Missing Sector Orb Weaver – Zygiella X-Notata

The missing sector orb weaver, Zygiella x-notata, is a common spider species found throughout Europe and the United States. The original distribution area of this orb weaver spider is in Europe. The spider is most commonly found throughout the United Kingdom an Western Europe. However, over the last decades, the population has spread throughout the world. In the United States it is a common sight along the coastal areas of the East Coast as well as the West Coast.

The common name of this spider comes from the fact that the spider spins an orb shaped web with one missing sector. Therefore, it’s web somewhat resembles a round pizza with a missing slide. Since the missing sector orb weaver can have a very similar appearance to the furrow orb weaver (Larinioides cornutus), the peculiar web shape can be a great help to identify this spider.

Missing Sector Orbweaver Description

The legs and cephalothorax (the “head” of the spider”) of Zygiella x-notata are usually light brown with darker brown colorations or bands around the legs and the eyes. The spider’s abdomen is mostly cream-colored or silvery-grey with dark brown, sometimes black, markings that somewhat resemble two wings or an oak leaf. The coloration and markings on the spider’s abdomen are easily confused with the furrow orb weaver (Larinioides cornutus).

Outside of their webs, missing sector orb weavers are often confused with members of the Steatoda genus, the false widow spiders, especially the triangulate cobweb spider (Steatoda triangulosa). Since Steatoda spiders can deliver a painful bite, the harmless orb weavers are often mistakenly killed.

Size

An adult female missing sector orb weaver reaches an average body length of 0.25 inches (6-7 mm). Adult male specimen are around 30% smaller than females and have a smaller abdomen but the same coloration and markings as the female spider.

Web

The web of the missing sector orb weaver is very characteristic and a great unique feature that helps identify the spider. As other orb weavers, it builds and orb shaped web between plants or buildings. However, one piece, or sector, of the web is missing. The finished web resembles the shape of a round pizza (orb-shaped web) with a missing slice.

Bite

As other orb weavers, Zygiella x-notata does not pose a threat to humans or pets. The spider uses it’s mild venom to paralyze small flying insects that are caught in the web. Orb weavers are non-aggressive spiders and are great to have around the house, as they will rid the garden of mosquitoes and other pests.

Other Common Names

Next to its most used common name, the missing sector orb weaver, Zygiella x-notata is also referred to as the winter spider and the silver-sided sector spider.

Zygiella x-notata scientific classification

• Kingdom: Animalia
• Phylum: Arthropoda
• Subphylum: Chelicerata
• Class: Arachnida
• Order: Araneae
• Infraorder: Araneomorphae
• Family: Araneidae
• Genus: Zygiella
• Species: Zygiella x-notata

Distribution of the missing sector orb weaver

Next to their original geographic range in the United Kingdom and Western Europe, populations of the missing sector orb weaver can be found throughout the world. Larger populations have established in Japan, the Korean Peninsula, China, Indonesia, Northern India, North Africa, Eastern Europe and Turkey, Brazil and Argentina in South America as well as in the United States and in Canada.

In the United States, Zygiella x-notata can be found along the East and the West Coast, including Alaska. Namely, the spider occurs in the following states: Alaska, Washington, Oregon, California, Florida, Georgia, South Carolina, North Carolina, Virginia, Delaware, Maryland, New Jersey, New York, Connecticut.

References

• Taxon details: World Spider Catalogue
• Binominal name from: Clerck, 1757
• http://britishspiders.org.uk/wiki2015/images/2/26/Missing_sector_spreads.pdf
• Levi, Herbert Walter: “The orb-weaver genus Zygiella (Araneae, Araneidae).” in Bulletin of the Museum of Comparative Zoology, vol. 146, no. 5, p. 267-290, Cambridge 1974. ISSN 0027-4100
• Weissmann, Monika: Web-building and prey-capture in two orb-weavers. 1987.
• Venner, Samuel; Pasquet, Alain; Leborgne, Raymond (1 March 2000). “Web-building behaviour in the orb-weaving spider Zygiella x-notata: influence of experience”