Black widow spiders often spark concern, leading many to wonder about their presence. Knowing where they are found, how to identify them, and what to do if encountered provides valuable guidance.
Presence in Indiana
Black widow spiders are present in Indiana, with two species found in the state. The Northern black widow (Latrodectus variolus) is distributed throughout Indiana. The Southern black widow (Latrodectus mactans) is primarily located in the southern half of the state, becoming less common further north.
Identifying Black Widows
Identifying a black widow spider, particularly the female, involves recognizing several distinct traits. Female black widows are shiny black and measure about 0.4 to 0.5 inches in body length, extending up to 1.5 inches with their legs. Their abdomen is notably large and rounded.
A key mark is the red or orange hourglass shape on the underside of the female’s abdomen. For the Southern black widow, this hourglass marking is complete and connected in the middle. The Northern black widow has an hourglass marking that is broken or separated into two distinct red spots. Some Northern black widows may display red spots or white stripes on the top of their abdomen, especially when younger. Male black widows are much smaller than females and are not considered medically significant to humans.
Common Habitats and Behavior
Black widow spiders build their irregular, tangled webs in dark, undisturbed locations. These areas include woodpiles, under rocks, garden debris, and around construction openings outdoors. Indoors, they may be found in secluded spots like basements, crawl spaces, sheds, and garages.
These spiders are reclusive and construct their webs near ground level. Despite their potent venom, black widows are not aggressive and only bite when they feel threatened or provoked. Bites occur when a spider is accidentally pressed against skin, such as when reaching into a dark space or putting on clothing left undisturbed.
Safety and Response to Bites
To minimize encounters with black widow spiders, take precautions. Wearing gloves when handling firewood, gardening, or cleaning cluttered areas prevents accidental contact. Regularly decluttering spaces like basements, garages, and sheds removes their hiding spots. Shaking out shoes or clothing stored in undisturbed areas before wearing them is a practical measure.
If a black widow spider bite is suspected, seek prompt medical attention. While the initial bite may feel like a pinprick or go unnoticed, symptoms develop within an hour. Symptoms include sharp pain at the bite site, followed by muscle cramps and spasms that may spread to the abdomen, back, or chest. Other symptoms include nausea, vomiting, sweating, and headache. Washing the bite area with soap and water and applying a cold pack can help manage localized symptoms until medical care is received.