Bugs like humidity, heat
Sep 09, 2007 - 12:00 AM
By Margaret Carney
“Here’s a bug question!” wrote Heather Sparacino in an e-mail. “Driving to work today I noticed what I thought were black clouds drifting along, because it was a rainy morning. But as I peered closer I could see they were actually clusters of dots, millions of them, all heading south. What are they?”
Due to the wonders of technology, Heather sent along a photo she’d taken from her car on the Markham Bypass, of insects swarming at the top of a tree like a plume of smoke. Flying ants, I thought immediately, though I wasn’t certain.
Eric Easson of Oshawa phoned later to talk about clouds of insects “like smoke” he’d seen along the 401 at Courtice Road that same day. My interest was piqued even more when Cyndi Ritskes called to chat about swarms of bugs she’d seen east of Newcastle, “as if the trees were smoking.”
“Was that last Thursday?” I asked her, and it was.
The clincher: I was talking to Otto Peter, president of the Durham Region Field Naturalists and he mentioned how a colleague at General Motors had come up to him in great excitement saying, “Did you see all the insects near the parking lot?” One had landed on his arm: a flying ant.
Wet, rainy August 23. The end of one of the longest droughts we’ve had for years. Every flying ant in the southeast corner of the GTA must have decided that was the day: mating time! They took off from their home colonies by the millions, queens and males swarming feverishly. They all go at once, a strategy to avoid being picked off by predators.
The virgin queens try to get away on their own, hoping to meet males of another colony and avoid inbreeding. They fly to a prominent point on the landscape -- treetop or chimney -- and emit pheromones to attract attention. And they get it.
By the end of the day it’s all over. The males die; a queen drops her wings, digs a burrow and starts laying eggs, the first of millions she may produce in her lifetime, all fertilized from the sperm now stored in a special organ in her abdomen.
Scientists believe “flying ant days” are triggered by humidity, temperature and wind conditions. In Africa they appear right before the big storms in summer.
Nature queries: mcarney@interlinks.net or 905-725-2116.
Durham Region resident Margaret Carney, in addition to writing nature-appreciation columns, has also published several children’s books.
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