tuftlegged orbweaver

not listed

NNR - Unranked

not listed

Tuftlegged orbweaver is a small typical orbweaver. It occurs in the United States and southern Canada east of the Great Plains and in northeastern Mexico. It is common in Minnesota. It is found in bushes and trees in forested areas and in low shrubs and tall grasses in grassy areas.

The female is ⅛″ to 3 ⁄16″ (2.3 to 4.5 mm) in length with a 3⁄16″ to ⅜″ (5 to 10 mm) legspan. The male is much smaller, 1⁄16″to ⅛″ long.

The front part of the body (cephalothorax) and the legs are yellowish or brownish-yellow. The upper side (carapace) is much smaller than the abdomen, more or less rounded at the rear when viewed from above, and moderately convex when viewed from the side. There is a longitudinal furrow in the middle. A narrow black stripe extends from just behind the eyes into the furrow and to the base of the carapace. There are no horny outgrowths. There is a dark stripe on the lateral margins, at least near the base.

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 PME have black eye rings. 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 and elliptical or oval and narrowest in front. There are no low rounded humps (tubercles) in the shoulder (humeral) area. The upper surface is white with a broad dark stripe in the middle, a narrow light stripe on each side, and three light oblique lines on each side. The width and color of the stripes is highly variable. The middle stripe is narrow in front and broad behind. It may be light brown with a dark margin or entirely medium brown. It encloses two white spots and two rows of three black spots. The pale stripes and lines may be yellow, brownish-yellow, or brown. The underside is mostly dark with white spots. On the male the carapace is darker and the middle stripe on the abdomen is much darker.

The legs are highly variable in color but usual pale near the base with dark areas at the end of each segment. They are armed with long black spine-like hairs. There is a row of spines on the underside of the third segment (femur) of the second two pairs of legs but not on the first two pairs. On the fifth segment (tibia) of the third pair of legs there are two oblique rows of 5 or 6 long slender hairs on the underside near the base. This is the feature that gives the spider the first part of its common name, however it is shared with all spiders in the genus Mangora.

Female Body Length: ⅛″ to 3 ⁄16″ (2.3 to 4.5 mm)

Male Body Length: 1⁄16″to ⅛″ (2.0 to 2.8 mm)

Legspan: 3⁄16″ to ⅜″ (5 to 10 mm)

A tightly woven hunting web is constructed in tall grass or on a low shrub, bush, or tree. It is called an “orb”, which gives this family of spiders its common name. The orb may be vertical or inclined. It is about 12″ in diameter, very large for such a small spider. It has 30 to 70 radii and numerous, usually very closely spaced, sticky (viscid) spirals.

Lined orbweaver (Mangora gibberosa) has two black lines or rows of black spots on the back half of the abdomen. The cephalothorax appears swollen on each side of the furrow, and the dark line in the middle extends into the thoracic groove but not to the base. There is a thin black line on the underside of the femur of the first and second pairs of legs. The web has a bullseye-like decoration in the center.

Forests and grassy areas

Early May to August

In early fall the female creates a sac for her eggs in a small leaf folded and reinforced by strands of silk. The eggs hatch in the fall and the spiderlings overwinter in the egg sac.

Sources

24, 29, 30, 82.

Common

Location: Albany, NY

Location: Woodbury, MN