April 20, 2013 in Washington Voices

Though creepy, most spiders can be helpful

Pat Munts
 
File photo

A tiny spider, colored like the surrounding tree bark, freezes as a photographer’s lens closes in for a photo last May in Riverfront Park.
(Full-size photo)

Spiders are a much maligned garden insect.

While some spiders can inflict a serious bite and scare us when they “drop” in, most spiders are good guys in the garden. They are very good at catching other bugs, larva and caterpillars that would otherwise be chomping on our plants. And they do it 24/7 without us having to pay them.

There are 37,000 known species of spiders worldwide with 3,000 of them found in North America. The Inland Northwest has its fair share of these.

The orb-weaving spider is the most familiar garden spider. We don’t often see the spider itself but we do see its beautiful wheel-shaped webs covered with morning dew backlit by the sun. Think of Charlotte the spider in “Charlotte’s Web.”

The sheetweb spider builds an irregular sheet of webbing around plants and other objects in the garden and beyond. The spider itself tends to drop quickly to the ground when disturbed.

Crab spiders resemble their namesake and are very colorful. They prefer plant blossoms where their coloring allows them to blend in and pounce on unsuspecting bugs.

Then there are the funnel-web builders. This large group of spiders builds their webs in dark, moist areas such as dark corners of gardens, sheds and wood piles. Their webs have two large openings that decrease in size toward the middle. The spider hides near one of the openings and waits for a victim to disturb the web before pouncing.

The only truly dangerous spider we have in the region is a single species of black widow, Latrodoctus hesperus, the Western black widow. Female Western black widows are about 1  1/2 inches in diameter and velvety black with the characteristic red hourglass on the underside of the abdomen. They are shy and prefer to live around undisturbed wood piles, old lumber, dry crawl spaces, outbuildings, rock piles or bales of hay away from a lot of human activity.

There is some debate as to whether the brown recluse spider is present in the region. Officially, the few recorded occurrences of the spider in the Northwest were the result of it hitchhiking in from the southern part of the United States on trucks and trailers. Most people mistake the common large house spider for a brown recluse.

Unfortunately, sometimes even a harmless spider can bite, if it feels threatened or trapped. Spiders prefer to run first. If their hiding place happens to be a piece of clothing, bed linens or the wood pile, it is easy for them to feel threatened when they get squeezed as you put on the clothes, get into bed or pick up an armload of wood. As a result they bite. In fact the most common spider bite is on the insides of the forearms where that armload of firewood meets bare flesh.

If you are bitten, clean the bite with water and soap and apply an antiseptic ointment and check with your doctor for further care.

So watch for spiders this spring and thank them for keeping the bad bugs in the garden under control – even if they startle us once in awhile.

Pat Munts has gardened in the Spokane Valley for more than 35 years. She can be reached at pat@inlandnwgardening.com.


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