Wednesday, September 14, 2011

Wildlife of the James - Golden Garden Spider

Not an Itsy-Bitsy Spider! Meet the Golden Garden Spider

by Jessica Templeton, JRA Ecology School Manager

One of the local spiders whose appearance just might stop you in your tracks is the Golden Garden Spider, or the Black-and-yellow Argiope (Argiope aurantia). The large, black spider with conspicuous yellow coloration on its abdomen can be spotted around the James River from your backyard garden to shrubby brush around the river banks.

You can spot the spider adorning its spiraling web during the daytime. It is usually positioned in the center of the web, facing downward towards the ground. The web is almost more eye catching then the brightly-colored spider with thick white zigzag patterns that vertically span the height of the spider’s orb.

There is much debate in the scientific world about why the Argiope would spend the extra energy and resources necessary to build these seemingly extraneous patterns, named stabilimenta. Originally thought to provide extra stability to the web, from which they originally received their name, this theory has since been dismissed. One study from Ohio State University suggests that the stabilimenta serve a defensive purpose, making their webs more visible to birds who may otherwise fly through and damage their creation (Oxford Journals). Recent studies also suggest that the zigzag patterns in the web may help reflect ultraviolet light acting as an effective predation tool to attract insects to their web (American Wetland Resources) While the intent is still unclear, Argiope do not always build stabilimenta into their web, suggesting that there is significant cost associated with the design that the benefits need to outweigh.

Even though the Garden Spider can be intimidating by appearance, it is a harmless bit of wildlife on the James. If startled, they will vibrate their web to make themselves appear more intimidating (Desert USA). If this doesn’t work, the spider will quickly drop off of its web and onto the ground in pursuit of a good hiding spot. Next time you spot a Garden Spider, put your mind at ease and take a moment to consider what purpose you think its distinctly patterned web may serve.

1 comment:

  1. We have two huge GG spiders outside of our garge now and they are so cool and the kids love watching them! We fed one of them another spider and it was neat to watch our GG feed on it!

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