Wednesday, August 31, 2011

A female Argiope aurantia in a potato field.
A male (under side) Argiope aurantial in a potato field.

Argiope aurantia, the garden spider or corn spider, is stirring up some concerns in the panhandle. We seem to have a bumper crop of these critters this year and some people are concerned about their safety with these 8-legged behemoths lurking around. They are pretty striking; the females are black and yellow with long, black legs, and a body about 1/2 inch wide and 1 and 1/2 inches long. If you have arachnophobia, I'm sure that these animals would send you into shock. However, don't panic, they are good critters to have. They are not poisonous to humans or pets, although a large number of them (and their webbing) can make scouting field crops a notably unpleasant experience. However, they are beneficial for (at least) a couple notable reasons: 1) One of their common names is "corn spider" and they can be a frequent occurrence in corn fields around this time of year. In Nebraska, we irrigate quite a few acres of cropland. Many of these acres use overhead irrigation systems. These systems are held up and moved across the land with tires. Tires leave tire tracks that can hold pools of water and these tracks can make great breeding habitats for Culex sp. mosquitoes -- the vectors of West Nile Virus. These mosquitoes can be quite common, particularly in western Nebraska. Although adult garden spiders probably prefer something bigger like grasshoppers, the smaller, immature spiders may help keep those pestiferous mosquitoes down. 2) A quick search on my favorite reference database reveals many, many papers concerning the protein, material properties, and potential application of this species' silk. So, although some of you may cry, "eeek" upon walking up on one of these critters, they may also be giving a lot of benefit to us in return.