Do Cellar Spiders Make Webs? Unraveling the Mystery

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Cellar spiders are often found in dark, secluded places like basements, crawl spaces, and cellars. These long-legged, delicate creatures may cause some people to wonder if they create webs like other spider species.

Indeed, cellar spiders do spin webs, which tend to be untidy and can sometimes become quite extensive. These webs serve as their habitat, and they also play a role in capturing prey. It’s interesting to note that when cellar spiders are disturbed, they are known to bounce within their webs as a peculiar defense mechanism.

Cellar Spider Basics

Species and Range

Cellar spiders belong to the family Pholcidae, which includes two common species – the long-bodied cellar spider (Pholcus phalangioides) and the short-bodied cellar spider. They are found across North America, thriving in dark, secluded places like cellars and basements.

Spider Identification

Long-bodied Cellar Spider:

  • Female body length: 1/4-5/16 inch
  • Leg length: Up to 2 inches
  • Color: Pale gray to light tan

Short-bodied Cellar Spider:

  • Female body length: 1/16 inch
  • Leg length: 5/16 inch
  • Color: Pale gray to light tan

Both species have long, delicate legs and are known for their “vibrating” behavior when alarmed, turning them into a blur in their webs.

Lifespan

Female long-bodied cellar spiders can produce about three egg sacs in their lifetime, each containing around 13-60 eggs. The exact lifespan of cellar spiders is not clear, but they can survive for several months to a year.

Conservation Status

Cellar spiders are common spiders and not considered endangered or threatened. Their presence is usually harmless, and they can even help control other pest populations by capturing and consuming small insects.

Long-bodied Cellar Spider Short-bodied Cellar Spider
Body length 1/4-5/16 inch 1/16 inch
Leg length Up to 2 inches 5/16 inch
Color Pale gray to light tan Pale gray to light tan
  • Long-legged and delicate
  • Common in North America
  • Vibrates when alarmed
  • Harmless and not endangered

Webs and Habitats

Web Structure and Maintenance

Cellar spiders create webs in calm, undisturbed places and usually live in or near their webs. These webs have a chaotic structure, and when disturbed, cellar spiders bounce rapidly to turn themselves into a blur, making it difficult for predators to locate them.

Webs need maintenance, so they don’t collect too much dirt and dust over time, which can make them unsightly. Regular vacuuming of the webs and spiders is recommended.

Preferred Locations

Cellar spiders prefer locations with:

  • High humidity
  • Low ventilation
  • Corners of rooms
  • Indoor or outdoor shelters

Examples of such locations include basements, caves, sheds, and garages. You can often find them in the corners of rooms, close to the ceiling.

To minimize cellar spider populations, consider:

  • Minimizing nesting habitats
  • Sealing exterior cracks and crevices
  • Regularly vacuuming webs

Here’s a comparison table of their preferred locations:

Web Location Humidity Ventilation Indoors or Outdoors
Basement High Low Indoors
Cave High Low Outdoors
Shed High Low Outdoors
Garage High Low Indoors
Corners of rooms High Low Indoors

Biology and Behavior

Anatomy and Appearance

Cellar spiders belong to the Pholcidae family and are characterized by their long, thin legs and small bodies. They come in various shades of gray, tan, or whitish color, which helps them blend into their surroundings. Their body length ranges from 1/16 inch for short-bodied cellar spiders to 1/4-5/16 inch for long-bodied cellar spiders, with legs extending up to 2 inches in the latter. A distinctive feature of cellar spiders is their flexible tarsi (“feet”), which adds to their wispy appearance1.

Diet and Prey

Cellar spiders primarily feed on insects, including mosquitoes, flies, and moths2. They rely on their webs to catch prey, waiting patiently in or near the web for insects to get trapped. Some cellar spider species even demonstrate a unique hunting technique, where they enter the webs of other spiders, mimic the vibrations of trapped insects, and devour the unsuspecting host spider when it approaches3.

Reproduction and Life Cycle

  • Egg sacs: Female long-bodied cellar spiders produce about three egg sacs over their lifetime4.
  • Number of eggs: Each egg sac contains 13-60 eggs4.
  • Spiderlings: After hatching, the spiderlings remain in the mother’s web for a short time before venturing out on their own5.

When alarmed, cellar spiders exhibit a remarkable behavioral trait known as vibrating or bouncing rapidly in their webs, which makes them appear blurred and camouflaged1. This movement helps them avoid predators and other dangers6.

Despite the myth that cellar spiders, also known as daddy long-legs spiders, are venomous, they pose no harm to humans, and their venom is not dangerous7. In fact, they are beneficial as they help control insect populations in homes and buildings8.

Cellar Spider Misconceptions

Daddy Longlegs Confusion

Cellar spiders are often confused with daddy longlegs, which actually refers to two different groups of arachnids:

  • Harvestmen: These are not even technically spiders, as they belong to a separate order called Opiliones.
  • Craneflies: Adult craneflies are insects, not spiders, and have wings.

The key differences between cellar spiders and these other arachnids include:

Feature Cellar Spiders Harvestmen Craneflies
Body segments 2 1 3 (insect)
Legs 8 (spindly) 8 6 (insect)
Wings None None 2 pairs

Vibrating Spiders

Another interesting and unique characteristic of cellar spiders is their habit of vibrating or bouncing rapidly in their webs when alarmed. This movement:

  • Turns them into a blur
  • May help deter predators by confusing them

Venom

Many people falsely assume that cellar spiders are venomous. In reality:

  • They do possess fangs and venom, but it is not dangerous to humans
  • They primarily use their venom to subdue small insects for consumption

In summary, cellar spiders are not daddy longlegs or harvestmen. They’re unique creatures that display interesting behaviors, such as vibrating, and possess venom that is harmless to humans.

Managing Cellar Spiders

Prevention and Control Measures

Cellar spiders are not known to be harmful, but they can cause unsightly webs that gather dust and dirt over time. To prevent and manage their presence in your home, follow these steps:

  • Sanitation: Keep your home and basement clean and clutter-free.
  • Crevices: Seal any gaps and crevices around your home using caulk or weatherstripping.
  • Lighting: Use yellow lights as they are less attractive to spiders and other insects.
  • Dehumidifiers: Maintain low humidity levels in your home using a dehumidifier.

Safe Removal Methods

If you discover cellar spiders in your home, here are some ways to safely remove them:

  • Vacuum: Use a vacuum cleaner with a hose attachment to remove the spiders and their webs.
  • Broom: Gently remove the spiders and webs using a broom, taking care not to harm the spider.

For stubborn infestations, consider using insecticides or contacting a professional pest control service. Always follow the directions on insecticide labels and consult conservation status guidelines to ensure safe and responsible usage.

Method Pros Cons
Vacuum Easy, quick, non-toxic May harm the spider
Broom Non-toxic, gentle on spiders Time-consuming
Insecticides Effective Toxic, may harm other species
Pest Control Professional help Costly

Remember that cellar spiders are generally beneficial creatures that help control other pests in your home, such as flies. So if their presence is not causing any issues, consider letting them coexist with you in a harmonious environment.

Cellar Spiders and Ecosystem

Predators and Threats

Cellar spiders are small arachnids with a range across the United States. They usually inhabit dark, damp spaces like rock piles and ceilings. These spiders face various predators, such as the orb weaver spider. One defense mechanism they have is to vibrate rapidly in their webs, turning them into a blur and making it difficult for predators to capture them.

  • Range: United States
  • Habitat: Rock piles, ceilings
  • Predators: Orb weaver spider
  • Defense mechanism: Web vibrations

Benefits to Humans and the Environment

Cellar spiders are crucial components of the ecosystem. For example, they help control insect populations by feeding on them. Their webs are not the typical concentric circles but still effectively trap prey. Humans benefit from cellar spiders because they help to reduce pests in homes and gardens.

  • Environmental role: Controls insect populations
  • Web type: Non-concentric circles
  • Human benefits: Pest reduction

Species

Various species of cellar spiders exist. The long-bodied cellar spider, for instance, is about 1/4-5/16 inch long with legs extending another 2 inches. In comparison, the short-bodied cellar spider has a 1/16 inch long body with legs extending about 5/16 inch1. Both species reproduce by the female storing sperm and producing egg sacs, with the long-bodied species producing 13-60 eggs each1.

Comparison of Cellar Spider Species:

Species Body Length Leg Length Eggs per Sac
Long-bodied 1/4-5/16 inch 2 inches 13-601
Short-bodied 1/16 inch 5/16 inch N/A

Footnotes

  1. https://mdc.mo.gov/discover-nature/field-guide/cellar-spiders 2 3 4 5

  2. https://extension.umn.edu/insect-relatives/spiders

  3. https://education.mdc.mo.gov/discover-nature/field-guide/cellar-spiders

  4. https://hgic.clemson.edu/factsheet/cellar-spiders/ 2

  5. https://extension.psu.edu/longbodied-cellar-spider

  6. https://mdc.mo.gov/discover-nature/field-guide/cellar-spiders

  7. https://extension.psu.edu/longbodied-cellar-spider

  8. https://hgic.clemson.edu/factsheet/cellar-spiders/

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Long Bodied Cellar Spider

 

Weird Bug
Location:  Thetford, Norfolk, England
September 26, 2010 3:57 am
I found this on my toilet wall very near 2 dead spiders. it’s about 5cm long.
Signature:  name of the bug

Long Bodied Cellar Spider

This sure looks to us like a Long Bodied Cellar Spider, Pholcus phalangioides, which has a worldwide distribution according to BugGuide.

Letter 2 – Long Bodied Cellar Spider

 

Subject:  Is that you Big Daddy?
Geographic location of the bug:  Ventura, Ca
Date: 02/23/2018
Time: 08:39 PM EDT
Your letter to the bugman:  Dear Bugman,
This long legged creature has been spotted in several locations in my home over the past few weeks. It is fairly sefentary, and often spotted while striking a pose, but rarely in action.
How you want your letter signed:  Melanie on the Irish Chain

Long Bodied Cellar Spider

Dear Melanie on the Irish Chain,
The Long Bodied Cellar Spider,
Pholcus phalangioides, is also commonly called a Daddy Long Legs or Cobweb Spider.  According to BugGuide:  “Generally found in and around man-made structures, or in other types of disturbed habitats” and that includes houses and apartments.  Long Bodied Cellar Spiders are considered harmless to humans.

Reader Emails

Over the years, our website, whatsthatbug.com has received hundreds of letters and some interesting images asking us about these insects. Scroll down to have a look at some of them.

Letter 1 – Cellar Spiders Dine

 

Subject: Pholcus phalangioides Behavior
Location: Jamul, California
November 11, 2012 7:58 pm
Today we watched as a group of cellar spiders first fought over and then communally dined on a trapped housefly.

Cellar Spiders trap a Fly

One of the larger spiders chased the others away, at one point almost appearing to ”box” with another. Then the bigger spider spent some time shoring up the web around the fly. Finally, all the spiders moved in, jockeyed for position, and peacefully settled down to dine. I’ve never witnessed this behavior before; needless to say, it was fascinating!
Signature: lkyoder

Cellar Spiders Dine

Dear lkyoder,
We are speechless at this awesome documentation and the spectacular close up photograph of this communal feeding behavior of the very domestic and harmless Cellar Spiders. We will speculate more later.

How many Legs do you count?

LOL. Then my work here is done!  Looking forward to alternative interpretations of what we observed.
Thanks, Dan, for looking and for all the hard work that you do!
Leslie

Hi again Leslie,
We suspect the largest spider is most likely a female and perhaps she was “boxing” with another female as a means of exerting her dominance.  We wonder what advantage there is to communal feeding.  This is such a fascinating posting.  Thanks again for sending it in.

Hi, Dan.
I joked on facebook that perhaps this is what Thanksgiving dinner looks like when you’re a cellar spider.
They were there for hours, incidentally. This morning, all are dispersed. . . .
Leslie

Update from Leslie
Hi, Dan. As you have no doubt figured out, I keep a very spider-friendly home. As a result, I’ve got a lot of webs, but the pic below I felt worth sharing. More cellar spider work, this was woven in the circular piece that tops a lampshade harp. I’d like to think that those of us who accommodate spiders get our own personal dream-catcher from time to time.
Best,
Leslie

Dreamcatcher Web of a Cellar Spider

Hi Leslie,
Though we have Cellar Spiders in our cottage office without a basement, we have never witnessed this communal dining nor the dreamcatcher web.  We do love the way Cellar Spiders shake their webs when they are disturbed.

Authors

  • Bugman

    Bugman aka Daniel Marlos has been identifying bugs since 1999. whatsthatbug.com is his passion project and it has helped millions of readers identify the bug that has been bugging them for over two decades. You can reach out to him through our Contact Page.

    View all posts
  • Piyushi Dhir

    Piyushi is a nature lover, blogger and traveler at heart. She lives in beautiful Canada with her family. Piyushi is an animal lover and loves to write about all creatures.

    View all posts
Tags: Cellar Spider

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