Dwarf spider
Encyclopedia
Erigoninae are the largest subfamily of sheet weavers (Linyphiidae), which is itself the second largest spider family. In the United States
they are known as dwarf spiders, while they are called money spiders in England
. The exact taxonomic
limits of the subfamily are not yet known.
Erigoninae are the most numerous of the sheet weavers, with more than 2,000 described species.
Many species live in leaf litter and build minute sheet webs.
These spiders probably are more important as members of the beneficial complex of predators in agroecosystems than is generally known.
One species, Atypena formosana lives in colonies in wetland habitats, where it builds nets just above the water line in rice fields to hunt planthopper
nymph
s.
The most well-known genus is Erigone
.
s that balloon
both as spiderling
s and adults.
Many males have bizarre projections on their carapace
s, including lobes, turret
s, grooves, pits and modified hairs. The function of these projections is little understood, but is presumed to be involved with courtship. In a few species the females have been observed to grip the males by the pits or grooves during copulation, using their cheliceres. They later ingested secretions produced by the male prosomic glands after depositing saliva-like fluid on them.
While they are the dominant spider group of the temperate and cold regions of the Northern Hemisphere they are less diverse in the Southern Hemisphere No native species have been found from New Zealand
and Australia
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
they are known as dwarf spiders, while they are called money spiders in England
England
England is a country that is part of the United Kingdom. It shares land borders with Scotland to the north and Wales to the west; the Irish Sea is to the north west, the Celtic Sea to the south west, with the North Sea to the east and the English Channel to the south separating it from continental...
. The exact taxonomic
Taxonomy
Taxonomy is the science of identifying and naming species, and arranging them into a classification. The field of taxonomy, sometimes referred to as "biological taxonomy", revolves around the description and use of taxonomic units, known as taxa...
limits of the subfamily are not yet known.
Erigoninae are the most numerous of the sheet weavers, with more than 2,000 described species.
Many species live in leaf litter and build minute sheet webs.
These spiders probably are more important as members of the beneficial complex of predators in agroecosystems than is generally known.
One species, Atypena formosana lives in colonies in wetland habitats, where it builds nets just above the water line in rice fields to hunt planthopper
Planthopper
A planthopper is any insect in the infraorder Fulgoromorpha within the Hemiptera. The name comes from their remarkable resemblance to leaves and other plants of their environment and from the fact that they often "hop" for quick transportation in a similar way to that of grasshoppers. However,...
nymph
Nymph (biology)
In biology, a nymph is the immature form of some invertebrates, particularly insects, which undergoes gradual metamorphosis before reaching its adult stage. Unlike a typical larva, a nymph's overall form already resembles that of the adult. In addition, while a nymph moults it never enters a...
s.
The most well-known genus is Erigone
Erigone (genus)
Erigone is a genus of spiders of the araneomorphae sub-order and the Linyphiidae family. They are carnivorous, preying on small insects such as psylla and flies. The species of the genus are native to America, Europe, Asia, Africa and Oceania...
.
Description
Most are very small (some less than 1 mm, very few up to 6 mm) spiderSpider
Spiders are air-breathing arthropods that have eight legs, and chelicerae with fangs that inject venom. They are the largest order of arachnids and rank seventh in total species diversity among all other groups of organisms...
s that balloon
Ballooning (spider)
Ballooning is a term used for the mechanical kiting that many spiders, especially small species, as well as certain mites and some caterpillars use to disperse through the air. Many small spiders use gossamer or especially fine silk to lift themselves off a surface or use the silk as an anchor in...
both as spiderling
Spiderling
Spiderling may refer to:* an immature spider* the herbaceous plant genus Boerhavia...
s and adults.
Many males have bizarre projections on their carapace
Carapace
A carapace is a dorsal section of the exoskeleton or shell in a number of animal groups, including arthropods such as crustaceans and arachnids, as well as vertebrates such as turtles and tortoises. In turtles and tortoises, the underside is called the plastron.-Crustaceans:In crustaceans, the...
s, including lobes, turret
Turret
In architecture, a turret is a small tower that projects vertically from the wall of a building such as a medieval castle. Turrets were used to provide a projecting defensive position allowing covering fire to the adjacent wall in the days of military fortification...
s, grooves, pits and modified hairs. The function of these projections is little understood, but is presumed to be involved with courtship. In a few species the females have been observed to grip the males by the pits or grooves during copulation, using their cheliceres. They later ingested secretions produced by the male prosomic glands after depositing saliva-like fluid on them.
Distribution
More than 300 species occur in northern Europe, comprising about one fourth of the spider fauna there About 650 are known from North AmericaNorth America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
While they are the dominant spider group of the temperate and cold regions of the Northern Hemisphere they are less diverse in the Southern Hemisphere No native species have been found from New Zealand
New Zealand
New Zealand is an island country in the south-western Pacific Ocean comprising two main landmasses and numerous smaller islands. The country is situated some east of Australia across the Tasman Sea, and roughly south of the Pacific island nations of New Caledonia, Fiji, and Tonga...
and Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...