- female E. atrica at the mouth of her retreat
- Funnel web of an agelenid from Spain
- Agelena labyrinthica female in web
- A. labyrinthica , male (immature)
Funnel weavers Temporal range: | |
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Grass spider ( Agelenopsis sp.), female | |
Hobo spider ( E. agrestis ) | |
Scientific classification | |
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 | |
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]
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]
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.
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]
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]
As of January 2023 [update] , 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]
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. Despite past claims, there is no clear evidence that the hobo spider has venom that is dangerous to humans.
Agelenopsis, commonly known as the American grass spiders, is a genus of funnel weavers 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.
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.
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.
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.
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.
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.
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.
Dwarf sheet spiders (Hahniidae) is a family of araneomorph spiders, first described by Philipp Bertkau in 1878.
Araniella is a genus of orb-weaver spiders first described by R. V. Chamberlin & Wilton Ivie in 1942. The genus includes Araniella cucurbitina, the cucumber green spider.
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".
Eratigena is a genus of spider in the family Agelenidae. Most of its species were moved from the genus Tegenaria in 2013, of which the genus name is an anagram. Two species that frequently build webs in and around human dwellings are now placed in this genus: the hobo spider, native to Europe and Central Asia and introduced to North America, and the giant house spider, native to Europe and also introduced into North America.
Barronopsis is a genus of funnel weavers first described by R. V. Chamberlin and 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.
Persiscape is a genus of funnel weavers first described by Alireza Zamani and Yuri M. Marusik in 2020.