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United States Department of Agriculture

Agricultural Research Service

spiderfright




Sound familiar? Lots of people are 'fraidy cats when it comes to spiders. It's true that spiders are predators--animals that chase, capture and kill other animals for food. But spiders often get unfair treatment.


Very few of these eight-legged predators would bite you, even if they wanted to. Even tarantulas are pretty harmless; some people have them as pets. (But don't go picking one up unless an adult says OK!)


Other bugs, like pesky flies, have plenty to fear from spiders, though. Lots of them end up as spider snacks, although spiders don't chew their food. Instead, a spider sips, sucking out an insect's gooey insides and skipping the crunchy outer part.

"Am I bugging you yet?"


Orbweaver spider waiting for a snack.Disgusting, maybe... But spiders might be miniature heroes, like the long-jawed orbweaver, in the picture left. Scientists at the Agricultural Research Service believe some spiders might help control insect pests that destroy our crops.

Hurray for the spiders!

For many years scientists have studied insects and microorganisms, such as bacteria, for their ability to kill crop pests.

Recently they have turned to spiders. They start by collecting lots of spiders and finding out what they like to eat. When a scientist finds a spider that likes to turn bad-guy bugs into a liquid lunch, that spider will get the scientist's undivided attention--in research studies.


Spiders aren't insects, although they have similarities. Can you think of some? And can you tell which of these animal groups spiders REALLY belong to?


1. Aardvark?

2. Arachnid?

3. Archaeopteryx?


Research assistant Brian Jones puts the spider vacuum to good use.How do scientists trap spiders in farm fields without hurting them? In Oklahoma, ARS entomologist Matthew Greenstone, his assistant Brian Jones, at right, and other researchers have used giant--but gentle--vacuum cleaners. Then the scientists figure out what little critters a spider has been eating.

One way to do this might be to dissect the spider (cut it open), but they'd see only a gooey mess! So, Greenstone, pictured below, and others created a special chemical test. It can identify a prey's remains in a predator's gut. You might call this a "gut reaction."

Mathew Greenstone hard at work in the lab. Spread in trays before him are the chemical contents of digested insects eaten by captured and dissected spiders. Yumm. In a Georgia cotton field, scientists using the test found that one type of spider really likes to eat the eggs of two insects that attack the cotton plants.

Recently, they surveyed wheat and other grain crops in Colorado, looking for spiders that kill aphids, which are major pests of these crops.

When scientists find a spider species with an appetite for a particular pest, they can investigate whether these spiders might eat enough pests to help a farmer. Scientists also want to find ways that farmers can make their fields more inviting to the spiders.


The real "Web Master"Most spiders catch insects by spinning webs of strong, sticky silk. How else do spiders capture their prey?


A. Spring from under trap doors.

B. Spin lassos to rope them.

C. Hide and surprise their prey.

Yikes! Time to go!

Come here you!I'm out of here!So, unless you're an insect yourself, spiders are usually nothing at all to fear. Next time you see a spider crawling around your garden, let it be and wish it well. It just might be standing guard over your flowers and vegetables!


--Bob Sowers, Information Staff, Agricultural Research Service.


To learn more, check out the full story, written by Hank Becker, in Agricultural Research magazine at: http://www.ars.usda.gov/is/AR/archive/aug98/spid0898.htm


Credit for spider, fly, caterpillar and spider web graphics goes to Lisa Konrad, at the Animation Arthouse


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Last Modified: 2/14/2011
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