Pholcidae
Temporal range:
Pholcus phalangioides
Close-up of a cellar spider's cephalothorax, showing two groups of three clustered eyes
Scientific classification Edit this classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Pholcidae
C. L. Koch, 1850
Diversity
94 genera, 1820 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 skull 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

Pholcids are thin and delicate arachnids. The body, resembling the shape of a peanut, is approximately 2–10 mm (0.08–0.39 inch) in length, and the legs may be up to 50 mm (1.97 inches) long. Pholcus and Smeringopus have cylindrical abdomens and eyes arranged in two lateral groups of three and two smaller median contiguous eyes. Arrangements of eight and six eyes both occur in this family. Spermophora has a small globose abdomen and its eyes are arranged in two groups of three without median eyes. Pholcids are gray to brown, sometimes clear, with banding or chevron markings.

Identification

These spiders have legs roughly 4 times as large as their bodies, making them look quite a lot like harvestmen (Opiliones). But they can be easily differentiated by the two segments, that members of this family have, while harvestmen have fused segments.[3] They can be further distinguished by their irregular structure, and usually brown, tan or grey coloration.

Habitat

Pholcids are found in every continent in the world except Antarctica. 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".[4]

Behavior

Trapping

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.

Threat response

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.[5] If the spider continues to be disturbed it will retreat into a corner or drop from its web and escape.

Diet

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.[6][7]

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.[8] They have also been observed to feed on the spider Steatoda nobilis in countries like Ireland and England.[9]

Gait

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.

Misconceptions

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. Pholcidae are indeed capable of biting humans and 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.[10] According to Rick Vetter of the University of California, Riverside, the daddy long-legs spider has never harmed a human, and there is no evidence that they are dangerous to humans.[11]

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.[12] 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.[13]

Mythbusters experiment

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 whereby 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.[14] Additionally, recent research has shown that pholcid venom is relatively weak in its effects on insects.[15]

Genera

As of April 2019, the World Spider Catalog accepted the following genera:[2]

  • Aetana Huber, 2005  Asia, Fiji
  • Anansus Huber, 2007  Africa
  • Anopsicus Chamberlin & Ivie, 1938  Mexico, Ecuador, Caribbean, Central America
  • Apokayana Huber, 2018  Malaysia, Indonesia
  • Arenita Huber & Carvalho, 2019  Brazil
  • Arnapa Huber, 2019  Indonesia, Papua New Guinea
  • Artema Walckenaer, 1837  Asia, Africa
  • Aucana Huber, 2000  Chile
  • Aymaria Huber, 2000  South America
  • Belisana Thorell, 1898  Asia, Oceania
  • Blancoa Huber, 2000  Venezuela
  • Buitinga Huber, 2003  Africa
  • Calapnita Simon, 1892  Asia
  • Canaima Huber, 2000  Trinidad, Venezuela
  • Cantikus Huber, 2018  Asia
  • Carapoia González-Sponga, 1998  South America
  • Cenemus Saaristo, 2001  Seychelles
  • Chibchea Huber, 2000  South America
  • Chisosa Huber, 2000  Mexico, Aruba, United States
  • Ciboneya Pérez, 2001  Cuba
  • Coryssocnemis Simon, 1893  Trinidad, South America, Mexico, Central America
  • Crossopriza Simon, 1893  Asia, Africa, United States, Venezuela, Germany, Australia
  • Enetea Huber, 2000  Bolivia
  • Galapa Huber, 2000  Ecuador
  • Gertschiola Brignoli, 1981  Argentina
  • Giloloa Huber, 2019  Indonesia
  • Guaranita Huber, 2000  Argentina, Brazil
  • Hantu Huber, 2016  Indonesia
  • Holocneminus Berland, 1942  Asia, Samoa
  • Holocnemus Simon, 1873  Spain, Italy, Portugal
  • Hoplopholcus Kulczyński, 1908  Asia, Greece
  • Ibotyporanga Mello-Leitão, 1944  Brazil
  • Ixchela Huber, 2000  Mexico, Central America
  • Kairona Huber & Carvalho, 2019  Brazil
  • Kambiwa Huber, 2000  Brazil
  • Kelabita Huber, 2018  Indonesia, Malaysia
  • Khorata Huber, 2005  Asia
  • Kintaqa Huber, 2018  Thailand, Malaysia
  • Leptopholcus Simon, 1893  Asia, Africa
  • Litoporus Simon, 1893  South America
  • Magana Huber, 2019  Oman
  • Mecolaesthus Simon, 1893  Caribbean, South America
  • Meraha Huber, 2018  Asia
  • Mesabolivar González-Sponga, 1998  South America, Trinidad
  • Metagonia Simon, 1893  North America, South America, Central America, Caribbean
  • Micromerys Bradley, 1877  Papua New Guinea, Australia
  • Micropholcus Deeleman-Reinhold & Prinsen, 1987  Morocco, Caribbean, Europe, Asia, Australia
  • Modisimus Simon, 1893  North America, Central America, Caribbean, Germany, Seychelles, Asia, Australia, South America
  • Muruta Huber, 2018  Malaysia
  • Nerudia Huber, 2000  Chile, Argentina
  • Ninetis Simon, 1890  Africa, Yemen
  • Nipisa Huber, 2018  Asia
  • Nita Huber & El-Hennawy, 2007  Egypt, Iran, Uzbekistan
  • Nyikoa Huber, 2007  Central Africa
  • Ossinissa Dimitrov & Ribera, 2005  Canary Is.
  • Otavaloa Huber, 2000  South America
  • Paiwana Huber, 2018  Taiwan
  • Panjange Deeleman-Reinhold & Deeleman, 1983  Asia, Oceania
  • Papiamenta Huber, 2000  Curaçao
  • Paramicromerys Millot, 1946  Madagascar
  • Pehrforsskalia Deeleman-Reinhold & van Harten, 2001  Africa, Asia
  • Pemona Huber, 2019  Venezuela
  • Pholcophora Banks, 1896  United States, Canada, Mexico
  • Pholcus Walckenaer, 1805  Asia, Europe, Africa, United States, Oceania
  • Physocyclus Simon, 1893  North America, South America, Czech Republic, Asia, Australia, Central America
  • Pinocchio Huber & Carvalho, 2019  Brazil
  • Pisaboa Huber, 2000  Peru, Venezuela, Bolivia
  • Pomboa Huber, 2000  Colombia
  • Pribumia Huber, 2018  Asia
  • Priscula Simon, 1893  South America
  • Psilochorus Simon, 1893  North America, South America, Asia, New Zealand
  • Quamtana Huber, 2003  Africa
  • Queliceria González-Sponga, 2003  Venezuela
  • Saciperere Huber & Carvalho, 2019  Brazil
  • Savarna Huber, 2005  Thailand, Malaysia, Indonesia
  • Smeringopina Kraus, 1957  Africa
  • Smeringopus Simon, 1890  Africa, Asia, Australia
  • Spermophora Hentz, 1841  Africa, Asia, Oceania, Germany, Brazil, United States
  • Spermophorides Wunderlich, 1992  Africa, Europe
  • Stenosfemuraia González-Sponga, 1998  Venezuela
  • Stygopholcus Absolon & Kratochvíl, 1932  Croatia, Greece, Montenegro
  • Systenita Simon, 1893  Venezuela
  • Tainonia Huber, 2000  Hispaniola
  • Teranga Huber, 2018  Indonesia, Philippines
  • Tibetia Zhang, Zhu & Song, 2006  Tibet
  • Tissahamia Huber, 2018  Asia
  • Tolteca Huber, 2000  Mexico
  • Trichocyclus Simon, 1908  Australia
  • Tupigea Huber, 2000  Brazil
  • Uthina Simon, 1893  Asia, Seychelles
  • Wanniyala Huber & Benjamin, 2005  Sri Lanka
  • Waunana Huber, 2000  Colombia, Ecuador, Panama
  • Wugigarra Huber, 2001  Australia
  • Zatavua Huber, 2003  Madagascar

References

Citations

  1. Koch, C. L. (1850). Übersicht des Arachnidensystems. doi:10.5962/bhl.title.39561.
  2. 1 2 "Family: Pholcidae C. L. Koch, 1850". World Spider Catalog. Natural History Museum Bern. Retrieved 2019-04-23.
  3. "Pholcidae - Bugwoodwiki". wiki.bugwood.org. Retrieved 2022-08-09.
  4. "Pholcidae information". BioKIDS – Kids' Inquiry of Diverse Species. Animal Diversity Web. Retrieved 15 July 2018.
  5. Marlin, Bruce (25 April 2006). Video of the "vibrating spider" vibrating (QuickTime Movie).
  6. "Daddy Long Legs". Queensland Museum.
  7. Wim van Egmond. "Pholcus phalangioides, the daddy-long-legs spider, in 3D".
  8. "Pholcus phalangioides (Long-bodied Cellar Spider) – Spider Identification & Pictures". spiderid.com. Retrieved 2018-07-15.
  9. 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.
  10. "Daddy Long Legs Site on UCR". Archived from the original on 2013-11-04. Retrieved 2007-09-15.
  11. "Spider Myths – Daddy Long Legs". Archived from the original on 2013-11-04. Retrieved 2007-09-15.
  12. "Family Pholcidae – daddy long-leg spiders". Brisbane Insects and Spiders. 2009. Retrieved 13 November 2009.
  13. "Daddy long-legs".
  14. "Daddy long-leg spiders". Myth Files. Discovery channel. Archived from the original on April 12, 2011.
  15. "The Spider Myths Site". Burke Museum. 12 May 2005. Archived from the original on 14 July 2007. Retrieved 7 November 2007.

General bibliography

  • 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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