When discovering a black widow spider, a common initial reaction is concern about the potential for more to be present. Black widows are venomous spiders found across North America, recognized by their shiny black bodies and the distinctive red hourglass marking on the underside of the female’s abdomen. This article provides clarity and practical guidance regarding black widow spiders.
Understanding Black Widow Habits
Black widow spiders are generally solitary, living alone except during mating periods. Therefore, finding a single adult does not automatically indicate a large infestation of other adults. However, its presence suggests favorable local conditions, such as ample food or undisturbed hiding spots.
A significant indicator of potential increase is an egg sac. Females can produce multiple sacs, up to ten, during their lifespan. Each silk-woven egg sac can contain 255 to 900 eggs.
Once hatched, spiderlings emerge from the sac and quickly disperse. They often use “ballooning,” releasing silk threads to be carried by wind to new locations. Many spiderlings do not survive due to predation, including cannibalism, limiting the number that reach adulthood. While an egg sac means many spiderlings could emerge, they tend to spread out rather than forming a cluster of adult spiders.
Common Hiding Spots for Black Widows
Black widows build irregular webs in dark, secluded, undisturbed areas, often close to the ground. These locations provide protection and opportunities to catch prey. Understanding their preferred habitats helps identify where they might be present.
Indoors, black widows are frequently found in garages, basements, crawl spaces, and attics. They also use cluttered areas like storage closets, boxes, or rarely used shoes. These spiders seek out quiet corners and protected ledges within a structure.
Outside, common hiding spots include woodpiles, sheds, and under rocks or outdoor furniture. They may also live in hollow logs, stumps, or building foundations. Their webs are typically found in sheltered spots like under eaves or in irrigation control boxes.
What to Do if You Find a Black Widow
When you find a black widow spider, remove it cautiously. For individual spiders indoors, a vacuum cleaner with a hose attachment can be used to capture the spider, and the vacuum bag sealed and disposed of outside. Outdoors, if safe, a long tool or jar can crush or trap the spider. Always wear thick gloves to prevent direct contact.
To reduce future encounters, implement several preventative measures. Decluttering storage areas like basements, garages, and sheds removes potential hiding spots. Sealing cracks and crevices in foundations, around windows, and doors blocks entry points into your home. Regular cleaning, including vacuuming and removing cobwebs, also helps deter them.
When working in areas where black widows might reside, such as moving firewood or gardening, wear protective gloves. Keeping outdoor vegetation trimmed, especially near the house, reduces harborage areas. Storing firewood away from the house and off the ground further minimizes their presence. If you observe many black widows or egg sacs, or if they are in high-traffic areas, contact a professional pest control service.