The terms "cellar spider" and "daddy long legs" are often used interchangeably, leading to considerable confusion. However, these names actually refer to two distinct groups of arachnids with key differences in their appearance, behavior, and even taxonomy. Let's delve into the specifics to clear up this common misconception.
What is a Cellar Spider?
Cellar spiders, scientifically known as Pholcidae, are a family of small, delicate spiders often found in dark, damp places like cellars, basements, and sheds—hence their name. They are characterized by their:
- Long, thin legs: While they do have long legs, they are proportionally longer than those of harvestmen (see below).
- Small bodies: Their bodies are relatively small compared to their leg span.
- Tangled webs: They spin irregular, three-dimensional webs that are often messy and sticky.
- Fast movements: They are surprisingly quick and agile, often darting around their webs.
Cellar spiders are generally harmless to humans. Their venom, while present, is considered too weak to cause significant harm. They are primarily insectivores, feeding on smaller insects that get trapped in their webs.
What is a Daddy Long Legs?
The term "daddy long legs" commonly refers to two completely different creatures:
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Harvestmen (Opiliones): These are arachnids, but they are not spiders. They belong to a distinct order, Opiliones, and lack the defining characteristics of spiders, such as the two-part body (cephalothorax and abdomen) and spinnerets for silk production.
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Cellar Spiders (Pholcidae): As discussed above, this is a common colloquialism for cellar spiders.
Let's focus on harvestmen, as they are the true "daddy long legs" in many people's minds. They are distinguishable by:
- Single body segment: Unlike spiders, they have a single body segment.
- Short, thick legs: Their legs are relatively shorter and thicker than those of cellar spiders.
- No silk production: They do not produce silk or build webs.
- Scavengers: They are primarily scavengers, feeding on dead insects and decaying organic matter.
Harvestmen are also generally harmless to humans. They possess no venom glands and pose no threat.
Are Daddy Long Legs Poisonous?
Are Cellar Spiders Poisonous?
This is a frequently asked question, often fueled by myths and misinformation. While cellar spiders do have venom, it's so weak that it's considered harmless to humans. There is no documented case of a cellar spider causing any significant harm to a human through a bite.
Are Harvestmen Poisonous?
Harvestmen are completely non-venomous. They lack venom glands altogether. This is a crucial distinction from spiders.
What is the Difference Between a Cellar Spider and a Daddy Long Legs? A Summary Table
| Feature | Cellar Spider (Pholcidae) | Harvestman (Opiliones) |
|---|---|---|
| Classification | Spider (Araneae) | Arachnid (Opiliones) |
| Body Segments | Two (cephalothorax and abdomen) | One |
| Legs | Long, thin | Shorter, thicker |
| Webs | Builds irregular, three-dimensional webs | Does not build webs |
| Feeding | Predatory (insectivorous) | Scavenger |
| Venom | Present, but weak and harmless to humans | Absent |
Conclusion
The confusion surrounding "cellar spiders" and "daddy long legs" stems from the colloquial use of the latter term. By understanding the distinct characteristics of cellar spiders (Pholcidae) and harvestmen (Opiliones), we can appreciate the differences between these fascinating arachnids and dispel common myths regarding their venom and danger to humans. Both are generally harmless and play important roles in their respective ecosystems.
