Are daddy longlegs the most venomous spider, with fangs too short to bite?

Arizona context

You can run into both kinds of daddy longlegs in Arizona. UC Riverside says harvestmen prefer moist places under logs and rocks but can also be found in the desert. The two cellar spiders most common in U.S. homes both came from Europe: Pholcus phalangioides, a gray spider found throughout the U.S., and Holocnemus pluchei, which is very common along the Pacific Coast and into the southwest deserts. University of Arizona Extension says Arizona's two most common venomous spiders are the western black widow and the Arizona recluse, not daddy longlegs.

What to do about daddy longlegs in your home

• Leave them alone if you can. University of California IPM says spiders are mostly beneficial because they feed on pest insects
• Vacuum spiders and webs from windows, room corners, storage areas and other seldom used spots
• Clean up clutter in garages, sheds, basements and other storage areas, and wear gloves while you do it
• Seal cracks in the foundation and gaps around windows and doors
• Weather strip doors, repair screens and cut down on the insects spiders feed on

Two different animals share one name

Harvestmen belong to their own group of arachnids, called Opiliones, separate from spiders. UC Riverside describes them as having one pill-shaped body with all eight legs attached to it and at most two eyes. They don't make silk, so you won't find one living in a web. They mostly eat decaying plant and animal matter, and they will catch prey when they get the chance.

Cellar spiders, in the family Pholcidae, are true spiders. They have two main body parts, eight eyes that are usually clustered at the front, and they spin webs out of silk. Because they are plentiful, especially in cellars, and easy for people to see, UC Riverside says they are most likely the animal people mean when they repeat the myth.

Why the myth doesn't hold up

Harvestmen have no venom glands, no fangs and no other way to inject anything, so for them the story is simply false. UC Riverside notes that some give off defensive secretions that might be toxic to small animals if eaten, but that isn't a bite.

For cellar spiders, there is nothing behind the claim that they are deadly. UC Riverside points out that their venom has never been tested on people and there are no studies testing how toxic it is to mammals, so there is no scientific basis for calling them especially dangerous.

The short fang part doesn't hold up either. Cellar spiders do have short fangs, but UC Riverside notes that brown recluse spiders have a similar fang structure, and they can obviously bite people.

When professional service is warranted

Call if you're seeing a lot of spiders or webs indoors, or if you find black widows or recluse spiders, which University of Arizona Extension names as Arizona's two most common venomous spiders. If a spider bite causes pain or any unusual reaction, contact your healthcare provider, or call Poison Control at 1-800-222-1222. This is general information, not medical advice.

How Hydra handles it

Our Service Pros identify which spiders you have before treating, remove webs, treat hiding spots and entry points, and help reduce the insects spiders feed on. To talk it through, call or text your local office to reach an Office Pro, or ask for a free custom quote.

Frequently asked

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Related questions

• Why are there so many spiders in my house in the fall?
• What should I do if I find black widows around my house?

References

• UC Riverside Spider Research: Daddy Long Legs
• University of California IPM: Spiders Pest Note
• University of Arizona Cooperative Extension: Spiders (Backyard Gardener #177)
• Arizona Poison and Drug Information Center: Bees, Spiders & Other Bugs