Agelenidae

Last updated

Funnel weavers
Temporal range: Eocene–Recent
Grass spider (Agelenopsis naevia).JPG
Grass spider ( Agelenopsis sp.), female
Tegenaria agrestis 070903.jpg
Hobo spider ( E. agrestis )
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Chelicerata
Class: Arachnida
Order: Araneae
Infraorder: Araneomorphae
Family: Agelenidae
C. L. Koch, 1837
Diversity
92 genera, 1374 species
Distribution.agelenidae.1.png

The Agelenidae are a large family of spiders in the suborder Araneomorphae. Well-known examples include the common "grass spiders" of the genus Agelenopsis . Nearly all Agelenidae are harmless to humans, but the bite of the hobo spider (Eratigena agrestis) may be medically significant, and some evidence suggests it might cause necrotic lesions, [1] but the matter remains subject to debate. [2] The most widely accepted common name for members of the family is funnel weaver. [3]

Contents

Description

The body length of the smallest Agelenidae spiders are about 4 mm (0.16 in), excluding the legs, while the larger species grow to 20 mm (0.79 in) long. Some exceptionally large species, such as Eratigena atrica , may reach 5 to 10 cm (2.0 to 3.9 in) in total leg span.

Agelenids have eight eyes in two horizontal rows of four. Their cephalothoraces narrow somewhat towards the front where the eyes are. Their abdomens are more or less oval, usually patterned with two rows of lines and spots. Some species have longitudinal lines on the dorsal surface of the cephalothorax, whereas other species do not; for example, the hobo spider does not, which assists in informally distinguishing it from similar-looking species. [4]

Biology

Female Agelena labyrinthica in her web funnel in Belgium. Labyrinth spider (Agelena labyrinthica) female in web funnel.jpg
Female Agelena labyrinthica in her web funnel in Belgium.

Most of the Agelenidae are very fast runners, especially on their webs. With speeds clocked at 1.73 ft/s (0.53 m/s), the giant house spider held the Guinness Book of World Records title for top spider speed until 1987. A recent literature review found peer-reviewed accounts of several agelenid species achieving speeds in this range, though some other taxa have achieved higher speeds. [5] [6]

Agelenids build a flat sheet of nonsticky web with a funnel-shaped retreat to one side or occasionally in the middle, depending on the situation and species. Accordingly, "funnel weaver" is the most widely accepted common name for members of the family, but they should not be confused with the so-called "funnel-web tarantulas" or "funnel-web spiders" of mygalomorph families. [3]

The typical hunting mode for most sheet-building Agelenidae is similar to that of most other families of spiders that build sheet webs in the open, typically on grass or in scrubland as opposed to under bark, rocks, and the like. They await the arrival of prey such as grasshoppers that fall onto the horizontal web. Although the web is not sticky, it is full of entangling filaments that the spider continually lays down when passing over. The filaments catch in the least projections on a prey insect's body or limbs. The web also is springy, and whether perching on the sheet or awaiting prey in its retreat, the spider reacts immediately to vibrations, whether from a courting male, the threatening struggles of dangerous invaders, or the weaker struggles of potential meals. They attack promising prey by rushing out at high speed and dealing a paralysing venomous bite. The agatoxin in their venom has been studied extensively in Agelenopsis aperta. [7] Once the prey has been disabled, the spider generally drags it back into the retreat and begins to feed. This method of attack is consistent with the high speeds at which the Agelenidae run. Other sheet-web hunters such as some Pisauridae also are very fast runners.

Like any fast-running spider, the Agelenidae possess good vision, and are generally photosensitive (i.e. react to changes in the light), so they can successfully retreat upon perceiving a larger threat's shadow approaching. Some are also sensitive to wind blows, and can retreat before the prey even spots them. Males are less successful ambushers than females, so prefer to roam around and wander to new areas, rather than stay in one single web. In September, males of outdoors species (such as Agelenopsis and Agelena) can seek refuge within houses, usually nesting on or underneath outer windowsills, or also around the porch door. These spiders often are neither pest controllers nor pests themselves; they are very selective in their prey, and do not consume large quantities; also, they are immune to intimidation and come back to their webs even after being disturbed, unless they are completely destroyed.

Parasocial species

The type genus, Agelena, includes some parasocial spiders that live in complex communal webs in Africa. The best known of these is probably A. consociata. Social behaviour in these spiders comprises communal web-building, cooperative prey capture, and communal rearing of young. No trophallaxis occurs, though, nor does any true eusociality such as occurs in the social Hymenoptera (ants, bees, and wasps); for example, the spiders have no castes such as sterile workers or soldiers, and all females are reproductive. [8]

Medical significance

Only one species of agelenid has become prominent as a putative cause of a significant frequency of necrotic arachnidism; this is the hobo spider, Eratigena agrestis. [4] This perception arose when the species was accidentally introduced to the United States in the mid-20th century and propagated rapidly in several regions. It is a fairly large, rapidly moving spider, so accordingly alarms many people. [9] A few cases of bites have been reported in Southern California by the desert grass spider, Agelenopsis aperta, that resulted in symptoms, but determining whether these cases were confused with similar-looking spiders is difficult. [10]

Genera

As of January 2023, the World Spider Catalog accepts these genera: [11]

A number of fossil species are known from Eocene aged Baltic amber, but their exact relationship with extant members of the clade is unclear. [12]

See also

Related Research Articles

<span class="mw-page-title-main">Hobo spider</span> Species of spider

The hobo spider is a member of the family of spiders known colloquially as funnel web spiders, but not to be confused with the Australian funnel-web spider. Individuals construct a funnel-shaped structure of silk sheeting and lie in wait at the small end of the funnel for prey insects to blunder onto their webs. Hobo spiders sometimes build their webs in or around human habitations. The hobo spider lays its eggs in September and they hatch during late spring. After the male hobo spider mates it dies.

<i>Agelenopsis</i> Genus of spiders

Agelenopsis, commonly known as the American grass spiders, is a genus of funnel weavers first described by C.G. Giebel in 1869. They weave sheet webs that have a funnel shelter on one edge. The web is not sticky, but these spiders make up for that by running very rapidly. The larger specimens can grow to about 19 mm in body length. They may be recognized by the arrangement of their eight eyes into three rows. The top row has two eyes, the middle row has four eyes, and the bottom row has two eyes. They have two prominent hind spinnerets, somewhat indistinct bands on their legs, and two dark bands running down either side of the cephalothorax.

<span class="mw-page-title-main">Ground spider</span> Family of spiders

Ground spiders comprise Gnaphosidae, the seventh largest spider family with over 2,000 described species in over 100 genera distributed worldwide. There are 105 species known to central Europe, and common genera include Gnaphosa, Drassodes, Micaria, Cesonia, Zelotes and many others. They are closely related to Clubionidae. At present, no ground spiders are known to be seriously venomous to humans.

<span class="mw-page-title-main">Linyphiidae</span> Family of spiders

Linyphiidae, spiders commonly known as sheet weavers, or money spiders is a family of very small spiders comprising 4706 described species in 620 genera worldwide. This makes Linyphiidae the second largest family of spiders after the Salticidae. The family is poorly understood due to their small body size and wide distribution; new genera and species are still being discovered throughout the world. The newest such genus is Himalafurca from Nepal, formally described in April 2021 by Tanasevitch. Since it is so difficult to identify such tiny spiders, there are regular changes in taxonomy as species are combined or divided.

<i>Tegenaria</i> Genus of spiders

Tegenaria is a genus of fast-running funnel weavers that occupy much of the Northern Hemisphere except for Japan and Indonesia. It was first described by Pierre André Latreille in 1804, though many of its species have been moved elsewhere. The majority of these were moved to Eratigena, including the giant house spider and the hobo spider.

<span class="mw-page-title-main">Amaurobiidae</span> Family of spiders

Amaurobiidae is a family of three-clawed cribellate or ecribellate spiders found in crevices and hollows or under stones where they build retreats, and are often collected in pitfall traps. Unlidded burrows are sometimes quite obvious in crusty, loamy soil. They are difficult to distinguish from related spiders in other families, especially Agelenidae, Desidae and Amphinectidae. Their intra- and interfamilial relationships are contentious. According to the World Spider Catalog, 2023, the family Amaurobiidae includes 286 species in 50 genera.

<span class="mw-page-title-main">Giant house spider</span> Species of spider

The giant house spider has been treated as either one species, under the name Eratigena atrica, or as three species, E. atrica, E. duellica and E. saeva. As of April 2020, the three species view was accepted by the World Spider Catalog. They are among the largest spiders of Central and Northern Europe. They were previously placed in the genus Tegenaria. In 2013, they were moved to the new genus Eratigena as the single species Eratigena atrica. In 2018, the three separate species were restored. The bite of these species does not pose a threat to humans or pets, and they are generally reluctant to bite, preferring instead to hide or escape.

<span class="mw-page-title-main">Dictynidae</span> Family of spiders

Dictynidae is a family of cribellate, hackled band-producing spiders first described by Octavius Pickard-Cambridge in 1871. Most build irregular webs on or near the ground, creating a tangle of silken fibers among several branches or stems of one plant.

<i>Pireneitega</i> Genus of spiders

Pireneitega is a genus of funnel weavers first described by Kyukichi Kishida in 1955.

Agelena gaerdesi is a species of spider in the family Agelenidae, which contains at least 1,315 species of funnel-web spiders as of August 2021. It was first described by Roewer, in 1955. It is primarily found in Namibia.

<i>Coelotes</i> Genus of spiders

Coelotes is a genus of funnel weavers first described by John Blackwall in 1841. A large number of species are found throughout Europe and Asia.

<i>Cicurina</i> Genus of spiders

Cicurina, also called the cave meshweaver, is a genus of dwarf sheet spiders that was first described by Anton Menge in 1871. Originally placed with the funnel weavers, it was moved to the Dictynidae in 1967, then to the Hahniidae in 2017. The name is from the Latin root "cucur-", meaning "to tame".

Agelena cuspidata is a species of spider in the family Agelenidae, which contains at least 1,315 species of funnel-web spiders as of August 2021. It was first described by Zhang, Zhu & Song, in 2005. It is primarily found in China.

<i>Eratigena</i> Genus of spiders

Eratigena is a genus of spider in the family Agelenidae. Most of its species were moved from the genus Tegenaria in 2013. Which is what this genus is named after, being an anagram of Tegenaria. Two species that frequently build webs in and around human dwellings are now placed in this genus. Eratigena agrestis is the hobo spider, native to Europe and Central Asia, introduced to North America. Eratigena atrica is the giant house spider, native to Europe and also introduced into North America.

Calilena is a genus of North American funnel weavers first described by R. V. Chamberlin & Wilton Ivie in 1941.

Tortolena is a genus of North American and Central American funnel weavers first described by R. V. Chamberlin & Wilton Ivie in 1941. As of April 2019 it contains only two species.

References

  1. Goddard, Jerome (3 December 2012). Physician's Guide to Arthropods of Medical Importance (6th ed.). CRC Press. p. 380. ISBN   978-1-4398-5085-5 via Google Books.
  2. Gaver-Wainwright, Melissa M.; Zack, Richard S.; Foradori, Matthew J.; Lavine, Laura Corley (2011). "Misdiagnosis of Spider Bites: Bacterial Associates, Mechanical Pathogen Transfer, and Hemolytic Potential of Venom from the Hobo Spider, Eratigena agrestis (Araneae: Agelenidae)". Journal of Medical Entomology. 48 (2): 382–388. doi: 10.1603/ME09224 . PMID   21485377.
  3. 1 2 Breene; et al. (2003). Common Names of Arachnids (PDF) (5th ed.). Archived from the original (PDF) on 2006-09-27. Retrieved 2006-09-27.
  4. 1 2 Vetter, R. S., and A. L. Antonelli. 2002. How to identify (or misidentify) the hobo spider. Wash. St. Coop. Ext. Pest Leafl. Series No. 116
  5. Spagna, J. C.; Peattie, A. M. (2012). "Terrestrial locomotion in arachnids". Journal of Insect Physiology. 58 (5): 599–606. doi:10.1016/j.jinsphys.2012.01.019. PMID   22326455.
  6. Gorb, S.N.; Barth, F.G. (1994). "Locomotor behavior during prey-capture of a fishing spider, Dolomedes plantarius (Araneae: Araneidae): galloping and stopping". The Journal of Arachnology. 22: 89–93.
  7. Adams, Michael E. (April 2004). "Agatoxins: ion channel specific toxins from the american funnel web spider, Agelenopsis aperta". Toxicon. 43 (5): 509–525. doi:10.1016/j.toxicon.2004.02.004. ISSN   0041-0101. PMID   15066410.
  8. Rainer Foelix (3 December 2010). Biology of Spiders. Oxford University Press, USA. pp. 320–. ISBN   978-0-19-981324-7.
  9. Vetter, Richard S.; Isbister, Geoffrey K. (December 2004). "Do Hobo Spider Bites Cause Dermonecrotic Injuries?". Annals of Emergency Medicine . 44 (6): 605–7. doi:10.1016/j.annemergmed.2004.03.016. PMID   15573036.
  10. Vetter, Richard S (December 1998). "Envenomation by a spider, Agelenopsis aperta (Family: Agelenidae) Previously Considered Harmless". Annals of Emergency Medicine. 32 (6): 739–741. doi:10.1016/s0196-0644(98)70076-9. ISSN   0196-0644. PMID   9832673.
  11. "Family: Agelenidae C. L. Koch, 1837". World Spider Catalog. Natural History Museum Bern. Archived from the original on 2023-01-19. Retrieved 2023-01-19.
  12. Magalhaes, Ivan L. F.; Azevedo, Guilherme H. F.; Michalik, Peter; Ramírez, Martín J. (February 2020). "The fossil record of spiders revisited: implications for calibrating trees and evidence for a major faunal turnover since the Mesozoic". Biological Reviews. 95 (1): 184–217. doi:10.1111/brv.12559. ISSN   1464-7931. PMID   31713947. S2CID   207937170.

Further reading