Black widow spiders are recognized for their venom and distinctive appearance. They create egg sacs to protect their offspring. Knowing how to identify these sacs is important for homeowners and others who may encounter these arachnids, allowing for informed management decisions.
Identifying Black Widow Egg Sacs
Black widow egg sacs have specific visual characteristics. They are usually round or pear-shaped, measuring 12 to 15 millimeters in diameter, comparable to a large pea or small marble. Their color is often off-white, tan, creamy, or yellowish.
The sac’s texture is often papery or silken. Black widow sacs have smooth, well-defined edges. Each sac serves as a protective casing for hundreds of eggs. A single sac can contain 25 to 900 eggs, though 200 to 300 eggs per sac is common.
Common Locations for Egg Sacs
Black widow spiders prefer to construct their egg sacs in dark, undisturbed, and sheltered areas. These locations offer protection from predators and provide a stable environment for developing eggs. Common hiding spots include beneath rocks, logs, or outdoor furniture. They are also found in cluttered garages, sheds, basements, and crawl spaces.
Indoors, egg sacs may be located in low-traffic areas like storage closets, cellars, and attics. Outside, they can be found beneath eaves, window sills, and in woodpiles. The female spider often places these sacs within her irregular, tangled web, typically built close to the ground. This placement ensures the sacs are protected until the spiderlings hatch.
Safe Handling and Removal
Approaching black widow egg sacs requires caution, as the female spider is protective of her offspring and may bite if threatened. Avoid direct contact with the sacs due to the potential presence of the female spider or hatching spiderlings. Wearing protective gloves and long-sleeved clothing is recommended when attempting removal.
An effective removal method involves using a vacuum cleaner with a hose attachment to carefully suck up the egg sac. Immediately after collection, dispose of the vacuum bag or contents in a sealed plastic bag in an outdoor trash receptacle to prevent spiderlings from escaping. For sacs in accessible outdoor areas, carefully crushing the sac with a hard object like a shoe is an option. For multiple sacs, difficult-to-reach locations, or a suspected large infestation, contact a professional pest control service for safe and thorough management.