Grade 5 Nature Study
News Flash :- A New Insect Order Is Discovered
There was much excitement in the entomological world when a new order of insects was discovered in 2002. To find out more visit the National Geographic news page.
Silk Worm Research
Silkworms and Their Work
From Maker of Many Things
by Eva March Tappen
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Silkworms and Their Work
About silk there is something particularly agreeable. There are few people who do not like the sheen of a soft silk, the sparkle of light on a "taffeta," and the richness of the silk that "can stand alone." Its delicate rustle is charming, and the "feel" of it is a delight. It has not the chill of linen, the deadness of cotton, or the "scratchiness" of woolen. It pleases the eye, the ear, and the touch.
The caterpillars of a few butterflies and of many moths are spinners of fibers similar to silk. Among these last is the beautiful pale-green lunar moth. Spiders spin a lustrous fiber, and it is said that a lover of spiders succeeded, by a good deal of petting and attention, in getting considerable material from a company of them. Silkworms, however, are the only providers of real silk for the world. Once in a while glowing accounts are published of the ease with which they can be raised and the amount of money which can be made from them with very small capital. This business, however, like all other kinds of business, requires close attention and skill if it is to be a success. An expert has said that it needs more time to build a spool of silk than a locomotive.
The way to begin to raise silkworms is first of all to provide something for them to eat. They are very  particular about their bill of fare. The leaf of the osage orange will answer, but they like much better the leaf of the white mulberry. Then send to a reliable dealer for a quarter of an ounce of silkworm eggs. That sounds like a small order, but it will bring you nine or ten thousand eggs, ready to become sturdy little silkworms if all goes well with them.
Put them on a table with a top of wire netting covered with brown paper, and keep them comfortably warm. In a week or two, there will appear some little worms about an eighth of an inch long and covered with black hairs. These tiny worms have to become three inches or more in length, and they are expected to accomplish the feat in about a month. If a boy four feet tall should grow at the silkworm's rate for one month, he would become forty-eight feet tall. It is no wonder that the worms have to make a business of eating, or that the keeper has to make a business of providing them with food. They eat most of the time, and they make a queer little crackling sound while they are about it. They have from four to eight meals a day of mulberry leaves. The worms from a quarter of an ounce of eggs begin with one pound a day, and work up to between forty and fifty.
Silkworms like plenty of fresh air, and if they are to thrive, their table must be kept clean. A good way to manage this is to put over them paper full of holes large enough for them to climb through. Lay the leaves upon the paper; the worms will come up through the holes to eat, and the litter on their table can be cleared away.
As  the worms grow larger, the holes must be made larger. It is no wonder that their skins soon become too tight for them. They actually lose their appetite for a day or two, and they slip away to some quiet corner under the leaves, and plainly wish there were no other worms to bother them. Soon the skin comes off, and they make up for lost time so energetically that they have to drop their tight skins three times more before they are fully grown. Wet mulberry leaves must not be given them, or they will become sick and die, and there will be an end of the silkworm business from that quarter-ounce of eggs. They must have plenty of room on their table as well as in their skins. At first a tray or table two feet long and a little more than one foot wide will be large enough; but when they are full-grown, they will need about eighty square feet of table or shelves. At spinning time, even this will not be enough.
After the worms have shed their skins four times and then eaten as much as they possibly can for eight or ten days, they begin to feel as if they had had enough. They now eat very little and really become smaller. They are restless and wander about. Now and then they throw out threads of silk as fine as a spider's web. They know exactly what they want; each little worm wants to make a cocoon, and all they ask of you is to give them the right sort of place to make it in. When they live out of doors in freedom, they fasten their cocoons to twigs; and if you wish to give them what they like best, get plenty of dry twigs and weave them together in arches standing  over the shelves. Pretty soon you will see one worm after another climb up the twigs and select a place for its cocoon. Before long it throws out threads from its spinneret, a tiny opening near the mouth, and makes a kind of net to support the cocoon which it is about to weave.
The silkworm may have seemed greedy, but he did not eat one leaf too much for the task that lies before him. There is nothing lazy about him; and now he works with all his might, making his cocoon. He begins at the outside and shapes it like a particularly plump peanut of a clear, pale yellow. The silk is stiffened with a sort of gum as it comes out of the spinneret. The busy little worm works away, laying its threads in place in the form of a figure eight. For some time the cocoon is so thin that one can watch him. It is calculated that his tiny head makes sixty-nine movements every minute.
The covering grows thicker and the room for the silkworm grows smaller. After about seventy-two hours, put your ear to the cocoon, and if all is quiet within, it is completed and the worm is shut up within it. Strange things happen to him while he sleeps in the quiet of his silken bed, for he becomes a dry brown chrysalis without head or feet. Then other things even more marvelous come to pass, for in about three weeks the little creature pushes the threads apart at one end of the cocoon and comes out, not a silkworm at all, but a moth with head and wings and legs and eyes. This moth lays hundreds of eggs, and in less than three weeks it dies.
This is what the silkworm will do if it is left alone; but it is the business of the silk-raiser to see that it is not left alone. About eight days after the cocoon is begun, it is steamed or baked to kill the chrysalis so that it cannot make its way out and so spoil the silk. The quarter of an ounce of eggs will make about thirty pounds of cocoons. Now is the time to be specially watchful, for there is nothing in which rats and mice so delight as a plump, sweet chrysalis; and they care nothing whatever for the three or four thousand yards of silk that is wound about each one.
To take this silk off is a delicate piece of work. A single fiber is not much larger than the thread of a cobweb, and before the silk can be used, several threads must be united in one. First, the cocoon is soaked in warm water to loosen the gum that the worm used to stick its threads together. Ends of silk from half a dozen or more cocoons are brought together, run through a little hole in a guide, and wound on a reel as one thread. This needs skill and practice, for the reeled silk must be kept of the same size. The cocoon thread is so slender that, of course, it breaks very easily; and when this happens, another thread must be pieced on. Then, too, the inner silk of the cocoon is finer than the outer; so unless care is taken to add threads, the reeled silk will be irregular. The water must also be kept just warm enough to soften the gum, but not too hot.
The silk is taken off the reel, and the skeins are packed up in bales as if it were of no more value than  cotton. Indeed, it does not look nearly so pretty and attractive as a lap of pure white cotton, for it is stiff and gummy and has hardly any luster. Now it is sent to the manufacturer. It is soaked in hot soapy water for several hours, and it is drawn between plates so close together that, while they allow the silk to go through, they will not permit the least bit of roughness or dirt to pass. If the thread breaks, a tiny "faller," such as are used in cotton mills, falls down and stops the machine. The silk must now be twisted, subjected to two or three processes to increase its luster, and dyed,—and if you would like to feel as if you were paying a visit to a rainbow, go into a mill and watch the looms with their smooth, brilliant silks of all the colors that can be imagined. After the silk is woven, it is polished on lustering machines, singed to destroy all bits of free fibers or lint, freed of all threads that may project, and scoured if it is of a light color; then sold.
HOW SPUN SILK IS MADE
Every manufacturer saves everything he can, and even the waste silk which cannot be wound on reels is turned into a salable product. (See photo)
The moth whose cocoon provides most of our silk is called the "bombyx mori." There are others, however, and from some of these tussah silk, Yamamai, and Shantung pongee are woven. These wild moths produce a stronger thread, but it is much less smooth than that of the bombyx.
There is also a great amount of "wood silk," or artificial silk, on the market. To make this, wood pulp is dissolved in ether and squirted through fine jets into water. It is soon hard enough to be twisted into threads and woven. It makes an imitation of silk, bright and lustrous, but not wearing so well as the  silk of the silkworm. Nevertheless, for many purposes it is used as a substitute for silk, and many braids and passementeries are made of it. Then, too, there are the "mercerized" goods, which often closely resemble real silk, although there is not a thread of silk in them. It was discovered many years ago that if a piece of cotton cloth was boiled in caustic soda, it would become soft and thick and better able to receive delicate dyes. Unfortunately, it also shrank badly. At length it occurred to some one that the cloth might be kept from shrinking by being stretched out during the boiling in soda. He was delighted to find that this process made it more brilliant than many silks.
The threads that fasten the cocoon to the bush and those in the heart of the cocoon are often used, together with the fiber from any cocoons through which the worms have made their way out. This is real silk, of course, but it is made of short fibers which cannot be wound. It is carded and spun and made into fabric called "spun silk," which is used extensively for the heavier classes of goods. Then, too, silks are often "weighted"; that is, just before they are dyed, salts of iron or tin are added. One pound of silk will absorb two or three pounds of these chemicals, and will apparently be a heavy silk, while it is really thin and poor. Moreover, this metallic weighting rubs against the silk fiber and mysterious holes soon begin to appear. A wise "dry cleaner" will have nothing to do with such silks, lest he should be held responsible for these holes.
It  is this weighting which produces the peculiar rustle of taffeta; and if women would be satisfied with a taffeta that was soft and thin, the manufacturers would gladly leave out the salts of iron, and the silks would wear much better. Cotton is seldom mixed with the silk warp thread; but it is used as "filling" in a large class of goods with silk warp. The custom has arisen of advertising such goods as "silk," which of course is not a fair description of them. Advertisements sometimes give notice of amazing sales of "Shantung pongee," which has been made in American looms and is a very different article from the imported "wild silk" pongee.
With so many shams in the market, how is a woman to know what she is buying and whether it will wear? There are a few simple tests that are helpful. Ravel a piece of silk and examine the warp and woof. If they are of nearly the same size, the silk is not so likely to split. See how strong the thread is. Burn a thread. If it burns with a little flame, it is cotton. If it curls up and smells like burning wool, it is probably silk. Another test by fire is to burn a piece of the goods. If it is silk, it will curl up; if it is heavily weighted, it will keep its shape. If you boil a sample in caustic potash, all the silk in it will dissolve, but the cotton will remain. If the whole sample disappears, you may be sure that it was all silk.
Soft, finely woven silks are safest because they will not hold so much weighting. Crêpe de chine is made of a hard twisted thread and therefore wears well. Taffeta can carry a large amount of weighting,  and is always doubtful; it may wear well, and it may not. There is always a reason for a bargain sale of silks. The store may wish to clear out a collection of remnants or to get rid of a line of goods which are no longer to be carried; but aside from this, there is usually some defect in the goods themselves or else they have failed to please the fashionable whim of the moment. Silk is always silk, and if you want it, you must pay for it.
Silk was first made by the Chinese about 4,000 years ago. Silk thread is made from the cocoon of the silkworm moth (Bombyx mori), a small moth whose caterpillar eats the leaves of the mulberry tree. The white cocoon is dropped into boiling water, and silk thread is unwound. Each cocoon yields about 500 to 1,200 yards of silk.
According to Chinese legend, the first silk thread was made when a Chinese Empress was sitting under a mulberry tree, and a cocoon fell into her tea; she noticed the strong, silky threads of the cocoon uncoiling. It is said that Empress Si-Ling-Chi, the wife of Emperor Huang-ti then experimented with silkworms and developed the use of silk in weaving around 2400 B.C. (put this date on your timeline)
Silk soon became very important to the Chinese economy, and it remained a Chinese secret for thousands of years, due in part to the Great Wall of China. The Chinese traded precious silk fabric to the rest of the world via the Silk Road, an overland trade route from China through the deserts of Central Asia to the West. The secret methods of raising silkworms and making silk were brought to Japan in the 3rd century A.D.
For a printout on the silkworm moth (Bombyx mori), click here.
From Enchanted Learning http://members.enchantedlearning.com/inventors/page/s/silk.shtml accessed January 27, 2016
The eggs are laid by female moths and hatch within nine to 12 days, so the resulting type can have up to eight separate lifecycles throughout the year.
Barb's Handbook of Nature Study
Index for Insects
Ants – Spring ebook
Black Swallowtail – Spring Nature Study Continues
Caddisfly and Caddis worm - Summer Nature Study Continues
Cockroach – Autumn 2015
Crickets – Summer ebook and another cricket study
Dragonflies and Damselflies
Fireflies - Summer ebook
Gall Dwellers – More Nature Study Winter
Grasshoppers - Summer ebook
Insect Study with Bug’s Eye View Printable
Katydids - Summer ebook
Lacewing – Summer Nature Study Continues coming soon
Leaf Miners and Leaf Rollers – More Nature Study Autumn
Monarch Butterfly – More Nature Study Summer
Moths – Summer ebook and another moth study
Mosquitoes – Summer ebook
Mud Daubers – More Nature Study Summer
Winter Insects – Winter Wednesday ebook
Yellow Jackets – More Nature Study Summer
Iowa State University Entomology Gallery
Great photographs of insects.
Africanized Honey Bees
Lesson plans, grades K-12. Information and activity pages. Website maintained by University of Arizona.
The Butterfly Zone
Offers a "Butterfly Guide," information about a variety of butterflies, and how to attract butterflies to your garden.
The Wonderful World of Insects
Access to a broad range of information about insects and web links.
Visit this page to view the USPS stamp collection for insects (and a few spiders). The stamp images would be a great resource for a sorting activity to introduce classification.
Video and Photos
Ants are social insects of the family Formicidae and, along with the related wasps and bees, belong to the order Hymenoptera. More than 12,500 out of an estimated total of 22,000 species have been classified. They are easily identified by their elbowed antennae and a distinctive node-like structure that forms a slender waist.
Ants form colonies that range in size from a few dozen predatory individuals living in small natural cavities to highly organised colonies that may occupy large territories and consist of millions of individuals. Larger colonies consist mostly of sterile wingless females forming castes of "workers", "soldiers", or other specialised groups. Nearly all ant colonies also have some fertile males called "drones" and one or more fertile females called "queens". The colonies sometimes are described as superorganisms because the ants appear to operate as a unified entity, collectively working together to support the colony. (from wikipedia.org)
Ants - Nature's Secret Power
They have inhabited our planet for millions of years, and yet no living creature seems more alien to us. In this film Bert Hoelldobler brings us face-to-face with the mysterious world of these social insects.
Planet Ant - Life inside the Colony
Ant colonies are one of the wonders of nature - complex, organised and mysterious. Presented by George McGavin and Adam Hart, this film reveals the secret, underground world of the ant colony.
Lord of the Ants
This film profiles Harvard professor Edward Osborne Wilson who is an acclaimed advocate for ants, biological diversity, and the controversial extension of Darwinian ideas to human society.
Empire of the Desert Ants
This film looks at how a new honey ant queen wages an intense battle for survival as she attempts to build and defend her empire.
City of Ants
How do millions of simple creatures form a collective brain, make decisions and move like a single being? Enter the secret world of the most perfect society... the Superorganism.
Grasshopper & Ants
The story of La Fontaine tells that the grasshopper spent the summer singing and dancing while the ant was working to do her house and to gather food. This film shows us how these small beings really are.
Documentary about the world of the African driver ant, a sinister army of 20 million sisters which thrives by ravaging the forest, killing everything it can pin down.
Insect Classification Slideshow by Eve Varga
From Exploring Nature
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