Pholcidae
Web builder; uses irregular, non-adhesive webs to trap prey and envelops them with silk.
Pholcidae, commonly known as cellar spiders or daddy long-legs spiders, are a widespread family of araneomorph spiders found on every continent except Antarctica. They are distinctive for their extremely long, thin legs and a unique eye arrangement of two groups of three eyes, often with a small pair in between. These spiders construct irregular, non-adhesive webs in dark, undisturbed locations, both in natural environments and human habitations.
Key Facts
- ›Pholcidae are found worldwide, excluding Antarctica.
- ›They possess exceptionally long and slender legs.
- ›Their eye arrangement is typically two groups of three eyes, with a possible additional pair.
- ›Pholcids build messy, irregular webs that are not sticky.
- ›Some species exhibit a rapid vibrating or gyrating threat response when disturbed.
- ›Despite a common myth, their venom is not medically significant to humans.
Cellar Spider, Daddy Long-Legs Spider, Carpenter Spider, Daddy Long-Legger, Vibrating Spider, Gyrating Spider, Long Daddy, Angel Spider
Africa, Asia, Europe, North America, South America, Australia, Oceania
- Extremely Long, Thin Legs With Flexible Tarsi
- Eye Arrangement: Two Groups of Three Eyes, Often With A Small Pair In Between
- Hang Inverted In Their Webs
- Envelop Prey With Silk
- Exhibit A Rapid Vibrating/Gyrating Threat Response
- Retreat Or Drop From Web To Escape
- Clean Webs By Removing Prey Remains
About Pholcidae
The Pholcidae family encompasses over 2,000 described species of araneomorph spiders, widely recognized by common names such as cellar spiders, daddy long-legs spiders, and vibrating spiders. First cataloged by Carl Ludwig Koch in 1850, this family is organized into 94 genera and is distributed across the globe, with the exception of Antarctica.
Appearance and Habitat
Pholcids are characterized by their exceptionally long, thin legs and a distinctive eye arrangement consisting of two clusters of three eyes, often supplemented by a small pair situated between them, resulting in a total of six or eight eyes. Their bodies are typically whitish or grey. They construct irregular, non-adhesive webs in dark, sheltered environments like caves, beneath rocks, and in abandoned burrows. In human-made structures, they are commonly found in undisturbed corners, attics, and cellars, which has led to their frequent identification as "cellar spiders."
Behavior and Diet
These spiders employ a unique hunting strategy, relying on the structure of their non-sticky webs to entangle prey. Once detected, prey is rapidly enveloped in silk. Pholcids are known to consume insects but also exhibit kleptoparasitism, invading the webs of other spiders to steal their prey or eggs. A notable behavior is their threat response, where they vibrate rapidly in a gyrating motion. This movement serves multiple proposed purposes, including confusing predators, signaling rivals, or further entangling prey. Despite a persistent myth, the venom of Pholcidae spiders is not medically significant to humans, and their fangs are too small to cause serious harm.
Misconceptions
An enduring urban legend claims that daddy long-legs spiders possess the most potent venom of any spider but are unable to bite humans due to their small fangs. Scientific evidence and expert analysis, including experiments by the television show MythBusters, have debunked this myth. While Pholcidae can bite and their venom is effective against insects, it poses no significant threat to humans. The legend may stem from their known predation on venomous spiders like the redback, leading to a misinterpretation of their own capabilities.
Source: Wikipedia ↗
Frequently Asked Questions
What are the common names for Pholcidae spiders?
Pholcidae spiders are known by several common names, including cellar spider, daddy long-legs spider, carpenter spider, daddy long-legger, vibrating spider, gyrating spider, long daddy, and angel spider. The name 'daddy long-legs' is particularly common but is also used for harvestmen and crane flies.
Where do Pholcidae spiders live?
Pholcids inhabit all continents except Antarctica. They prefer dark and damp locations such as caves, under rocks, loose bark, and abandoned burrows. In human environments, they are often found in undisturbed areas like attics and cellars, earning them the name 'cellar spider'.
What do Pholcidae spiders eat?
Their diet primarily consists of insects caught in their webs. However, some species are known to invade the webs of other spiders to prey on the host, their eggs, or their captured prey. They have been observed to prey on species like funnel weavers, redback spiders, and huntsman spiders.
Are Pholcidae spiders dangerous to humans?
Despite an urban legend, Pholcidae spiders are not dangerous to humans. While they are capable of biting and possess venom, it is not medically significant. Their fangs are also relatively small and weak, and they are not aggressive towards people.
How do Pholcidae spiders hunt?
Pholcids are web builders, but their webs are not adhesive. They trap prey in the irregular structure of their webs. When prey is detected, the spider quickly envelops it with silk. They may also mimic struggling prey to lure other spiders closer to their webs.
What is the 'vibrating spider' behavior?
Some Pholcidae species exhibit a threat response by vibrating rapidly in a gyrating motion within their webs when disturbed. This behavior may help them evade predators, signal rivals, or further entangle prey. This distinctive movement is the origin of the common name 'vibrating spider'.
Related Spider species
Dipluridae
Dipluridae, commonly known as curtain-web spiders, are a family of mygalomorph spiders characterized by two pairs of booklungs and stabbing chelicerae. While historically encompassing genera now moved to other families, the current Dipluridae are primarily found in South America and the Caribbean, known for building messy funnel-webs or silk-lined burrows.
Deinopidae
Deinopidae, commonly known as net-casting spiders, are a family of circumtropical cribellate spiders recognized for their unique hunting strategy. These stick-like spiders catch prey by stretching a specialized web between their front legs and then propelling themselves forward, entangling their victims. Their exceptional night vision, facilitated by large posterior median eyes, allows them to hunt effectively in low-light conditions.
Hypochilidae
Hypochilidae, commonly known as lampshade spiders, represent one of the most primitive lineages within the araneomorph spiders. These long-legged arachnids are characterized by their distinctive "lampshade" style webs, typically constructed under overhangs and within caves. The family is distributed across North America and China, with most species found in mountainous regions.