(Photos from Aggie Horticulture, Galveston County http://aggie-horticulture.tamu.edu/galveston )
Ag Biz News Column
County Extension Agent –Ag/NR
Spiders around the Home
Ask people what they are afraid of and in many cases spiders rank in the top of the list. Most spiders, however, are considered beneficial and cause no harm to humans. Spiders help keep flies and plant feeding insects under control.
Spiders are arachnids and are more closely related to mites and scorpions than to insects. Most spiders have eight simple eyes though some species have six, four, two or even no eyes at all. The pattern and number of eyes is useful to help identify what spider you may have. Female spiders are usually larger than male spiders as well.
Only two types of spiders in Texas are considered medically significant and they are the Brown Recluse and the Widow Spiders. Learning how to identify spiders is important as most spider species are considered beneficial.
If you want to keep spiders from entering your home, install and repair weather stripping around doors and windows. Seal and caulk around lighted doors and windows. It may be necessary to relocate fire wood piles. Prune shrubbery or trees that touch the house. Seal cardboard or other storage containers with tape or other means to keep spiders out.
Common spiders include orb weavers, crab spiders, wolf spiders, and jumping spiders. Orbweavers spiders include the black and yellow garden spider (Argiope aurantia). The black and yellow garden spiders are large orbweaver spiders. These spiders weave a zipperlike seam of heavy silk into the web that is called a stabilimenta. Spinybacked orbweavers are common in wooded areas. These orbweaver spiders have a flattened, spiny shape that makes them resemble a crab. The spiny orbweaver’s abdomen can come in a number of colors including white, yellow, orange, and red.
Crab spiders are common on leaves and flowers. These spiders are easily recognized by the crablike way they hold their front pairs of legs and the way they scuttle sideways and backwards. Crab spiders do not spin webs but they ambush their insect prey instead. Some crab spiders can even change color to match the flower they are perched upon.
Wolf spiders are among the most common spiders in backyards and fields. These spiders are hairy and their color patterns include mottled brown, gray, black, yellow, and creamy white. Wolf spiders are more active after dark and have good night vision. Wolf spiders are often confused with brown recluse spiders. Wolf spiders may have dark stripes but lack the fiddle-shaped marking on their cephalothorax that recluse spiders possess. Wolf spiders have eight eyes while recluse spiders have six eyes arranged in a pair.
Jumping spiders are a stocky, brightly colored spider species. Common color patterns include browns, grays, black, red, yellow, metallic or iridescent greens, blues, and coppers. Jumping spiders have excellent vision and use this to help catch prey. Jumping spiders are territorial and hunt during the day. Jumping spiders actually jump and this can sometime startle some that come in contact with these spiders.
Spiders attack flying insects that get trapped in its web. Spider webs capture aphids, flies, grasshoppers, mosquitoes, and wasps to name a few insects they help control. In some instances, the spider webs become a nuisance when they are built in places inconvenient to humans. Spider webs are a marvel of architecture. Many spiders tear down and rebuild their webs daily. Spiders are all around us and proper identification can be a useful tool around the home.
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