cross orbweaver

not listed

not listed

not listed

Cross orbweaver is an exotic, large, sedentary spider. It is native to Europe where it is extremely common. It was introduced into northeastern North America more than 140 years ago. The oldest North American record is from Newfoundland in 1881. In the United States it now occurs in the east from Maine to New Jersey, west to Minnesota and Illinois, and west of the Rocky Mountains from northern Washington to southern California. It occurs in southeastern Minnesota, where it reaches the western extent of its eastern range. Adults are found in late summer and fall in urban areas around buildings, in parks, and in gardens. They are often found in shrubs between houses.

Females are ¼″ to ¾″ (6.5 to 20 mm) in length and have a ¾″ to 1½″ (20 to 40 mm) legspan. The overall color is variable, pale light yellowish-brown, brownish-orange, grayish-brown, or very dark brown. The following description is of the yellowish-brown color phase.

The front part of the body (cephalothorax) is low, narrowed in front, and much smaller than the abdomen. The upper side (carapace) is uniformly yellowish-brown and is covered with shiny hairs. There is a brown or dark brown longitudinal stripe in the middle, and a dark irregular stripe near each lateral margin. The underside is dark brown.

There are eight eyes arranged in two parallel rows of four eyes each. The rear row is curved forward, the front row is straight or slightly curved backward. All of the eyes are small, but the median eyes are larger than the lateral eyes.

The abdomen is large, oval, rounded, and highest in front. There are two low rounded humps in the shoulder (humeral) area. The upper side is yellowish-brown and hairy. There is a pale, cross-shaped pattern of white spots toward the front. This is the feature that gives the spider its common name. Toward the rear there is a leaf-shaped mark (folium) with four pairs of large dark marks and several small white spots. On the underside of the abdomen there is a black longitudinal stripe in the middle and a pair of white spots near the rear.

The legs are long, very spiny, and yellowish-brown, with distinct dark brown rings. The front two pairs project forward, the hind two pairs project backward. The last segment (tarsus) on each leg has three claws at the tip, though these are not visible to the naked eye.

The male is smaller, ¼″ to ½″ (5.7 to 13 mm) in length. There are no humps on the abdomen and the folium is more distinct. The legs are darker and the banding is less distinct. The fifth leg segment (tibia) is stout and curved, and it has two rows of short, stout hairs (setae).

Female Body Length: ¼″ to ¾″ (6.5 to 20 mm)

Male Body Length: ¼″ to ½″ (5.7 to 13 mm)

Legspan: ¾″ to 1½″ (20 to 40 mm)

The web is large and oval. It is called an “orb”, which gives this family of spiders its common name. It is about 12″ (30 cm) in diameter and hangs slightly inclined from the vertical. There are usually about 30 radii. The center of the hub is closed. A retreat is sometimes constructed near the web in a rolled up leaf when available, otherwise it is made entirely of silk.

Urban areas around buildings, in parks, and in gardens

Late summer and fall

The male matures earlier than the female. It chooses an immature female and stays close to her until she matures and they can mate.

In Minnesota, eggs probably overwinter. In warmer climates, juveniles overwinter in bark crevices or in dead leaves.

Sources

24, 29, 30, 82, 83.

On web, St. Louis Park, Hennepin County, Minnesota.Photo taken August 3, 2022.

Dorsal view on web, Garage at Barnes Prairie, Racine County, Wisconsin. Photo taken August 4, 2021.

Ventral view on web, Garage at Barnes Prairie, Racine County, Wisconsin. Photo taken August 4, 2021.

Location: St. Louis Park, Hennepin County, Minnesota

On web, St. Louis Park, Hennepin County, Minnesota.Photo taken August 3, 2022.

Location: Barnes Prairie, Racine County, Wisconsin

Dorsal view on web, Garage at Barnes Prairie, Racine County, Wisconsin. Photo taken August 4, 2021.