''Hyptiotes paradoxus'', also known as the triangle spider, is a

cribellate Cribellum literally means "little sieve", and in biology the term generally applies to anatomical structures in the form of tiny perforated plates. In certain groups of diatoms it refers to microscopically punctured regions of the frustule, or o ...

orbweaver in the family

Uloboridae Uloboridae is a family of non-venomous spiders, known as cribellate orb weavers or hackled 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 ...

Description

Body

Adult males have a body length of 3–4 mm (0.12–0.16 in), females 5–6 mm (0.20–0.24 in). The

carapace A carapace is a Dorsum (biology), dorsal (upper) 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 tor ...

is Broad. It ranges from ginger to dark brown, and has a dense covering of hairs. The abdomen is orange-brown to reddish-brown, with faint black horizontal bands which extend around the sides. It is raised towards the anterior, giving the spider a hunched look, and it may bear a pair of small tubercules on the anterior side. The male has a darker and more cylindrical abdomen than the female, and it lacks the raised anterior. They have short, stout legs, which are coloured as the carapace. Mature males have extremely large

pedipalps Pedipalps (commonly shortened to palps or palpi) are the second pair of appendages of chelicerates – a group of arthropods including spiders, scorpions, horseshoe crabs, and sea spiders. The pedipalps are lateral to the chelicerae ("jaws") and ...

, similar in size to the carapace.

Eye arrangement

They have eight eyes in two rows, with the posterior row distributed across the midline of the carapace, and the anterior row halfway between the posterior row and anterior edge. The anterior median eyes are close together, and distant from the anterior lateral eyes; the posterior medians are spaced apart, with the posterior laterals on tubules on the side of the carapace, around halfway back.

Distribution and habitat

The species is found in Europe, Turkey and the Caucasus. In Europe, it is found in Lithuania and Latvia. It is also found in Estonia (

Saaremaa Saaremaa is the largest island in Estonia, measuring . The main island of Saare County, it is located in the Baltic Sea, south of Hiiumaa island and west of Muhu island, and belongs to the West Estonian Archipelago. The capital of the island i ...

and mainland) and Finland (

Åland Åland ( fi, Ahvenanmaa: ; ; ) is an Federacy, autonomous and Demilitarized zone, demilitarised region of Finland since 1920 by a decision of the League of Nations. It is the smallest region of Finland by area and population, with a size of 1 ...

), and, scarcely, in

South England Southern England, or the South of England, also known as the South, is an area of England consisting of its southernmost part, with cultural, economic and political differences from the Midlands and the North. Officially, the area includes Gr ...

. They live primarily in shrubs and

evergreen In botany, an evergreen is a plant which has foliage that remains green and functional through more than one growing season. This also pertains to plants that retain their foliage only in warm climates, and contrasts with deciduous plants, which ...

trees, however they have also been found in deciduous trees.

Behaviour

Web

The web is triangular, and consists of four radial threads connected by cribellate silk. It is kept taught by the spider holding onto one corner. When an insect is caught, the spider repeatedly loosens and tightens the web until the prey is tangled.

Reproduction

Males reach sexual maturity in early autumn. Due to their small eyes, they must rely on the female's cribellate silk dragline, which the female coats in a pheromone, and courtship is mainly based on vibrations sent across the web.

References

Uloboridae Spiders of Europe Spiders of Western Asia Spiders of Central Asia Spiders described in 1834 {{Uloboridae-stub