The Incredible Dragonfly
There is something magical about dragonflies. Evolving some 300 million years ago – long before dinosaurs – dragonflies were one of the first winged insects to inhabit the Earth. Five to 12 centimeters is their typical wingspan today, but fossil records show specimens with wingspans up to 60 cm! Some scientists speculate that high oxygen levels during the Paleozoic era allowed them to reach their enormous size.
There are more than 5,000 known species of dragonflies, with about 130 residing in Ontario. They are most often seen flying around water bodies, particularly ponds, as their nymphs (young dragonflies, also known as larvae) live in fresh water. Their habitat varies according to the species, though, and some dragonflies are found in dry meadows, only returning to wetlands to lay their eggs.
Like Monarch butterflies, dragonflies will migrate with the changing seasons. Some species fly solo, while others travel in swarms. Dragonflies can be recognized by their long, needle-like bodies with two pairs of transparent wings, and come in many colours, including red, brown, blue and gold. They belong to the order Odonata, an ancient Greek word for 鈥渢ooth鈥�, describing their serrated mandibles (jaws) that they use for catching and eating prey.
Twelve Spotted Skimmer
Dragonflies are not born to fly, but rather they are born to swim. Eggs are laid in still water or on aquatic vegetation, where they hatch and the larvae emerge as an aquatic insect. These nymphs can spend two to four years in the water and molt (shed their skin) several times before they transition to the next stage of their life. Through a process called incomplete metamorphosis, they evolve straight from a nymph to an adult. As they crawl out of the water for their final molt, the nymph鈥檚 skin splits open and the adult dragonfly emerges. After a short rest, it is ready to take to the air.
Dragonflies are an essential part of freshwater ecosystems. In the middle of the food chain, they both regulate insect populations and provide important food to predators. Able to snag prey at lightning speed, the nymphs are prolific hunters and feed on insect larvae, tadpoles, small fish and other aquatic creatures. As adults, they catch insects, such as mosquitoes, midges, moths and flies, with calculated aerial ambushes. While flying, they can snare insects with their feet or pluck them out of the air with their jaws and consume them in flight. In turn, dragonflies are food for several species of fish, frogs, turtles, birds, and mammals.
Dragonflies鈥� unique, two-winged design makes them incredibly agile in the air and few in the animal kingdom can compare to their flying ability. They are considered the fastest insect, being clocked at speeds of over 50 km/hour. They can fly in any direction (including straight up and down, sideways and backwards), hover in place, and make 360 degree turns. Their giant compound eyes, which contain nearly 30,000 lenses, cover the entire head, providing them with nearly 360-degree vision. This finely tuned eyesight brings them continuous information about their surroundings. Due to their amazing abilities, they have inspired new technology, from drones and robots to artificial visual systems.
Widow Skimmer
Dragonflies鈥� outstanding vision and flying skills contribute to their success as predators. They can spot and adjust their flight to intercept unsuspecting prey from any direction and a single dragonfly can eat 30 to 100 mosquitoes and biting flies in a day. They are so efficient in hunting that they have a 95% success rate (compared to lions at 25%), making them the most remarkable predators on the planet.
Thankfully, dragonflies are docile around people and do not bite or sting. In fact, if one lands on you, it is considered a sign of good luck. The next time you are near a wetland, you may want to become a dragonfly enthusiast and spend time watching these colourful insects, a hobby known as oding.
Contact: Brenda Gallagher