spotted orbweaver

not listed

NNR - Unranked

not listed

There are 123 spotted orbweaver species (genus Neoscona) worldwide. They are among the most common and abundant orb weaver spiders worldwide, and are among the most common of all spiders in North America. Only 8 species occur in North America north of Mexico.

Spotted orbweaver is a medium-sized orbweaver. It occurs in the United States from Maine to Minnesota south to Florida and Arizona, in southern Ontario Canada, and in Mexico. It is common in southeastern Minnesota, where it is at the northwestern extent of its range, but is mostly absent in the remainder of the state. It is found in open woodlands on shrubs and tall forbs, and on fences and buildings. It is seldom found on grasses.

North American spotted orbweavers are readily identified by the pattern of markings on the upper side of the abdomen. On spotted orbweaver the lack of conspicuous markings is an identifying feature. The female can be 5⁄16″ to ¾″ (8.5 to 19.7 mm) in length with a ¾″ to 15⁄16″(20.4 to 24.4 mm) legspan, but is usually just ⅜″ to ½″ (10 to 12 mm) long. The male is slightly smaller, ⅛″ to ⅝″ (4.5 to 15 mm) in length.

The front part of the body (cephalothorax) is much smaller than the abdomen. The upper side (carapace) is reddish-brown to brown and has a longitudinal furrow in the middle. On males the sides of the carapace are nearly black.

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, and the posterior median eyes (PME) are slightly smaller than the anterior median eyes (AME). On each side the lateral eyes are widely separated from the middle (median) eyes and are almost touching each other. The median ocular area (MOA), the area defined by the middle four eyes, is longer than wide and narrower in front than behind.

The abdomen is large, triangular-oval, and broadest toward the rear. On the female it becomes oval when swollen with eggs. There are no low rounded humps (tubercles) in the shoulder (humeral) area. The color on the upper side is variable. It may be brown, reddish-brown, yellowish-brown, or orangish-brown. On the female it is sometimes white. Markings on the abdomen are obscure or entirely lacking. On the underside of the abdomen there is a large black spot bordered on each side by a white, more or less straight line or elongated white spot, and on the bottom by two yellow lines. Together, the spots can be described as two “broken Ls”.

The legs are spiny and mostly yellow with brown bands. The first pair of legs is the longest, the third pair is the shortest. The bands on the third and fourth pairs of legs are conspicuous and very dark. The third segment (femur) on all legs is brown. On the male, the first segment (coxa) on the front pair of legs has a spur on the underside; and the fifth segment (tibia) of the second pair of legs has two rows of straight, clasping spines on the outer lateral surface that run the entire length of the tibia.

Female Body Length: 5⁄16″ to ¾″ (8.5 to 19.7 mm)

Male Body Length: ⅛″ to ⅝″ (4.5 to 15 mm)

Legspan: ¾″ to 15⁄16″(20.4 to 24.4 mm)

The web hangs vertically and can be 16″ to 24″ (40 to 60 cm) in diameter. It is called an “orb”, which gives this family of spiders its common name. The orb has 18 to 20 radii 30 or more sticky spirals. A retreat is constructed near the top of the web consisting of a leaf folded over and secured with silk threads.

Barn spider (Araneus cavaticus) has a raised tubercle on each side of the abdomen in the shoulder (humeral) area. The black spot on the underside of the abdomen is bordered on each side by a white, unbroken, comma-shaped spot.

Open woodlands, fences, and buildings

June to November

Spotted orbweaver builds a new web every evening around dusk. It sits motionless in the center of the web, head down, waiting for prey to be snared. In the morning shortly after dawn it recycles the web by eating it. The spider usually spends the daylight hours in the retreat. Occasionally the female will leave the web up during daylight hours, probably due to the need to feed the developing eggs.

Moths, crane flies, and other insects.

Sources

7, 24, 29, 30, 82.

Berman, J. D. & Levi, H. W. (1971). The orb weaver genus Neoscona in North America (Araneae: Araneidae). Bulletin of the Museum of Comparative Zoology 141: 465-500.

Common and abundant

large orb weaver!

Part of the web appeared to be anchored to the power lines 15 feet above it.

Appears to be a female, building her web on the High Bridge

Ventral view

Dorsal View

Ventral View

Location: Houston, MN

large orb weaver!

Location: Eagles Bluff Park, La Crescent

Location: Albany, NY

Location: St. Paul

Part of the web appeared to be anchored to the power lines 15 feet above it.

Location: Woodbury, MN

Location: St. Paul, Ramsey County, MN

Appears to be a female, building her web on the High Bridge

Location: Sibley House, City of Mendota, Dakota County

Ventral view