JULY
1993

 

 

 

By
Tom Turpin
 
Professor of
Entomology
Purdue University

 

 

 

 

 

7-08-93

Spiders Sport Silk Spinners

Spiders are not insects, but insects and spiders are arthropods since both have jointed legs. Spiders have eight, not six, legs and most produce silk.

The name “spider” comes from the Anglo-Saxon word “spinnan,” meaning to spin. The silk is produced in liquid form by organs called spinnerets. One of the strongest natural fibers known, silk hardens immediately as it is pulled from the spinnerets. It can stretch as much as one-fourth of its length before breaking.

Web production is the most common use of silk by spiders. The webs then are used to capture insects — spiders’ favorite food. Webs of various spiders are distinctive and can be used to identify the species.

Most spiders use silk to make egg sacs. These egg sacs frequently are found suspended in corners of basements and garages.

Other uses for silk include producing a nursery for the young, lining tunnels, and wrapping prey that is captured.
Spiders also use silk as a method of flying. During this process, called ballooning, the spider releases strands of silk. When the strands get long enough, the wind carries the spider from one place to another. These masses of ballooning silk strands, known as gossamer, are especially noticeable in the fall when spiders have had all summer to do their weaving.

Spider draglines are made with silk. These draglines are used by spiders to make the foundations of a web and as safety lines, much as those used by construction workers. These draglines also are used by spiders to retrace their steps — all eight of them.

It probably was one of these draglines that was used by the spider that frightened Little Miss Muffet. This immortalized spider has been shown crawling on a silken thread from the ceiling near Miss Muffet’s tuffet. When the supping Miss Muffet spied the spider, she skedaddled. This is a common human reaction when encountering a spider — an overreaction in most instances, because most spiders are harmless to humans.

Spiders should, in fact, be considered friends of homeowners. They feed on all those insects that we don’t like.

 

Writer: Tom Turpin
Editor: Andrea McCann