Black widows do not live in groups. They are solitary, cannibalistic spiders whose only social interaction is mating. However, you can absolutely find dozens of them clustered in the same area, which is why this question comes up so often. That clustering isn’t cooperation; it’s multiple loners drawn to the same favorable habitat.
Why Black Widows Are Strictly Solitary
The southern black widow (Latrodectus mactans) is described by biologists as timid, sedentary, solitary, cannibalistic, and nocturnal. Each spider builds and maintains its own irregular web, hunts its own prey, and will eat other black widows if given the opportunity. There is no shared web, no cooperative hunting, and no division of labor. No species in the entire Latrodectus genus has been documented building communal webs or living socially.
This puts black widows in sharp contrast with the handful of spider species that are genuinely social, like certain velvet spiders or some cobweb spiders in the tropics that share massive communal webs and cooperate in catching prey. Black widows simply don’t do this.
Spiderlings Stay Together Briefly
The one stage of life where you’ll see black widows grouped together is right after hatching. A single egg sac contains an average of 255 eggs, and a female often produces several sacs in her lifetime. When spiderlings emerge, they cluster together for days to weeks before dispersing.
That dispersal is driven partly by sibling cannibalism. The spiderlings will eat each other if they stay in close quarters too long. Many also fall to predators. To escape, spiderlings climb to a high point on nearby vegetation and release fine silk threads that catch the wind, carrying them anywhere from a few meters to several kilometers away. This “ballooning” behavior scatters them across the landscape, and from that point on, each spider lives alone.
Why You Find So Many in One Spot
If black widows are solitary, why do people sometimes find ten or twenty of them under the same deck or along the same wall? The answer is habitat, not social behavior. Black widows seek dark, sheltered retreats: holes between bricks, gaps around pipes, woodpiles, cluttered garages, spaces beneath outdoor furniture. When a structure offers many such hiding spots in a small area, multiple females independently settle nearby.
According to the University of California’s Integrated Pest Management program, in supportive habitats mature females can be found every few feet and sometimes within inches of each other. They aren’t interacting. They’re each occupying their own tiny territory because the conditions are right: plenty of crevices, insect prey attracted to outdoor lighting, and protection from weather. Remove those conditions and the density drops.
Managing a High-Density Situation
Finding multiple black widows around your home doesn’t mean you have a “colony” to deal with. It means your property offers good real estate for solitary spiders. The most effective approach targets the habitat itself rather than individual spiders.
Start by reducing clutter and shelter opportunities:
- Remove debris from garages, sheds, and along foundation walls. Unused cardboard boxes, stacked lumber, and piled equipment are prime hiding spots.
- Switch to sealed plastic containers for long-term storage instead of cardboard.
- Move outdoor items away from walls so spiders can’t nest in the gap between objects and the house.
- Seal entry points with caulk or weatherstripping. Replace damaged screens and install door sweeps where gaps exist.
For active removal, a vacuum with a hose attachment works well on visible spiders, webs, and egg sacs. After vacuuming, seal and discard the bag outdoors (or empty a bagless canister into a sealed trash bag). Be careful with egg sacs: crushing one can release hundreds of spiderlings into the area.
Always wear gloves, long sleeves, and closed-toe shoes when working in areas where black widows might be hiding. Never reach into dark spaces you can’t clearly see into, whether that’s a storage box, a woodpile, or a gap behind shelving. Black widows are nocturnal and hide during the day, so they’re often tucked deep into exactly these kinds of spots.
Pesticides labeled for spider control can help in targeted applications, but broad surface spraying is often ineffective because the product needs to reach the spider directly or penetrate its hiding place. If you’re repeatedly finding black widows indoors, spotting multiple egg sacs, or dealing with nesting in hard-to-reach areas, professional pest control is a reasonable next step.