The Purdue Plant and Pest Diagnostic Laboratory

P&PDL Picture of the Week for
February 3, 2014

Cellar Spiders - Nuisance, not venomous

Timothy J. Gibb, Department of Entomology, Purdue University

Some of the most common spiders found inside homes are Cellar Spiders. These are sometimes confused with ‘Daddylonglegs’ and the mix-up is understandable. Both have long legs. However, that is where the similarity ends. The common name Daddylonglegs refers to ‘harvestmen’ – a separate order of arachnids usually much larger and almost always found out of doors. In fact these are not considered spiders at all.

Cellar spiders belong to the spider family Pholcidae. They can be recognized by their long and skinny legs and relatively small, rectangular, tan or brown body - usually less than ¼ inch in length. They appear very delicate and they have an interesting behavior of actually bobbing and weaving in a fascinating, dance-like motion when at rest.
I developed an interest in spiders as child. As far back as I can remember it was always my job to catch and remove spiders from the home.

Why I was the one assigned spider removal remains a matter of debate. My mother says I was given the responsibility because I showed an early interest in bugs and spiders. My brother says that because no one was sure if the spiders could bite or not, Mother put her least favorite child on that task. 

Either way, I learned that all spiders exhibit very interesting and often diverse methods of capturing prey. Cellar spiders are no different. They make a very loose, messy web that is somewhat sticky for small prey such as moths, flies, gnats, and springtails. As the potential prey wanders by, it becomes entangled or at least distracted by the webbing whereupon the cellar spider rushes to the site, lassos the prey using its long legs and then loops the victim with a silk strand time and time again until it is completely wrapped and immobile. Only at that point does the cellar spider venture closer and use its sharp, jaw-like chelicerae to dispatch and eat its catch.

The name, cellar spider, originates from the location where they are often found: damp cellars, basements, and crawl spaces. Cellar spiders also prefer shady corners in pantries, closets, attics, barns, and sheds.

They are not particularly harmful - not known to bite people or pets. Cellar spiders are simply a nuisance and can be easily removed without using pesticides. Simply vacuum or sweep them up, or send a small boy to do the job.

Click image to enlarge

Cellar spider

Purdue Plant & Pest Diagnostic Lab Purdue Cooperative Extension Service