Spider identification
Yes, there are black widows in Ontario, and yes, there are confirmed records in the Pinery and the Grand Bend dune country. They are also the most over reported spider on the lake. Almost every "black widow" photo taken in this area turns out to be a false widow, and the real one is shy, rare and easy to check for once you know the marking.
The female is glossy jet black, about 1 cm in the body with a round abdomen, and the marking is on the underside: a red hourglass that in the northern species is split into two triangles that do not quite touch, usually with a row of red spots down the top of the abdomen as well. Males and juveniles are small, striped in brown, white and red, and are rarely recognized. The web is a strong, irregular tangle low to the ground with a retreat in a crack or under cover. If you can see the underside and there is no red, it is not a widow.
Pockets of dry, sandy, undisturbed habitat across southern Ontario, mostly the Lake Erie sand country and oak savanna, with confirmed records in the Pinery, the Grand Bend dunes and scattered finds further north along the Lake Huron shore. On a property it would be in a woodpile, under a stone wall or stump, in a stump hole, or under patio furniture or a boat left out all winter. The black widows most Ontarians actually meet are western black widows arriving in grape bunches from California and Mexico, with an unbroken hourglass.
Adults are seen from June to September. They overwinter as immatures in deep cover and are not a species that moves toward houses in fall.
The only Ontario spider whose venom can make you ill, and still a rare event: the spider is shy and bites only when pressed against skin, usually a hand into a woodpile or under furniture. Symptoms are pain spreading from the bite, muscle cramping, sweating and nausea over a few hours; it is very rarely life threatening and treatment is supportive. If you think you were bitten, call the Ontario Poison Centre at 1-800-268-9017 or go to emergency, and bring a photo of the spider if you can. Most "spider bites" in Ontario are never confirmed; see the bite section of our guide to common spiders in Ontario for what a real one looks like.
If you think you have found one, do not handle it. Photograph it from a distance, including the underside if you can see it, and send it to us with your booking; we will tell you what it is. Where one is confirmed on a property we remove it with its web and egg sacs and treat the specific cover it was using, and we check the woodpile, stone and stored items nearby. Widows are not a species that spreads across a house, so this is site work, not a whole home treatment, and we will not sell you one. Every visit ends with a written summary of what we found and where product was applied, if any. Our spider control service and 60 day guarantee pages have the details and pricing.
False black widow, Common house spider. The false black widow is dark brown or purplish rather than jet black, has no red on the underside, and often has a pale line across the front of the abdomen. It lives under siding trim, in window wells and basements, which a widow almost never does. The common house spider is mottled brown in a dusty tangle on the porch ceiling. The full list with photos is in the common spiders in Ontario guide.
Good to know
There are confirmed records in the Pinery and the Grand Bend dune area, in dry sandy cover away from buildings. They are rare, shy and not a species that comes to houses. Most reports from the area turn out to be false widows.
Photograph the underside. A black widow is shiny jet black with red on the belly, two red triangles in the northern species. A spider with no red, or brown rather than black, is not a widow.
Leave it alone, photograph it from a distance and send us the photo. If someone has been bitten, call the Ontario Poison Centre at 1-800-268-9017. We can remove a confirmed spider and treat the cover it was using.
Related guides: False black widow in Ontario, Spider control in Grand Bend. Service areas where this spider is found: Grand Bend, Bayfield, Sarnia and Bright's Grove.
