Black and Yellow Garden Spider – 9/24/10

Observer: April Forsman

Observation Date: 9/24/10

Observation Time: 10:15 a.m.

Observation Location: DPW

Common Name: Black and Yellow Garden Spider

Scientific Name: Argiope aurantia

Comments: Males range from 5 to 9 mm; females from 19 to 28 mm. Like other members of Argiope they are considered harmless to humans.The female of the species grows much larger than the male. Females have large rounded bodies that may grow to 40 mm (1 1/2 inches), excluding the legs. If the length of the legs is added, the female can reach 75 mm (3″) in diameter. Males are thin-bodied and only 20 mm (¾”) long. Garden Spiders often build webs in areas adjacent to open sunny fields where they stay concealed and protected from the wind. The spider can also be found along the eaves of houses and outbuildings or in any tall vegetation where they can securely stretch a web. The circular part of the female’s web may reach two feet in diameter. Webs are built at elevations from two to eight feet off the ground. Female Argiope aurantia spiders tend to be somewhat local, often staying in one place throughout much of their lifetime. After mating, the male dies, and is sometimes then eaten by the female. She lays her eggs at night on a sheet of silky material, then covers them with another layer of silk, then a protective brownish silk. She then uses her legs to form the sheet into a ball with an upturned neck. Egg sacs range from 5/8″ to 1″ in diameter. She often suspends the egg sac right on her web, near the center where she spends most of her time. Each spider produces from one to four sacs with perhaps over a thousand eggs inside each. She guards the eggs against predation as long as she is able. However, as the weather cools, she becomes more frail, and dies around the time of the first hard frost. (from Wikipedia)

More Information: Animal Diversity Web