Black widow spiders in Ont. not cause for alarm
CTV.ca News Staff
Published Thursday, July 23, 2009 2:35PM EDT
An entomologist is taking a bite out of tales being woven about a scourge of black widow spiders entering Canada.
Reports have emerged that the dangerous spiders are being found in Ontario. Two have been found in the Toronto area in the past year -- one in a garage in Mississauga and another in a cottage in Bolton, north of Mississauga.
And where there are two, there are likely more, the thinking goes.
Since the "spiderlings" of black widow spiders leave home by spinning a sail-like web and throwing themselves to the winds, they could land anywhere.
This is not the first time the spiders have been spotted in Ontario. In decades past, they've been sighted in London, Barrie, along the Bruce Peninsula and on some Georgian Bay islands.
They're usually found around wood piles, trash piles, storage sheds, vegetable gardens and under rocks. They like it where it's dark, a little damp, and where they can find their favourite food: flies, mosquitoes, beetles, and grasshoppers.
Antonia Guidotti, an entomology technician at the Royal Ontario Museum, says while black widow sightings make headlines, Ontario is not exactly undergoing a scourge of the famed eight-legged arachnids.
"The black widow is very rarely encountered. Most of us, even entomologists, haven't seen a black widow in the wild in Ontario. Most of you are never going to see one. And the risk if you come across one is very small," she assures, speaking to Canada AM Thursday.
Guidotti says even if one should have the misfortune of encountering a black widow, the spiders present a much smaller danger that we've been led to believe.
"They're not aggressive; they're a very timid spider," she says. "Once they find a place that's comfortable for them, they make a little web and stay put. It's when you disturb them that there's a small chance that they might bite."
The species that has been spotted in Ontario is the latrodectus variolus, the Northern Black Widow. Even if you come across one, if it's not the female, it's harmless; the male black widow - which is actually brown, not black - doesn't bite and doesn't have venom.
It's the female, the one who often makes a meal out of males after she's mated with them, who can bite.
But she's fairly easy to identify. She's shiny black, with a large abdomen and a red or yellowish marking on the underside of her belly. While in some black widow species the red mark is in the form of an hourglass, in the Northern Black Widow, the abdomen markings are two red triangles whose tips don't quite touch.
In the remote chance that someone comes across one of these spiders -- and even in the more remote chance that one is bitten by one, it's not as though someone would die instantly. In fact, they likely wouldn't even need any medical care at all.
"A bite is not fatal. There's a less than one per cent chance of being fatal. And in those cases, it would be in a small person or someone who was elderly or in ill health."
The symptoms of a black widow spider bite are muscle cramps and stomach cramps that last a few hours to a few days.
In those who develop more serious effects, such as difficulty breathing, antivenom can be administered, though, admittedly, there isn't much of it Canada since black widow spider bites are so rare.
Nevertheless, with a network of zoos and poison centres across North America that stock it, supplies of antivenom can be shipped in to wherever needed.
Guidotti says the bottom line is that while Canadians might want to keep an eye out for the rare spider, there is no reason for fear.
"Don't go spraying and don't go killing every spider you see because it's not necessary," she says.