| Cribellate orb-weavers | |
|---|---|
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| Uloborus plumipes | |
Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Chelicerata |
| Class: | Arachnida |
| Order: | Araneae |
| Infraorder: | Araneomorphae |
| Family: | Uloboridae Thorell, 1869 |
| Diversity | |
| 19 genera,337 species | |
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Uloboridae is afamily of non-venomousspiders, known ascribellate orb weavers orhackled orb weavers. Their lack of venom glands is a secondarily evolved trait. Instead, they wrap their prey thoroughly in silk, cover it in regurgitated digestive enzymes, and then ingest the liquified body.[1]
They are medium to large spiders, with three claws, which lack venomous glands. They build a spiral web usingcribellate silk, which is quite fuzzy. They are usually dull in color, and are able to camouflage well into their surroundings. They typically have a humpedopisthosoma, which is notoriously more humped than thecarapace. Their rear eyes tend to curve, more so in some species than others.[2] Most uloborid spiders have eight eyes, but the genusMiagrammopes has only four.[3]
The hunting method of thesespiders is quite unique among allanimals in the kingdom. These spiders do not use an adhesive on their orbwebs, but rather the very finecribellate fibers on each strand ofsilk tend to ensnare prey.[4] Since newly hatched uloborids lack the cribellum needed to produce cribellate sticky silk, their webs have a fundamentally different structure with a large number of fine radii, but no sticky spiral.[5] Some spiders only build a single line web, while others make more complex webs. They lackvenom glands, which is very rare among spiders. They first catch their prey, using their silk. They wrap their prey, and severely compress it, then they cover the prey withdigestive fluid. Oddly enough, their mouthparts never touch the prey. The spider starts ingesting as soon as the prey has been covered. It is thought that robust hairs protect the spider from the digestive fluids.[6] It is unknown how this behavior first evolved.
Some species are able to form colonies[2] likePhiloponella republicana, which make large, messy, communal webs. Colonies may range from a couple of individuals to a couple hundred. These colonies may benymph dominated or adult dominated, though a small colony dominated by adults could be a sign of the colony's slow death. These colonies show signs of being female dominated, as one would expect, with males only being found in larger colonies. This could mean males search for larger colonies, or had died out in the smaller colonies.[7]
This family has an almost worldwide distribution. Only two species are known from Northern Europe:Uloborus walckenaerius andHyptiotes paradoxus. The oldest known fossil species isTalbragaraneus from theLate Jurassic (Tithonian)Talbragar Fossil Bed of Australia.[8]
As of May 2024[update], theWorld Spider Catalog accepts the following genera:[9]
Data related toUloboridae at Wikispecies
Media related toUloboridae at Wikimedia CommonsAuthority control databases: National |
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