Cellar Spiders

How to identify Cellar Spiders

Longer than most other spider species, the cellar spider ranges from 7 to 8 mm in length, not counting the legs. Including the length of the legs increases the total length of the body by more than six times. The abdomen of the cellar spider is three times greater in length than width and cylindrical in shape. Colouration ranges from pale tan and yellow to grey.

Signs of an infestation

Webs left by cellar spiders contribute to their status as nuisance pests. Where many species consume old spider webs before spinning a new one, cellar spiders continue to add to existing webs. Spotting loose or haphazard webbing, especially in corners, indicates the presence of cellar spiders. Additionally, the sight of adult cellar spiders lingering in dark, quiet, and musty locations around the building and surrounding property points to an infestation problem.

Cellar Spiders Removal

Cellar spiders are particularly easy to remove from buildings with the assistance of a vacuum cleaner. Vacuum up any webbing and adults, and empty the vacuum bag or canister into a sealable trash bin. Keep an eye out for new webs that indicate further cellar spider activity. Especially large infestations may require treatment with appropriately labelled pesticides by a pest management professional.

How to prevent Cellar Spiders from invading

Manage humidity levels with dehumidifiers, ensure proper ventilation of cellars, seal cracks around doors and windows, change your outdoor lighting to yellow.

Habitat, Diet, and Life Cycle

Habitat

Cellar spiders derive their name from their preferred habitat. Found year-round in heated structures, the pests like to dwell in cellars, warehouses, basements, crawl spaces, garages, caves, and other dark and quiet environments. The long-legged spiders also prefer higher levels of humidity.

Diet

Like most spiders, cellar spiders are beneficial creatures that prey on other pest species. They target insects, other spiders, and small invertebrates, particularly ants.

Life Cycle

From egg to adult, immature cellar spiders take about one year to fully develop. Females produce as many as three egg sacs over the course of their lifetime. Each generation may yield 13 to 60 offspring at a time. Instead of attaching eggs to webs, walls, or other surfaces, cellar spiders hold the sacs with their mouthparts until the eggs hatch. Mature adults enjoy a lifespan of approximately two years.

Commonly Asked Questions

How worried should I be about cellar spiders?

Cellar spiders can live for about two years and produce up to 60 offspring. They do not actually cause structural damage to homes or other buildings, or pose health risks to humans. However, they are generally considered a pest and can be an alarming sight for anyone with arachnophobia.

If you spot any cellar spiders or their webs around your home, you can use a vacuum to remove them, making sure to empty the debris into a sealable bin. However, for large infestations, it is best to contact a professional pest control service to remove these pests effectively.