WEATHER UNIVERSITY: Move over crickets, dragonflies can forecast, too

Dragonflies, like many insects, are known to be strongly affected by changes in the weather. - 123RF Stock Photo

Since weather lore is a product of decades of careful observation, I love to get questions about things people notice.

Earlier this week, Paul Smith from Dominion, N.S., wanted to know if there might be a connection between the unusually high number of dragonflies and the heat wave. He has seen as many as six to 12 of them flying around at once.

GRANDMA SAYS: Chirping about the heat wave!

Great question Paul. Dragonflies, like many insects, are known to be strongly affected by changes in the weather. Dragonflies are exothermic, which means changes in temperature influence their behaviour. They are more active when it’s warm and a little lethargic when it gets too cool.

Wind also plays a role in a dragonfly’s activity level. On very windy days, they won’t fly at all, or it will be restricted to places that are protected from the wind. While dragonflies are powerful fliers, they still have limitations. They have massive, broad, flat wings and though they have bulky bodies, they just don’t weigh that much.

Light is known to impact flight activity, as well: more dragonflies tend to fly on sunny days than on cloudy days.

Finally, let’s consider rain. Several researchers have observed that dragonflies disappear from the water’s edge right before it starts to rain. This behaviour is fascinating and very smart.

So, there you have it, Paul. While this hot, windless weather has many of us scurrying indoors to our air-conditioned homes, the dragonflies are having a ball!