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Pholcidae

From Wikipedia, the free encyclopedia
(Redirected from Cellar spider)
"Daddy longlegs spider" redirects here; not to be confused with Opiliones or Crane fly.
Not to be confused with Phocides, a genus of butterflies, or Phocidae, a family of seals.

Pholcidae
Temporal range: Palaeogene–present
female Smeringopus natalensis with eggs
male Pholcus phalangioides
Scientific classification Edit this classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Pholcidae
C. L. Koch, 1850
Diversity
97 genera, c. 2,000 species
Estimated range of Pholcidae.

The Pholcidae are a family of araneomorph spiders. The family contains more than 1,800 individual species of pholcids, including those commonly known as cellar spider, daddy long-legs spider, carpenter spider, daddy long-legger, vibrating spider, gyrating spider, long daddy, and angel spider. The family, first described by Carl Ludwig Koch in 1850,[1] is divided into 94 genera.[2]

The common name "daddy long-legs" is used for several species, especially Pholcus phalangioides, but is also the common name for several other arthropod groups, including harvestmen and crane flies.

Appearance

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Pholcids have extremely long and thin legs with flexible tarsi.[3][4] They can be distinguished from other long-legged spiders by the eye arrangement: Pholcidae have two groups of three eyes each, and there may be a pair of small eyes in between them.[3] Most have this middle pair present for a total of eight eyes, but some genera (e.g. Modisimus, Spermophora, Spermophorides) lack this pair and have a total of six eyes.[5] The body is often whitish or grey in colour.[4] Harvestmen (Opiliones), which share the name "daddy longlegs", also have long and thin legs but have only one pair of eyes, and their body appears to be a single segment.[6]

Like other spiders, pholcids have two body segments, the prosoma and opisthosoma. The prosoma may be evenly domed (e.g. Pholcus, Micropholcus) or have a furrow or pit in the middle.[5] The opisthosoma may be long and cylindrical (e.g. Pholcus, Holocnemus), long and pointed dorso-posteriorly (e.g. Crossopriza) or short (e.g. Micropholcus).[5]

There is variation in size, ranging from just over 1 millimetre (Spermophorides lascars) to 11 mm (Artema atlanta) in body length.[7]

Habitat

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Two Crossopriza lyoni. The bottom one is male. The female is clutching her egg bundle

Pholcids are found in every continent in the world, except Antarctica.[8] Pholcids hang inverted in their messy and irregular-shaped webs. These webs are constructed in dark and damp recesses such as in caves, under rocks and loose bark, and in abandoned mammal burrows. In areas of human habitation pholcids construct webs in undisturbed areas in buildings such as high corners, attics and cellars, hence the common name "cellar spider".[9]

Behavior

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Cellar spider vibrating rapidly in response to a threat

Trapping

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The web of pholcids has no adhesive properties and instead relies on its irregular structure to trap prey. When pholcid spiders detect prey within their webs the spiders quickly envelop prey with silk-like material. The prey may be eaten immediately or stored for later. When finished feeding they will clean the web by unhooking the remains of the prey and letting the carcass drop from the web. They are passive against humans.[citation needed]

Threat response

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Some species of Pholcidae exhibit a threat response when disturbed by a touch to the web or entangled large prey. The arachnid responds by vibrating rapidly in a gyrating motion in its web, which may sometimes fall into a circular rhythm. It may oscillate in tune with the elasticity of the web causing an oscillation larger than the motion of the spider's legs. While other species of spider exhibit this behaviour, such behavior by the Pholcidae species has led to these spiders sometimes being called "vibrating spiders". There are several proposed reasons for this threat response. The movement may make it difficult for a predator to locate or strike the spider, or may be a signal to an assumed rival to leave. Vibrating may also increase the chances of capturing insects that have just brushed their web and are still hovering nearby, or further entangle prey that may have otherwise been able to free itself.[10] If the spider continues to be disturbed it will retreat into a corner or drop from its web and escape.

Diet

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Male shortbodied cellar spider (Spermophora senoculata) from the United States

Although they do eat insects, certain species of these spiders invade webs of other spiders to eat the host, the eggs, or the prey. In some cases the spider vibrates the web of other spiders, mimicking the struggle of trapped prey to lure the host closer. Pholcids prey on Tegenaria funnel weaver spiders, and are known to attack and eat redback spiders, huntsman spiders and house spiders.[11][12]

A cellar spider has captured a much more robust looking house spider, by snaring it in its silk. This picture was taken in a domestic setting. The predator spider has noticeably grown in abdomen size whilst the prey appears diminished.
A cellar spider which has captured a house spider, in a domestic setting. The predator spider has noticeably grown in abdomen size during feeding, whilst the prey appears diminished.

Pholcids may be beneficial to humans living in regions with dense hobo spider populations as predation on Tegenaria may keep populations in check.[13] They have also been observed to feed on the spider Steatoda nobilis in countries like Ireland and England.[14]

Gait

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Pholcus phalangioides often uses an alternating tetrapod gait (first right leg, then second left leg, then third right leg, etc.), which is commonly found in many spider species. However, frequent variations from this pattern have been documented during observations of the spiders' movements.[15]

Misconceptions

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There is an urban legend that daddy long-legs spiders have the most potent venom of any spider but that their fangs are either too small or too weak to puncture human skin; the same legend is also repeated of the harvestman and crane fly, also known as daddy long-legs in some regions. This is not true for any of the three. While Pholcidae are indeed capable of biting humans, their venom is not medically significant, and neither harvestmen nor crane flies have any venom or fangs to speak of. Indeed, pholcid spiders do have a short fang structure (called uncate due to its "hooked" shape). Brown recluse spiders also have uncate fang structure, but are able to deliver medically significant bites.

Possible explanations include: pholcid venom is not toxic to humans; pholcid uncate are smaller than those of brown recluse; or there is a musculature difference between the two arachnids, with recluses, being hunting spiders, possessing stronger muscles for fang penetration.[16] According to Rick Vetter of the University of California, Riverside, the daddy long-legs spider has never harmed a human physically, and there is no evidence that they are dangerous to humans.[17]

The legend may result from the fact that the daddy long-legs spider preys upon deadly venomous spiders, such as the redback, and other members of the true widow genus Latrodectus.[18] To the extent that such arachnological information was known to the general public, it was perhaps thought that if the daddy long-legs spider could kill a spider capable of delivering fatal bites to humans, then it must be more venomous, and the uncate fangs were regarded as prohibiting it from killing people. In reality, it is able to cast lengths of silk onto its prey, incapacitating them from a safe distance.[19]

Mythbusters experiment

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During 2004, the Discovery Channel television show MythBusters tested the daddy long-legs venom myth in episode 13, "Buried in Concrete". Hosts Jamie Hyneman and Adam Savage first established that the spider's venom was not as toxic as other venoms, after being told about an experiment wherein mice were injected with venom from both a daddy long-legs and a black widow, with the black widow venom producing a much stronger reaction. After measuring the spider's fangs at approximately 0.25 mm, Adam Savage inserted his hand into a container with several daddy-long-legs, and reported that he felt a bite which produced a mild, short-lived burning sensation. The bite did in fact penetrate his skin, but did not cause any notable harm.[20] Additionally, recent research has shown that pholcid venom is relatively weak in its effects on insects.[21]

Daddy-Long-Legs

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The colloquial name daddy-long-legs is often used to refer to Pholcidae, harvestmen, and crane flies. This name originates in Faroese as "lokki~grindalokki~grindalokkur" which literally translates to "daddy-long-legs". It is likely a kenning and more accurately translates to "grandfather of web spinners" as it refers to the Nordic god Loki who was associated with spiders in folklore.[22]

Genera

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As of October 2025, this family includes 97 genera:[2]

Relationships

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References

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Citations

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  1. ^ Koch, C. L. (1850). Übersicht des Arachnidensystems. doi:10.5962/bhl.title.39561.
  2. ^ a b "Family: Pholcidae C. L. Koch, 1850". World Spider Catalog. doi:10.24436/2. Retrieved 2025-10-18.
  3. ^ a b "araneae - Key to families". araneae.nmbe.ch. Retrieved 2024-02-02.
  4. ^ a b "Family Pholcidae - Cellar Spiders". bugguide.net. Retrieved 2024-02-02.
  5. ^ a b c "araneae - Pholcidae". araneae.nmbe.ch. Retrieved 2024-02-02.
  6. ^ "Opiliones - harvestmen". www.ento.csiro.au. Retrieved 2024-02-02.
  7. ^ Saaristo, M. I. (2001). "Pholcid spiders of the granitic Seychelles (Araneae, Pholcidae)" (PDF). Phelsuma. 9: 9–28.
  8. ^ "British Antarctic Survey".
  9. ^ "Pholcidae information". BioKIDS – Kids' Inquiry of Diverse Species. Animal Diversity Web. Retrieved 15 July 2018.
  10. ^ Marlin, Bruce (25 April 2006). Video of the "vibrating spider" vibrating (QuickTime Movie).
  11. ^ "Daddy Long Legs". Queensland Museum.
  12. ^ Wim van Egmond. "Pholcus phalangioides, the daddy-long-legs spider, in 3D".
  13. ^ "Pholcus phalangioides (Long-bodied Cellar Spider) – Spider Identification & Pictures". spiderid.com. Retrieved 2018-07-15.
  14. ^ Dugon, Michel M.; Dunbar, John P.; Afoullouss, Sam; Schulte, Janic; McEvoy, Amanda; English, Michael J.; Hogan, Ruth; Ennis, Collie; Sulpice, Ronan (2017). "Occurrence, reproductive rate and identification of the non-native Noble false widow spider Steatoda nobilis (Thorell, 1875) in Ireland". Biology and Environment: Proceedings of the Royal Irish Academy. 117B (2): 77–89. doi:10.3318/bioe.2017.11. ISSN 0791-7945. JSTOR 10.3318/bioe.2017.11. S2CID 90738542.
  15. ^ Hao, Xin; Ma, Wenxing; Liu, Chunbao; Li, Yilei; Qian, Zhihui; Ren, Luquan; Ren, Lei (2019). "Analysis of Spiders' Joint Kinematics and Driving Modes under Different Ground Conditions". Applied Bionics and Biomechanics. 2019 4617212. doi:10.1155/2019/4617212. ISSN 1176-2322. PMC 6935789. PMID 31929827.
  16. ^ "Daddy Long Legs Site on UCR". Archived from the original on 2013-11-04. Retrieved 2007-09-15.
  17. ^ "Spider Myths – Daddy Long Legs". Archived from the original on 2013-11-04. Retrieved 2007-09-15.
  18. ^ "Family Pholcidae – daddy long-leg spiders". Brisbane Insects and Spiders. 2009. Retrieved 13 November 2009.
  19. ^ "Daddy long-legs".
  20. ^ "Daddy long-leg spiders". Myth Files. Discovery channel. Archived from the original on April 12, 2011.
  21. ^ "The Spider Myths Site". Burke Museum. 12 May 2005. Archived from the original on 14 July 2007. Retrieved 7 November 2007.
  22. ^ Heide, Eldar (January 2011). "Loki, the Vätte, and the Ash Lad: A Study Combining Old Scandinavian and Late Material". Viking and Medieval Scandinavia. 7: 63–106. doi:10.1484/J.VMS.1.102616. ISSN 1782-7183.

General bibliography

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  • Pinto-da-Rocha, R.; Machado, G.; Giribet, G., eds. (2007). Harvestmen: The Biology of Opiliones. Harvard University Press. ISBN 978-0-674-02343-7.
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