Northern black widow spider

Photo by Vicki Simkovic

Today's bug is Latrodectus variolus, known commonly as the Northern black widow spider. It is true that they are venomous and they normally use their venom to paralyze their insect prey and as self defense. However, they are not aggressive; they actually are very timid spiders. Once they find a place they consider comfortable, they build a small web and stay put. It's only when you disturb them that there is a small chance that they might bite although the spider prefers fleeing when disturbed. That’s a good thing because the venom of a widow spider is 15 times more toxic than that of rattlesnakes. However, due to the small amount of the venom injected into the bite, widow bites are far less serious. 

Northern black widow spiders are not commonly observed here in Ontario, but a few months ago a colleague of mine, a spider expert, together with participants of a so called Bioblitz found one (the image today is from their report). These spiders are primarily found in habitats with sparse vegetation, stumps, hollow logs and piles of debris. They are rarely found indoors. However, they may enter buildings on piles of firewood or other items brought inside.