Black Widow Spiders in Ohio


Joe Boggs reported that he received one his first offers of the season from a helpful homeowner who was interested in sharing a "rare" black widow spider that they had captured.  They believed black widows do not occur or are rarely found in Ohio; a common misconception.  In fact, both the southern black widow (Latrodectus mactans), and the northern black widow (L. variolus) are found throughout the state.  However, they are not commonly encountered because of their secretive habits.  The widow spiders are grouped with "cobweb weavers" (family Theridiidae) and produce a small, tangled web.  They are medium-sized spiders with bulbous abdomens and a covering of short, fine surface hairs that give them a shiny or satiny sheen.  Of course, black widows

The old saying, "hour-glass red, you are dead," is based on two other misconceptions about black widows.  The deep red marking on the underside of the abdomen is not always shaped like an hour-glass, and it may be orangish-red or yellow.  The middle part of the hour-glass may be missing, or there may only be some variation of a "V"-shaped marking.  Some individuals have no markings, while others sport a red line on the top of the abdomen.  Male spiders are about half the size of female black widows and their abdomen has red spots flanked by white lines or bars.  Of course, the males are notoriously short-lived once they meet a female...the females are called "widows" for a good reason.

While there are historical records of deaths being caused by black widow spiders, the spiders are not aggressive and seldom venture into occupied homes or buildings.  Both the northern and southern black widows prefer to live outside in old abandoned buildings, barns, and wooden outhouses.  Indeed, painful encounters declined with the widespread adoption of indoor plumbing.  The northern widow also resides under rocks or logs, and may occasionally be found within dense shrubs.  Their coloration provides perfect camouflage for remaining undetected by allowing them to blend into shadows.  If you find a black widow outdoors, simply leave it alone.  The spiders do not represent a serious threat.  Indeed, they are considered beneficial since they do represent a serious threat to insects.