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Dragonflies and damselflies at the FWG
Most nature enthusiasts are aware of the odonates (damselflies and dragonflies). Even those who know them only from cottages or camping recognize that not only are they beautiful, but they are also welcome predators, consuming 1000s of blackflies, deerflies, and mosquitoes (i.e., all the "nasties" who prey on us!) during their short but amazing lives.
However, not many people know that there are 511 different species in North America, including approximately 163 in Ontario — 120 occur in the Ottawa-Hull area (within 50 km of the Peace Tower)! Until very recently, only highly technical and rather intimidating scientific publications were available for learning about these insects, but thanks to an increased interest especially among bird-watchers, a few more user-friendly field guides are finally coming off the presses.
Odonates belong to an ancient order of insects that is at least 300 million years old. And their life cycle gives us many clues as to how they managed to persist (with very few changes over the millennia) for so long. They were built for survival!
Odonate eggs are laid in aquatic environments such as ponds, lakes, and rivers (most species prefer specific habitats). They hatch into larvae commonly called "nymphs" — a deceptively pretty name for what are truly bizarre-looking crawling creatures with voracious appetites and hunting techniques that would rival those of "Jaws." After several weeks to several months of preying on tadpoles, insect larvae, and sometimes each other, the odonate nymphs eventually crawl out of the water, breathe air, and the adults emerge. The emergence is a spectacular event for those lucky enough to observe it. The young adult, called a "teneral," bursts through the back of the nymphal skin and pulls itself out. Once its wings and body are fully expanded, dried, and hardened, the teneral begins its life in flight.
And what a life! Most odonate species live for only a few weeks, but their lives are full of experiences that might make many humans envious: long-distance travel, aerial hunting and territorial battles, high-tech body designs (including nearly 360 vision and the ability to fly both forward and backward at high speeds), and lots of very acrobatic sex. During mating, the male uses claspers at the end of his abdomen to grasp the female behind her head. If she accepts him, she bends her own abdomen around so that her vulvar plates meet his secondary genitalia, which are located near the underside of his thorax — and a heart-shaped "flying wheel" is created. With her sharp ovipositor, the female deposits her eggs into moist soil, aquatic vegetation, or directly into the water... and the life cycle begins again.
Although all odonates lead similar lives, the diversity of families, genera, and species within the order is remarkable in terms of appearance and behaviour. Many of our common damselflies and dragonflies can be easy to identify, even through binoculars or with the naked eye. But most can only be learned through capture and close examination of the various colour patterns and the genitalia. It is not necessary to harm them, but it sure can be a lot of fun trying to capture them, and it's always awesome to get up-close and personal with these winged wonders!
Damselflies (suborder Zygoptera) are generally small and delicate, with widely separated eyes and wings that are usually held together above the thorax. Weak fliers compared to dragonflies, they are often found hiding among vegetation or flying low over ponds and streams. Some of the common damselflies that may be found at the FWG are:
Dragonflies (suborder Anisoptera) are generally more robust, although some species may be nearly as small as damselflies. Some families have eyes that join, others have separated eyes, but all anisopterans hold their wings out at right-angles to the thorax, like miniature airplanes — and they can fly like jet-fighters! A few species that are very common in Ottawa and may be seen at the FWG are:
Good references for beginners