The Homeowners Column

The Homeowners Column

Spiders are good guys

Photo of Sandra Mason

Sandra Mason
Extension Educator, Horticulture
slmason@illinois.edu

Halloween is the only time decorating with spiders and spider webs is considered cool. Otherwise spiders need a good spin-doctor. The movie arachnophobia certainly did not help their image. A tiny spider in the sink can compel the most self-assured person to scream for the designated spider killer in the family. Despite their reputation, spiders are beneficial. They eat all kinds of pesky bugs like flies and crickets. Actually they are opportunistic feeders and eat pretty much anything they can catch. I can relate to that lifestyle.

Most spiders are shy and will avoid humans. Spiders can bite if provoked but generally the venom is not particularly toxic and merely causes a reddened area of the skin. People can have an allergic reaction to a bite and would want to consult a physician especially if the bite is slow to heal. The dangerous spider bites from brown recluses and black widows are uncommon since the development of indoor plumbing. Spiders just loved those outhouses. Pictures of these reclusive spiders are readily available.

Once fall approaches, many spiders reach adulthood, mate, and lay eggs for next summer. Some of these spiders can get large and may cause unwarranted alarm.

Orb weavers are the most obvious large spiders since they spin large webs a foot or more in diameter during the night across sidewalks, doorways, between garden plants and in other areas where they are quite noticeable. That's why the first person down the hiking trail in the morning is the spider web collector. Most of the large, common orb weavers (Araneus) grow to a leg-span of 1-2 inches and have light and dark banded legs.

Another common orb weaver is the large yellow and black garden spider or argiope. It builds a 2-foot diameter web with a zigzag vertical strip of white silk in the center. They respond to vibration in the web by quickly running over to the prey, and subduing it by rolling it into a straightjacket of silk. It's great fun to catch a fly and toss it into a garden spider's web. It's not much fun for the fly, but cheap entertainment for the family.

Wolf spiders also may have a 2-inch leg span, but do not build an orb web in which to catch their prey. Like their namesake, they run down and overpower the crickets, earwigs, and other insect prey. Many of the wolf spiders are hairy, dark brown and have a stripe or pattern down their backs. After hatching, the young spiderlings will ride on their mother's back for a few days before venturing off on their own. Wolf spiders are nocturnal and live among fallen leaves in taller grass, ground covers, and in other protected areas. They may wander into homes through cracks and crevices in the foundation as the temperature drops in the fall.

Widespread destruction of spiders should be avoided and is not necessary. To keep spiders out of your home, clean up woodpiles and leaves from around the foundation. Caulk cracks and crevices around the foundation, windows and doors. Use a hose with high-pressure water to remove spiders from outside walls. Use yellow or sodium vapor lights outside to reduce night flying insects around the home. Spraying the outside foundation and the soil next to it with pyrethrum insecticides such as permethrin may keep unwanted invaders out. Be sure to read and follow all label directions.

Once in the home most spiders can be scooped up and gently deposited outdoors by the designated spider remover. Or can be removed by vacuuming. Also move and dust often behind and under furniture, stored materials, wall hangings and ceiling corners to discourage spider establishment.

Next time you see a spider just repeat this sentence, spiders are good guys. Spiders are good guys.

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