By Tina Symko and Dan White
Whistler Naturalists
Last summer, my boyfriend and I swam at Lost Lake nearly every day after work. We’d often end up staying for hours, enjoying the warmth of the evening sunshine and the beauty of the mountains around us. One evening in particular, when it seemed like it just couldn’t get any better than swimming in a fresh mountain lake at sunset – ZOOOOOOM! What the heck? Ooooh, a dragonfly!
The dragonfly circled above us as we swam, looking so amazing with its shiny blue-green translucent wings. I watched in awe as the dragonfly zoomed over Dan and landed on his head for a quick second before it flew away across the lake. "WOW! It’s good luck for the rest of your life if a dragonfly lands on you!" I exclaimed.
I had no idea that dragonflies are among the most ancient of living creatures. Did you know that dragonflies pre-date dinosaurs by 100 million years? As other species disappeared from the earth in a series of extinctions, these predators thrived – imagine prehistoric dragonflies with wingspans of up to 70 centimetres!
Today there are few places in the world where you can’t find at least one of the 5,000 species of Odonata, which includes damselflies (Zygoptera) and dragonflies (Anisoptera).
The dragonfly life cycle may be complete in a year or two, but can take as long as four years, making dragonflies one of the longest-living species of insect, as well as the largest.
Dragonflies lay their eggs on the surface of the water, on floating vegetation or on sand or mud bottoms. The dragonfly larvae spend 2 to 5 years underwater. During that time they hunt insects, tadpoles, and small fish for food. Eventually, nymphs will emerge from the water during the first warm days of spring and transform into winged adult dragonflies. As young dragonflies mature, their wings acquire their beautiful shimmering colours.
Actually, it is the shell of their wings that scatter the light, colouring the wings in the same way that rainbows are formed. The dazzling winged predators that we see during summer represent only the final few weeks of a lifetime. Fully mature, the dragonfly returns to the water to breed and the cycle begins anew.
Large wings and other physical characteristics make them superb aerial predators. Dragonflies can fly up to 50 km per hour and stop on a dime. A slow wing beat-rate results in a relatively quiet buzzing noise to give the dragonfly a great hunting advantage. Because its forelegs are directly under its head, a dragonfly can pass its captured prey to its mouth with ease and eat literally on the fly!
Dragonflies can be seen in the summertime by lakes, rivers, streams and wetlands and they play a critical role in wetland ecology. The larvae are food for young fish, and the tender bodies of the newly hatched adults provide tasty snacks for frogs and song birds. Dragonflies also feed on other insects — in several hours an adult dragonfly can consume its own weight in mosquitoes.
For that reason they’ve become very popular with the recent spread of West Nile virus — some B.C. parks even purchase dragonflies to help control mosquito populations.
Dragonflies, along with damselflies and butterflies, are among the most threatened species of insects globally. It is estimated that about 15 per cent of North American dragonflies are at risk of extinction as dragonflies’ aquatic habitats have been heavily impacted over the last 100 years.
Wetland habitat decreases as areas become developed and stream habitats become degraded, threatening some of the world’s most beautiful and ancient species. When you see a dragonfly showing off its aerial wizardry in catching mosquitoes in mid-air, remember that for most of its life, it was an important part of the aquatic ecosystem — we need healthy streams and wetlands to help dragonflies last forever.
Upcoming Events
Dragonflies and Birds Nature Walk, 6:30 p.m. Wednesday, July 6 th . Join visiting dragonfly and bird guru Derrick Marven in an evening walk along the Valley Trail. Meet at the base of Lorimer Road, by the Catholic Church.
The Whistler Naturalists Society monthly birdwalk will be held on Saturday, July 2, 2005. We start at 7:00 a.m. at the west end of Lorimer Road near the entrance to Our Lady of the Mountains Catholic Church. Our leader will be Karl Ricker.
