migrating song birds and hawks. Birders watching for hawks during migration observe dragonflies going over in large numbers.
Offspring of these dragonflies will come through in the spring heading north.