Some 35,000 named species of spiders occupy Planet Earth, scientists say, and many thousands more have yet to be identified and named. Of those, some 3,500 species are native to North America. Yet remarkably few of those spider species are poisonous to humans. In California, including here in Sacramento, the spider that poses the greatest danger to humans is the black widow.

Here at Pinnacle Pest Control, we’re getting about four calls a day about black widow spiders, primarily from customers in the Elk Grove, Roseville, and Rocklin areas. Less than six months ago, we received a call about a customer of ours getting bit by a black widow spider. He’s fine now but was hospitalized for three days. The spider was living in one of his shoes. (He likes to wear loafers barefoot.)

The mature female black widow is larger than the male of the species, with a shiny, bulbous black abdomen and body length of about 5/16 to 5/8 inches, not counting its legs. The underside of the female’s abdomen is distinguished by red or orange markings in the shape of an hourglass. The male looks different, with a less pronounced abdomen, mottled grey-green markings overall, and a lighter, yellowish hourglass marking on his underside. If you are bitten, the female black widow is the likely culprit.spiders, primarily from customers in the Elk Grove, Roseville, and Rocklin areas. Less than six months ago, we received a call about a customer of ours getting bit by a black widow spider. He’s fine now but was hospitalized for three days. The spider was living in one of his shoes. (He likes to wear loafers barefoot.)

Black widows have a voracious appetite for insects, and as a result are often found out of doors or in garden sheds, garages, attics and cellars. They are nocturnal, and like to live in places where they can remain hidden by day, emerging to hunt at night. Thanks to their love of hidden places, you may have an unwelcome encounter with them while organizing your potting bench, rearranging your storage shed, or cleaning your garage. Curious kids and pushy pups also can be at risk. Be sure to wear gardening gloves when cleaning up yard waste, and shake out globes and boots before putting them on if they’ve been sitting around your garage for a while.

Initially a black widow bite may feel like a pinprick or bee sting, and you may see redness or a red streak at the bite site, with other symptoms coming on within the hour. Although the bite of a black widow is unlikely to be fatal, it can cause severe pain, muscle cramps, sweating, nausea and other uncomfortable symptoms, with increased danger for very young children, seniors and those with compromised immune systems. If you believe you or a family member have suffered a black widow bite, call your doctor immediately.

The black widow spider is sometimes mistaken for a couple of imposters who also appear in California: the brown widow, which has a mottled tan, brown, and gray, with an orange and yellow “hourglass”; and the false black widow, which is smaller than the mature black widow, chocolate brown in color and has no red marking on its underside. Neither of these is a true “California girl” but rather immigrated to the Golden State, the brown widow from Africa, the false black widow from Europe. Although these two also may bite, they are less venomous than the black widow. Primarily found in the southern part of the state, they have been gradually expanding their territory.

Although many spiders serve a beneficial purpose in the ecosystem and are harmless to humans, the black widow, when living in our homes and yards can pose a serious risk to children, pets and the hapless weekend gardener. Your pest control professional can correctly identify the types of spiders occupying your home or garden and advise you on ways to remove and prevent them from moving into your space. Meanwhile, be sure you shake out your loafers before sticking them on your bare feet!

Sources: http://www.explorit.org/science/spider.html; http://www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74149.html