News » Environment

Naturespeak

comment

Dragonflies forever

By Tina Symko & Dan White,

Whistler Naturalist Society

This 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, it seemed like it just couldn’t get any better than this, swimming in a fresh mountain lake at sunset.

ZOOOOOOM! What the heck? Ooooh, a dragonfly! I love dragonflies! They are so beautiful!

This one 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.

Dan said he’d never heard of such a myth but he seemed happy about it and mumbled something about buying a lottery ticket. I swam around chasing dragonflies for a while, trying to get one to land on me so I could be lucky forever too.

That night, Dan chipped his tooth big-time, resulting in an emergency trip to the dentist. He wasn’t feeling so lucky and questioned me about the whole dragonfly-landing-on-you-means-luck-forever thing. I don’t remember where I heard that myth, but the conversation piqued our interest about dragonflies in general. We were amazed at how little we knew…

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, these predators thrived – imagine pre-historic dragonflies with wingspans up to 70cm wide! 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 will spend 2-5 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. The dazzling winged predators that we see during summer represent only the final few weeks of a lifetime. As young dragonflies mature, their wings acquire the beautiful shimmery colouring for which dragonflies are well known. Actually, it is the shell of their wings that scatter the light, colouring the wings in the same way that rainbows are formed. Fully mature, the dragonfly returns to the water to breed and the cycle begins again.

Characteristically large wings and other physical characteristics make them a superbly designed aerial predator. Dragonflies can fly up to 50 km/h and stop in an instant. A slow wing beat-rate results in a relatively quieter buzzing noise, giving the dragonfly a great hunting advantage. Because its legs are directly under its mouth, 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. 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. Dragonflies’ aquatic habitats have been heavily impacted over the last 100 years. Wetland habitat decreases as areas become developed and stream habitat becomes degraded, threatening some of the world’s most beautiful and ancient species. When you see a dragonfly showing off its aerial wizardry 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

Au Natural! Nature Exposed Photo Showdown! Friday, Sept. 26 at Millennium Place. Local photographers show off their talents showcasing regional natural beauty. For more information contact Kathryn Shepherd at 604-935-8472 or Veronica Woodruff at veronicarobin@yahoo.ca .

BC River’s Day- Sunday, Sept. 21, 11 a.m.-3 p.m. at Rainbow Park. Come and join the annual celebration of our rivers and streams. Learn how to map a wetland, see the types of critters that live there on display, take a complimentary canoe for a paddle or look through historical exhibits from the Whistler Museum and Archives Society.

Add a comment