Finding a small, silken object attached to a wall often causes immediate concern, as this is a spider egg sac. These protective structures are crafted by a female spider to house and safeguard her developing offspring. Since one sac can contain dozens to hundreds of spiderlings, recognizing this structure is important for managing the spider population. Identifying the appearance of the sac is the first step in determining the type of spider present.
General Characteristics of Spider Egg Sacs
Spider egg sacs are consistently made from silk, but their specific appearance varies widely depending on the species. These silken pouches protect the eggs from predators, environmental changes, and moisture until the spiderlings hatch. Sac size ranges from just a few millimeters (the size of a pinhead) up to two centimeters in diameter (the size of a small marble).
Most newly constructed sacs are white, cream, or pale yellow, though some may darken to tan or brown over time. The texture is a distinctive feature, varying from soft, fluffy, or woolly to smooth, compact, or papery. While many are spherical or round, other common shapes include teardrop or flask-shaped configurations.
Identifying Sacs by Common Spider Species
The specific visual attributes of an egg sac often indicate the species of spider responsible. For instance, the common house spider sac is typically teardrop-shaped with a papery, tan, or brown texture. These sacs are often found in the corners of rooms or garages, suspended within the messy, tangled webbing characteristic of this species.
In contrast, the black widow spider produces a sac that is smooth, round, and papery, often appearing light tan or cream-colored. These sacs are about half an inch across and are often suspended in dark, undisturbed areas. The brown widow, a related species, creates a highly distinct egg sac that is white or tan and covered in spiky, pointed projections, resembling a small medieval mace.
The brown recluse spider creates a small, off-white to cream-colored sac made of loose, thin silk that appears somewhat flattened or cushion-like. These sacs are typically found tucked away in secluded, low-traffic areas like closets, attics, or behind stored items. Jumping spiders construct flat, disc-shaped sacs that are tightly woven and smooth, often found attached to walls or tucked into crevices.
Safe Removal and Prevention Strategies
Once an egg sac is located, the recommended removal method is using a vacuum cleaner with a hose attachment. This allows the sac to be safely removed without direct contact, minimizing the risk of accidentally crushing it and releasing the spiderlings. Immediately after vacuuming, the vacuum bag must be sealed and disposed of in a lidded outdoor trash receptacle. If using a bagless vacuum, the canister should be emptied outdoors into a sealed bag.
To prevent future egg sacs, focus on exclusion and environmental management. Sealing cracks, gaps, or crevices around windows, doors, and the foundation of the home removes potential entry points for spiders. Reducing clutter in storage areas, basements, and attics eliminates hidden places where spiders prefer to lay eggs. Regular cleaning and dusting of corners disrupts web construction and prevents the establishment of new nesting sites.