Written on ancient maps as warnings to mariners, Here be Dragons conjured up images of fire-breathing monsters lurking in unknown regions of the world ready to incinerate the unwary.
Here be Dragonflies is not a warning, but instead an invitation to head down to our local lakes and ponds to see these intricate and beautiful creatures that are just now taking to the air as the full heat of summer has arrived. Not scary, and not fire-breathing, dragonflies compete with butterflies as one of the top insect attractions in our parks and gardens.
Whenever I watch dragonflies, I’m always awed by the thought that these insects are the modern descendants of a fantastically ancient lineage. Fossil dragonflies, very similar to those we see today, were flying around almost 300 million years ago. That’s a staggeringly long time ago. As a comparison, the last Ice Age ended about 10, 000 years ago. Dragonflies have been around about 30, 000 times longer. Few animals living today have remained essentially unchanged for such a long stretch of geological time. When dragonflies were darting around the giant forests of the Carboniferous Period, mammals had not yet even appeared on earth. A very successful evolutionary “design” indeed.
Below is a second common Burnaby dragonfly – the blue dasher. What a great name! No doubt why it’s called blue, and it is pretty zippy in flight too. However, this dragonfly’s wings are not boldly marked like the eight-spotted. However, look at the rakish angle they are held in contrast to the more conventional stance of the eight-spottted.
Climate Change Connection
The blue dasher is found only in the most southerly areas of Canada; however it is a species that is likely responding to global warming. It has extended its range northward in recent years, and continues to do so. Not one of the dramatic signals that things are changing rapidly on the planet, but nonetheless, a signal from nature that they are.
Dragonflies mostly feed on flying insects, sometimes even other, smaller dragonflies. To see, pursue, and capture their fast-moving prey they need fantastically sharp vision. The two large compound eyes which take up a large proportion of their head have evolved to capture even the slightest movement. Made up of up to 30, 000 individual simple eyes, the compound eyes of dragonflies not only give very fine detection of movement, but because in some species they form an almost spherical array around the head, they give a field of view approaching 360 degrees. Click the image of the blue dasher above to get a close look at its stunning turquoise eyes.
No doubt part of the evolutionary success of dragonflies can be attributed to their wings. The intricate pattern of veins (venation) which carries blood to the wings also provides structural strength for powerful wing beats. Coupling this with the ability to flap and rotate all four wings independently, makes dragonflies incredibly manoeuvrable fliers. They can hover, rotate on a dime, make rapid vertical climbs and descents, and maintain forward flight at high speeds, and even fly backwards, all the time keeping the body horizontal.
Much smaller than their larger and more aggressive cousins, damselflies are also emerging in numbers and flying around the water’s edge at our local lakes and ponds. Slower moving than dragonflies, they hunt mostly by gleaning insects (aphids) hiding in the waterside vegetation. Damselflies are distinguished from dragonflies by the way they generally hold their wings closed over their bodies. The males, and some females, are mostly eye-catchingly blue, like tiny electric-blue pencils floating in the air on almost invisible wings. To many people damselflies are known as bluets, which is an entirely appropriate name. Bluet is also frequently seen as part of the common name for a number of species of damselflies.
Much more difficult to identify than some dragonflies, many species of damselflies look superficially similar. The one I photographed below is, I think, a tule bluet – a common species hereabouts. However, birds are where I’m confident in my identifications; I’m far less certain when it comes to damselflies. Please correct me if I’ve made a misidentification.
So whether it’s dragonflies or damselflies that catch your fancy, it’s time to take a look because Here (they) be….
And take your binoculars and camera. Close-ups are definitely in order when viewing these beauties.
If you’re interested to learn more about our local dragonflies, I suggest Dennis Paulson’s Dragonflies and Damselflies of the West. It’s also available in Burnaby libraries. I consulted the book extensively for this post.