Thursday, August 20, 2015

Golden Garden Spider

The Golden Garden Spider (Argiope aurantia) goes by a variety of common names.

     The Golden Garden Spider (Argiope aurantia) has numerous common names: Yellow Garden Spider, Golden Argiope, Black-and-yellow Garden Spider, Writing Spider, Zigzag Spider, Signature Spider, Common Garden Spider, Corn Spider, McKinley Spider, Yellow Garden Orbweaver, and Zipper Spider for examples. This large and colorful orb weaving spider is common in fields and sunny gardens where it constructs its large (up 2ft) web low to the ground where they are protected from the wind.
     The web typically has a reinforced web decoration called a stabilimentum in its center. This web feature gives the spider several of its common names. The purpose of the zigzag webbing has often been debated. When young it is believed to help hide the spider. When older, some believe the web helps to keep large predators such as birds from stumbling into it and destroying the web. Others have theorized and some experiments seem to show that it makes the web attractive to some potential prey. Its favored prey include katydids, grasshoppers, and bees, though there are reports that even small lizards can be caught.

The web decoration, called a stabilimentum, gives this spider several of its common names and its function has many theories behind it.

     The web center is usually consumed each day by the spider and a new center built, while the outside structure tends to remain the same. The orb webs are usually less than three feet off the ground, but can be two feet in diameter. The spider usually hangs head-down in the center of the web with its legs paired up and spread. When threatened, it may shake the web vigorously, sometimes blurring the spiders appearance or making it appear larger and more visible. They may also drop down or hide in the nearby foliage if danger threatens.

This is what this Argiope spider looks like from underneath. The head-down position and spread, paired legs is typical for them. 

     Females can be almost two inches long, while the males tend to be much smaller, rarely reaching even 1/4 of an inch in size. The males are also more slender of build and often live or hang out on the outskirts of the female's web. They sometimes even steal food from the females. He needs to be careful however as she may eat him, particularly after mating. Males often have draglines ready and drop off if the female gets too close.

A Golden Argiope egg sac

     Their papery egg sacs are marble-sized and tough, holding up to 1,000 eggs, and are often hidden in the web. If well fed, 3-4 can be produced in one season. The young do not emerge until the following spring (though they normally are born in the Fall), often ballooning with the wind to new nest sites. The females live less than a year, dying by the first frosts. The males usually die right after breeding. 
     While large and colorful, these are not dangerous spiders. Although capable of biting, they rarely do so. A bite is supposed to be no worse than a bee sting. Here's a short video featuring this large, colorful garden spider which become more evident in late summer and early Fall:

1 comment:

  1. Just found a large female in my yard today.