Friday, June 23, 2017

Whispering Killer Wings

I love the sound of dragonfly wings in the evening.

From my deck easy chair I savour the whispering clicks of their translucent wings as they float through the air like prima ballerinas. Such grace. Such precision. Such great killers.

They move like ballet dancers but are powerful war machines, intercepting and destroying millions of blackflies, mosquitoes and other flying terrors that arrive each summer to torment us. They actually catch their prey with their feet and tear their wings off so they can’t escape. Then they chew them up with their razor mandibles.

I love them and the work they do. Sometimes when the Irish whiskey jug accompanies me to the deck I stand shouting: “Attaway. Way to go. Kill baby, kill!”

Dragonflies are said to have a 97-per-cent success rate in hunting. A single dragonfly eats hundreds of mosquitoes, blackflies and midges every day. It can eat its weight in mosquitoes in 30 minutes.

They have a computer-like connection between their tiny brains and their flight controls. Each of their four wings can operate independently, allowing them to fly backwards, sideways; basically any direction that they wish at average cruising speed of 16 kilometers per hour and top speeds of 30 to 40 kph.

Their heads are pretty much all eyes that give them exceptional vision, combined with an uncanny ability to focus and zero in on prey. They are able to select and target a single blackfly among an entire swarm.     

They are said to have the best vision of anything in the animal kingdom. Humans have three light sensitive proteins that allow us to see colour and details. Dragonflies have up to 33, which allows them to see colours that humans cannot even imagine.

Although they are deadly hunters, dragonflies do not bother with humans. They don’t bite us because their razor mandibles are not strong enough to break human skin.

It is a strange twist of nature that the much tinier blackfly is able to cut human skin, allowing it to soak up the resulting blood. Only the female blackfly bites because she needs blood for laying her eggs.

The blackflies thankfully are almost done for this year. They usually come out in mid-May and are mostly gone by the end of June. The life span of a black fly is only three weeks, far too long for many people.

Mosquitoes, however, are with us for the entire summer and the early autumn. They are continually laying eggs that produce adult mosquitoes in less than 10 days if conditions are perfect. And they are perfect right now – 22 to 27 degrees Celsius with plenty of humidity.

Like the blackfly only female mosquitoes bite, or to be accurate, drill down to get blood for egg development. Females live only one or two weeks, which of course gives them plenty of time to lay hundreds of eggs that become new populations.

While blackflies like moving water for hatching, mosquitoes prefer slow moving or still water. That is why it is so important to get rid of small puddles of standing water around homes and cottages. Even a Frisbee left overturned in the rain will collect enough water to become a breeding site.

Dragonflies were among our planet’s first insects and are believed to have been around for 300 million years. There are more than 3,000 known species of dragonflies, some of which now are endangered because of habitant loss and pollution, notably pesticides and insecticides.

There is enough concern about and interest in dragonflies that dragonfly sanctuaries are being developed. In recent years important sanctuaries have been established in the United Kingdom, Japan and the U.S. southwest.  

Dragonflies are found throughout the world and are important not just because they eat other flies that irritate us. Their exceptional vision and flying mechanics have been studied to help advance engineering innovations.

They also have symbolic importance. For some people they represent adaptation and transformation. For others, joy and lightness of being, and yet others, power and poise.

Samurai in Japan see the dragonfly as symbolising power, agility and victory. The Chinese see the insect as prosperity and good luck.


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