Insects – what comes to mind when thinking of them? Of course there are undesirables such as mosquitoes and ticks. There are the important beneficials such as pollinators, think bees, without which we would not have many food crops. Then there are perhaps some lesser-known beneficial insects that have contributed to our lives for centuries. Some of the greatest achievements of man have been built on the bodies of insects. They are our valuable partners, but one could say they get the raw end of the deal.

One may be quite familiar with their "end product contributions" but less so with their actual role in creating these end products. Being an avid quilter I use silk thread to sew appliqué (pieces of fabric) onto a quilt top. I have always been fascinated by how silk thread and silk fabric come from a worm! I use silk because it is quite strong and smaller in diameter which helps hide stitching. Because of how it is produced, it is more expensive than cotton thread.

Native to Asia, silk was discovered around 3,500 BC in China. Silk is a lustrous natural fiber that comes from the cocoons of silkworms, larvae of the mulberry silk moth Bombyx mori. The female moth lays 300-500 tiny eggs and after around 10 days, the larvae (silkworms) emerge to feed on mulberry leaves. After some 30 days, the worms, more correctly called caterpillars, spin a cocoon slightly over an inch in height and one-half inch diameter. The accompanying photo is a cocoon I purchased from a silk thread vendor at a quilt show. One can see the silk fibers wrapping all around it. Cocoons are collected, boiled to kill the larvae, and essentially unwound by a single strand to be rewound into silk thread. The various caterpillar species raised today are distinguished by the quality of the silk they produce. It can take up to 2000 cocoons to produce a silk dress. No engineer has been able to replicate the special luster of silk.

In 1920, brothers J. H. and C. K. Eagle built and operated several silk mills. Although their main office was in New York City, their manufacturing operations were in Shamokin, Mechanicsburg, Bellefonte, Phoenixville and Gettysburg. The Gettysburg throwing mill opened in 1921 and was located close to the railroad. An illustration from the PA Historic Resources Series Eagle Silk Mill (2006) shows it to be a large one-story brick building with windows fitted into a saw tooth style roof that provided light.

Unfortunately local attempts to grow white mulberry trees and raise cocoons were unsuccessful. Success came only after raw silk was imported from China and Japan. Imported fibers were dyed to order at the various manufacturing locations and spun together to make thread. Finished thread was woven into fabric primarily at the Shamokin mill where the weaving took place.

The local silk industry suffered during the Great Depression and continued to decline during the 1930’s. The Shamokin plant closed in 1836 and the Gettysburg mill closed in 1938. At that same time the company declared bankruptcy and sold everything to a finance corporation who then sold the properties to Titan Metal in 1939. That ended the silk industry in Gettysburg.

If you work with wood finishes, you probably are familiar with shellac. It is quick drying and produces a fine finish that can be used as is or serves as a foundation for additional finishing.

But did you know that commercial shellac flakes and alcohol-based shellac solutions are composed of the crushed bodies of insects, the lac bug? The lac bug, Kerria lacca, is a parasitic insect whose larvae colonize trees, especially banyan trees, in India and Thailand, wrapping themselves in hard protective tubes of secreted resin that are collected and crushed to become shellac flakes. Shellac was used in the finishing of 18th-century violins and other wood varnishes and is still a popular wood finish readily available today.

A most vivid natural crimson pigment known as carmine comes from a beneficial scale insect, Dactylopius coccus, commonly referred to as cochineal. Known to the Aztecs long before the Spanish invaders, it is a primarily immobile parasitic insect that lives on cacti native to tropical and subtropical Mexico, South and North America. It is crushed to obtain the bright crimson dye, and its use dates back centuries. The dye was used in North America in the 15th century for dying fabrics. A potent red, painters favored it because of its resistance to fading in portraits.

Its body is bright red when dried, and is mixed with aluminum or calcium salts to make carmine dye also known as cochineal. Today carmine is primarily used as a "natural" colorant in food and lipstick and is listed as E120 or Natural Red 4. It takes a whopping 70,000 cochineal insects to make just one pound of carmine or cochineal dye. Today cochineal has been surpassed as a dye for cloth by a number of synthetic pigments.

Just think, some of the greatest achievements of human culture were based on the crushed bodies of insects.

Read other articles about controlling insects & garden pests