The Fascinating World of Spider Reproduction and Development

The Amazing World of Spider Eggs and Egg Sacs

Spider eggs are tiny wonders of nature that hold the next generation of arachnids. These egg sacs, carefully crafted by mom spiders to protect their baby spiders as they grow and develop, are an incredible example of spider survival strategies.

What Do Spider Eggs Look Like?

You’re more likely to spot egg sacs than the spider eggs themselves. Spider egg sacs (not “egg sacks”) are small, round or teardrop-shaped bundles made of silk. They’re often white, cream, or pale yellow and can range in size from a small marble or pea to larger sizes depending on the species.

For example, the sac of a common house spider is typically about the size of a small marble, while the sac of a garden spider is slightly larger and more robust. The sac of a brown widow spider is smaller and spikier.

Where Do Spider Eggs Commonly Appear?

Spider egg sacs can show up in a surprising variety of locations. Many species of house spiders create their sacs in hidden corners, under furniture, or tucked away in closets. Resident spiders in basements or attics might place their sacs along walls or ceilings, using their own webs to secure them in place.

Outdoors, other spiders often hide their eggs in leaf litter, under rocks, or attached to plant stems. Wolf spiders carry their egg sacs attached to their abdomen, ensuring their babies stay warm and protected wherever they go. Widow spiders, like black widows, hide their egg sacs in dark, quiet spots like woodpiles or sheds.

What to Do If You Find Spider Eggs in Your House

First, don’t panic. Spider egg sacs are completely harmless, even if their future occupants might make you uneasy. If you’re okay with spiders and appreciate their role as natural pest controllers, you can leave the sac alone. Let the babies hatch and move on, helping to control insect populations in and around your home.

If you’d rather not share your space with spiderlings, carefully remove the sac using a tissue, broom, or vacuum. Be sure to check for more sacs nearby, as many species of spiders lay multiple sacs in one location. For venomous spiders like black widows, consider contacting pest control to safely remove the sacs and adult spiders.