Scientific Name
Micrathena sagittata
Common Name
Arrowshaped Micrathena
Other Names
Arrowshaped Orbweaver, Arrow Spider
Explanation of Names
- Author: Charles Athanase Walckenaer. First year published: 1841, as Plectana sagittata.
- Pronunciation: My-kruh-THEE-nuh saa-juht-TAY-tuh
- Meaning: Micrathena is after the Greek adjective “small” and the name of the goddess Athena (who wore armor and was also a weaver, among other things); sagittata is Latin for “arrowed.”
Appearance
- Size: Body length of mature female 8-9 mm; male 4-5 mm.
- Color: Carapace of the female is dark reddish brown edged in pale yellow or ivory; abdomen is mostly bright yellow above, but the “spikes” are reddish brown (black at the tips). The underside is mottled black and yellow. Legs are deep reddish brown. The male is mostly black with scattered white markings on the abdomen.
- Eyes: Eye arrangement typical of orb weavers (family Araneidae). Total of eight eyes.
- Legs: Legs are proportionate to body size. They are rather shiny and without any spines visible to the naked eye.
- Body: This spider is named for the arrow-shaped abdomen of mature females which is widest at the rear, with a pair of very large processes (“spikes”) jutting obliquely from the hindmost part of the abdomen. Two additional smaller sets of “spikes” are on the front and middle of the abdomen. The abdomen of the male is widest at the rear, but lacking spines.
Range
Found in the eastern United States west to Nebraska and Texas, and more common in the southern part of its range, which does extend to Panama.
Habitat
This is a spider of mostly open deciduous woodlands and forest edges. Can be found among shrubs and other foliage.
Web
Orb web is usually built in low bushes, rarely more than two feet from the ground. It is typically about one foot in diameter. The web has a very “tight” appearance with many radii (“spokes”), and the spiral very tightly wound and closely spaced. A decoration of a short, zigzag band of silk called a stabilimentum, may be positioned just above the center of the web. Spider occupies hub (center) of web, hanging head down. The web may be vertical or slightly inclined. The spider will drop from the web into leaf litter if disturbed.
Season
Mature individuals may be found from mid-summer through late autumn, perishing with the first hard frost.
Food
Prey is flying and jumping insects that are intercepted by the vertical web. At least one researcher (Fitch, 1963) claims the principal prey are leafhoppers (insects in the family Cicadellidae), though more diverse prey is recorded in non-agricultural habitats (Uetz and Biere, 1980).
Life Cycle
Egg sac is fluffy, spherical, about 12 mm in diameter, and containing roughly 90 eggs.
