Cellar Spiders

Facts, Identification and Control

Scientific Name

Family Pholcidae

Appearance

The cellar spider is often found in damp locations like basements, crawl spaces and cellars, which is how it got its common name. Cellar spiders have small bodies with long, thin legs and are often confused with harvestmen, the true daddy longlegs that are not actually spiders. There are two groups of cellar spiders, the long-bodied cellar spiders that have legs up to two inches long and the short-bodied cellar spiders whose legs are about ½ inch long. Cellar spiders are tan or gray in color. Like all spiders, they have eight legs. The most common Phlocidae in the United States is the long-bodied cellar spider. Because of their long legs, cellar spiders are often mistaken for the “daddy longlegs.”

Cellar Spider

Behavior, Diet and Habits

Cellar spiders hatch from eggs, and when hatched, look like small adults who shed their skin as they grow. The female spiders encase their eggs in silk webs where they are protected against spider predators. Cellar spiders frequently infest homes and warehouses and make their webs in protective corners of basements, closets, attics, outbuildings and rock piles. They prefer to eat small moths, flies, mosquitoes and other insects or spiders that are found near their webs. Male and female cellar spiders may be found in climate-controlled structures year round. The spider reaches maturity in about a year. Once mature, the spider can live another two years.

The web of the cellar spider is irregular, with no discernable pattern. Although their bites are harmless to humans, their webs are unsightly and profuse: unlike other spider species, cellar spiders prefer to live within close proximity to one another, creating troublesome communities within human dwellings.

Like most other spiders, cellar spiders are highly adaptive and successful predators. Their diet consists primarily of insects, which they lure and trap within their webs before encasing them in cocoons. When food supplies in their environment are insufficient, these spiders travel to other webs and pretend to be trapped insects. As the other spider attempts to catch and consume it, the cellar spider attacks the unsuspecting arachnid. Also known as vibrating spiders, cellar spiders utilize wobbly, vibrating movements to confuse predators and attackers.

More Information

Not a medically important spider, cellar spiders aren’t known to bite people. However, this has not detoured the existence of an urban myth indicating that cellar spider venom is among the most deadly in the world, but the length of the spider’s fangs are too short to deliver the venom during a bite. There is no scientific based information to support the deadliness of their venom, so there is no reason to assume this is true. But, are the fangs too short to penetrate human skin? Cellar spiders do have short fangs, termed uncate by spider experts. But, so do brown recluse spiders that undeniably bite humans. Cellar spiders can be a nuisance around homes and businesses, despite their harmless nature. To help control cellar spiders, follow these tips:

  • Contact your pest management professional for advice on how to help control cellar spiders.
  • Use a broom or vacuum to remove webs, egg sacs and spiders.
  • Reduce the spider’s food sources by using insect prevention and control measures.
  • Use proper ventilation and dehumidifiers to reduce the humidity in your home or business.
  • Prevent pests from entering your home or business by sealing cracks and crevices around doors, windows and other entry points.
  • Always contact your pest management professional before using insecticides to ensure you are using the product safely and effectively.

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