Canadian Canoe Routes - Technique - Problems - Biting Insects

Technique | Problems | Biting Insects | Mosquito

Mosquitoes
Blackflies
Horseflies
Ticks
What works ... what doesn't

Mosquito : Photo Credit Center for Disease Control - J. D. Gathany

We lucky Canadians have been graced with some 74 different species of mosquito, and I'm sure that at one time or another, I've been bitten by each one of them. These pests drone around with wings humming at a rate of 300-500 beats per second (ten times the speed of hummingbird wings).

How many mosquitoes do we have in Canada? Nobody knows, but a ballpark estimate of the US population is 10 trillion, and that's a small number compared to our prolific Canadian population. It has been estimated that the combined weight of mosquitoes in the Northwest Territories would exceed the combined weight of all of the caribou herds - a sobering thought.

Mosquitoes use a sensitivity to carbon dioxide to 'home in' on targets from great distances away. Once they get a bit closer, it is believed they use a sensitivity to heat to guide themselves. They fly around at a relatively slow speed - about 5 km per hour. A breeze of 15 km per hour is enough to send them fleeing. They are active day and night, but seem to be particularly bad in the evening hours.

Mosquitoes do their dirty work by sneaking a thin 'probe' through our skin. They inject a small amount of saliva which contains an anti-coagulant. It is this chemical that makes their bites so itchy. A mosquito can triple its' body weight during a single feeding.

When a female mosquito "bites" she is actually puncturing. She uses a very fine needle to pierce through the layer of dead skin to reach the blood. This needle is protected by a sheath that retracts during the operation.

All that a mosquito requires is the smallest of blood vessels called a capillary. There is sufficient blood pressure there that the mosquito simply has to make the puncture and the flow of blood does the rest.

Once the mosquito has filled up, sensors in the stomach called stretch receptors send a signal to the brain telling the mosquito that it's time to cap the well and move on. If those receptors don't work, or the brain does not respond, the mosquito can actually frill up until it explodes. For those who have the patience and the mean streak (let's call it scientific curiosity instead), there is a way to pinch the surrounding skin so that the mosquito is unable to withdraw its needle. This will also turn the mosquito into a balloon ready to burst.

The welt that forms around a mosquito bite is the result of an allergic reaction to mosquito saliva.

From "That's a Good Question 7 - More of the Best Good Questions Heard on CBC Radio One." Script Publishing Inc, 1997