six-spotted orbweaver

not listed

NNR - Unranked

not listed

Six-spotted orbweaver is a small cucumber spider. It occurs throughout Europe and North America and in parts of Asia. It is the only Araniella species in the United States, where it occurs in the east and the west but is mostly absent from the Great Plains and from the Gulf States. It is common in Minnesota. It is found on trees and shrubs and sometimes on fences.

Females are 3⁄16″ to ¼″ (4.8 to 7.2 mm) in length and have a ⅜″ to ⅝″ (10 to 17 mm) legspan. Males are smaller, ⅛″ to 3⁄16″ (4.0 to 5.0 mm) in length. The color is highly variable but the spider is easily identified by its markings.

The front part of the body (cephalothorax) is large but smaller than the abdomen. The upper side (carapace) is smooth and almost hairless. It may be yellowish, brownish-yellow, or brown. There are no markings and there is no longitudinal depression in the middle. The head is low and wide.

There are eight eyes arranged in two parallel rows of four eyes each. The eyes are on black spots but are not on raised projections (tubercles). The rear row is slightly 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 oval, widest in the middle. There are no humps in the shoulder area (humeral tubercles). The upper side is usually off-white or yellowish but may be also greenish, reddish, pinkish, or brownish, and often has areas of two or more of these colors. There are three pairs of small black spots ringed with white on the rear half near the sides. This is the feature that gives the spider the first part of its common name. There are often three pairs of tiny blackish spots in the middle. The leaf-shaped marking (folium) is usually absent, sometimes represented by irregular white lines.

The legs are short, stout, spiny, and the same color as the carapace but often lighter. They are not banded but are darker toward the end. The first pair of legs is the longest, the third pair is the shortest.

On the male the legs and carapace are darker. The spots on the abdomen are larger and more distinctly surrounded with white, which sometimes coalesces into a white stripe on each side. The legs are longer. The first segment (coxa) on the front pair of legs has a hook-like spur on the underside. This spur fits into a groove on the upper side of the third segment (femur) on the second pair of legs. The second segment (tibia) on the second pair of legs is neither curved nor thickened. The femur of each leg has a row of spines on the underside.

On juveniles the carapace, legs, and sometimes the abdomen, are often red.

Female Body Length: 3⁄16″ to ¼″ (4.8 to 7.2 mm)

Male Body Length: ⅛″ to 3⁄16″ (4.0 to 5.0 mm)

Legspan: ⅜″ to ⅝″ (10 to 17 mm)

The web is very small and is often enclosed by bending over a single large leaf. There is no retreat.

One generation per year: May to fall.

The spider is active during the day. It sits in the center of its web and waits for prey.

Spiderlings in the final development stage (instar) overwinter.

Sources

24, 29, 30, 82.

Common

Location: Woodbury, MN