So far this has been a disappointing summer weather-wise. In my part of the world it has been cooler and wetter than normal?or at least what we’ve come to regard as normal. Yet the conditions must have been just right for dragonflies, for they are everywhere.
Not since I was a young girl do I remember seeing so many. The fascination with their size and lovely iridescent colour is as keen today as it was then. As a kid I remember trying, usually unsuccessfully, to catch them; they were too fast, too elusive. Despite their huge size and noisy flight, I wasn’t afraid of them. Unlike the horseflies of my youth, they didn’t bite or sting. They were simply pretty flying novelties.
Turning to my Lone Pine field guide Bugs of Alberta and the Internet for more information has been like sitting in a science class?except that I wanted to be there! Now that I know that these lovely little creatures are voracious and efficient hunters of insects, including mosquitoes, they are number one in my books. That may also explain why there are so many dragonflies; the bumper crop of mosquitoes assures quick and easy meals, just what the on-the-go dragonfly demands.
I also now know why It’s impossible to sneak up on a resting dragonfly. They have huge compound eyes (made up of about 30,000 ommatidia or individual eyes) with a full 360-degree range of vision. They can see you coming or going. Their vision itself isn’t that great; it’s more of a motion detection thing. The flattened front of the eye, with its concentration of eye cells, allows them to spot prey on the fly.
Speaking of flight, dragonflies are fast; one in Australia was clocked at 36 miles per hour. They can fly backward, forward, and sideways, and can hover like hummingbirds. Their two pairs of large, strong wings are designed to catch the slightest breeze and require a minimum of effort: only thirty beats per second compared to the hundreds of beats required by a housefly.
The only dragonflies I can differentiate are the super-sized blue ones and the smaller orange ones, even though my bug guide mentions over 50 species in Alberta. Colours include blue, green, black, brown, red, orange, and yellow in varying combinations. Fossils of prehistoric dragonflies indicate a wingspan of 28 inches! Of the five thousand varieties in the world today, some have a wingspan of seven inches.
Most of a dragonfly’s lifespan is spent as a nymph. Some varieties are in a nymph state for up to four years before emerging from the water body where they hatched. They are weak and vulnerable for a short time while their new wings dry. Most dragonflies will live from two months to up to one year, depending on climate.
What fun it is to learn for the sake of learning rather than to pass a quiz! Just imagine the world if we all knew more about the miracle of our creature companions, from where I sit.
