When do silk worms form cocoons?
Silk
Silk moths lay eggs on specially prepared paper. The eggs hatch and the caterpillars (silkworms) are fed fresh mulberry leaves. After about 35 days and 4 moltings, the caterpillars are 10,000 times heavier than when hatched and are ready to begin spinning a cocoon. A straw frame is placed over the tray of caterpillars, and each caterpillar begins spinning a cocoon by moving its head in a pattern. Two glands produce liquid silk and force it through openings in the head called spinnerets. Liquid silk is coated in sericin, a water-soluble protective gum, and solidifies on contact with the air. Within 2–3 days, the caterpillar spins about 1 mile of filament and is completely encased in a cocoon. The silk farmers then heat the cocoons to kill them, leaving some to metamorphose into moths to breed the next generation of caterpillars. Harvested cocoons are then soaked in boiling water to soften the sericin holding the silk fibers together in a cocoon shape. The fibers are then unwound to produce a continuous thread. Since a single thread is too fine and fragile for commercial use, anywhere from three to ten strands are spun together to form a single thread of silk.
Acorn worm
Acorn worms are dioecious, having separate biological sexes, although at least some species are also capable of asexual reproduction. They have paired gonads, which lie close to the pharynx and release the gametes through a small pore near to the gill slits. The female lays a large number of eggs embedded in a gelatinous mass of mucus, which are then externally fertilized by the male before water currents break up the mass and disperse the individual eggs.
In most species, the eggs hatch into planktonic larvae with elongated bodies covered in cilia. In some species, these develop directly into adults, but in others, there is a free-swimming intermediate stage referred to as a "tornaria" larva. These are very similar in appearance to the bipinnaria larvae of starfishes, with convoluted bands of cilia running around the body. Since the embryonic development of the blastula within the egg is also very similar to that of echinoderms, this suggests a close phylogenetic link between the two groups.
Cotesia congregata
Adult wasps lay their eggs in tobacco hornworm ("Manduca sexta") larvae in their 2nd or 3rd instar (each instar is a stage between moltings, i.e. the second instar is the life stage after the first molt and before the second molting) and at the same time injects symbiotic viruses into the hemocoel of the host along with some venom. The viruses knock down the internal defensive responses of the hornworm. The eggs hatch in the host hemocoel within two to three days and simultaneously release special cells from the egg's serosa. These special cells, called teratocytes, grow to become giant cells visible to the naked eye. The teratocytes secrete hormones which work in tandem with the virus and the wasp venom to arrest the development of the host. Following hatching in the caterpillar, the wasp larvae will undergo 2 molts inside the host caterpillar’s hemocoel and, after 12 to 16 days post oviposition, the 3rd instar wasp larvae will emerge from the caterpillar and spin cocoons from which the adult wasps fly about 4 to 8 days later.
Tussar silk
In order to kill the silkworms, the cocoons are dried in the sun. A variation of the process exists in which the silkworms are allowed to leave before the cocoons are soaked in boiling water to soften the silk and then reeled. Single-shelled, oval-shaped cocoons are collected and then boiled to extract the silk yarn. Boiling is a very important part in the manufacturing of silk, as it softens the cocoon and makes the extraction of silk easier. In conventional sericulture, the cocoons are boiled with the larvae still inside; however, if the cocoons are boiled after the larvae have left them, the silk made is then called "non-violent silk" or "Ahimsa silk". In China, the silks are given different names when silkworms are reared on different plants, as the diet of the silkworms has an effect on the quality of the silk. For example, silk from larvae on the wild mulberry is called "zhe", while those on the oak "Quercus dentata" produce "hu".
Spider web
Spiders produce silk from their spinneret glands located at the tip of their abdomen. Each gland produces a thread for a special purpose – for example a trailed safety line, sticky silk for trapping prey or fine silk for wrapping it. Spiders use different gland types to produce different silks, and some spiders are capable of producing up to eight different silks during their lifetime.
Silk comforter
The cocoons are first boiled to loosen the sericin holding the filaments together and kill the silkworm. Each cocoon is stretched by hand on a U-shaped wooden rack, and the ball of thread becomes a sheet of tangled fibers. This sheet is then hand-stretched again on a larger rack, along with several other cocoons to make a thick, cottony bundle called silk floss. It takes hundreds of these bundles to make a silk comforter.
Enrico Verson
A physician, Verson worked initially at the experimental station of Gorigia before founding the first research station on the silkworm in the world, the Stazione Bacologica Sperimentale in 1871. Verson made many observations on the biology of the silkworm and made anatomical discoveries such as the cells of Verson (apical cells of the genital apparatus of certain insects) and glands of Verson (glands of the exoskeleton (skin) of the caterpillars playing an important part in the moult).
History of clothing and textiles
The earliest evidence of silk production in China was found at the sites of Yangshao culture in Xia, Shanxi, where a cocoon of bombyx mori, the domesticated silkworm, cut in half by a sharp knife is dated to between 5000 and 3000 BC. Fragments of primitive looms are also seen from the sites of Hemudu culture in Yuyao, Zhejiang, dated to about 4000 BC. Scraps of silk were found in a Liangzhu culture site at Qianshanyang in Huzhou, Zhejiang, dating back to 2700 BC. Other fragments have been recovered from royal tombs in the [Shang Dynasty] (c. 1600 – c. 1046 BC).
Samea multiplicalis
Caterpillars construct a silk cocoon inside of a leaf petiole on their host plant in order to pupate. Pupation lasts between four to ten days, with females developing faster than males. Time spent in this stage of development is not dependent on larval nutrition.
After they emerge from their cocoons, adult salvinia stem-borer moths spend the rest of their three- or four-week life span around their host plants, mating and laying eggs. Female moths lay an average of 150 eggs over the course of several days on the surfaces of host plant leaves or among hairs or leaflet structures. Moths prefer the host plant "P. stratiotes" for laying eggs due to its structure which provides abundant oviposition surfaces. Moths are not known to oviposit on "E. crassipes". Adults are tan with darker markings on both sets of wings and a wingspan of about 20 mm. Adult size is not significantly affected by larval nutrition levels, however insufficient nitrogen during larval development does lead to reduced egg production in female moths.
Textile manufacturing by pre-industrial methods
Silk moths lay eggs on specially prepared paper. The eggs hatch and the caterpillars (silkworms) are fed on fresh mulberry leaves. After about 35 days and 4 moltings, the caterpillars are 10,000 times heavier than when hatched and are ready to begin spinning a cocoon. A straw frame is placed over the tray of caterpillars, and each caterpillar begins spinning a cocoon by moving its head in a pattern. Two glands produce liquid silk and force it through openings in the head called spinnerets. Liquid silk is coated in sericin, a water-soluble protective gum, and solidifies on contact with the air. Within 2–3 days, the caterpillar spins about 1 mile of filament and is completely encased in a cocoon.
Little spiderhunter
The breeding season in northeastern India is March to September but mainly May to August. In southern India it breeds from December to August. Two eggs are the usual clutch. The nest is a compact cup attached under a leaf of banana or similar broad leaved plant. The nest is suspended from the underside of the leaf using 150 or so "pop-rivets" of cobwebs and vegetable fibre, a unique method of using spider silk for animal architecture. 
It is suspected that Hodgson's hawk-cuckoo and violet cuckoo are brood parasites on this species in India.
History of silk
The writings of Confucius and Chinese tradition recount that, in about 3000 BC, a silk worm's cocoon fell into the tea cup of the empress Leizu. Wishing to extract it from her drink, the 14-year-old girl began to unroll the thread of the cocoon.
Bombyx mori
The cocoon is made of a thread of raw silk from 300 to about 900 m (1,000 to 3,000 ft) long. The fibers are very fine and lustrous, about 10 μm (0.0004 in) in diameter. About 2,000 to 3,000 cocoons are required to make a pound of silk (0.4 kg). At least 70 million pounds of raw silk are produced each year, requiring nearly 10 billion cocoons.
Chrysiridia rhipheus
After completing all but its last moult, the caterpillar spins a cocoon out of silk. The cocoon can be in the tree crown or between two leaves, but is most often near the ground, between moss and bark. It is an open network cocoon with large and irregular mesh. In the warm season, the cocoon takes about 10 hours to spin, the metamorphosis takes place about 29 hours later and lasts about 6 minutes. These durations are slightly longer in the cold season. The chrysalis stage lasts 17 days in November, the warmest month, and 23 days in July, the coldest month. Five to six days before eclosion, the motifs of the wings start to become visible. The moth emerges during the night or in low light, by splitting the pupal case from the top. Once out of the pupal exuvia (the pupal exoskeleton), the moth finds a horizontal surface, from which it suspends itself by its four anterior legs. The wings are deployed in about 10 minutes, by pumping haemolymph into the wing veins. The moth then beats them a few times, waits 45 minutes to let them harden, then beats them lightly again. The moth finally takes flight between one-and-a-half and two hours later.
Phleophagan chestnut moth
The larvae live in the lower layer of the bark of chestnut just above and encroaching upon the cambium. The mine is slender and serpentine, often doubling upon itself and broadening out to twice or more in width in early spring, when the larva reaches maturity. Full-grown larvae leave the bark and fall to the ground where they makes a closely woven, reddish brown cocoon amongst the rubbish, often boring down a few inches in the loose surface soil to find a suitable moist place on the underside of an old leaf or twig. The cocoon is oval and flattened,
Syllis prolifera
"S. prolifera" is a "stolonate" worm and has an unusual life cycle. When the worm has reached a length of about forty segments, the posterior portion of the worm develops into a stolon inside which the gonads mature. The stolon is either female (pale orange) or male (whitish) and becomes a storage receptacle for the eggs or sperm. Breeding is regulated by the phases of the moon, and when the breeding period arrives, the stolon becomes detached and joins others to swarm in the water column, in a process known as "epitoky". Here the gametes are released and the stolon dies. Meanwhile, the parent worm remains on the seabed and starts to grow a new stolon which is ready for release some 28 days later.
Scytodes thoracica
This particular spitting spider features the presence of silk glands in its cephalothorax. Besides the silk glands in its abdomen, the spider also has silk glands connected with its venom glands. In this way the spider has the ability to make venomous silk. Other arachnids may also have silk glands in their cephalothorax, such as the pseudoscorpions.
Entomophagy
Cave paintings in Altamira, north Spain, which have been dated from about 30,000 to 9,000 BC, depict the collection of edible insects and wild bee nests, suggesting a possibly entomophagous society. Cocoons of wild silkworm ("Triuncina religiosae") were found in ruins in the Shanxi province of China, from 2,000 to 2,500 years BC. The cocoons were discovered with large holes in them, suggesting the pupae were eaten. Many ancient entomophagy practices have changed little over time compared with other agricultural practices, leading to the development of modern traditional entomophagy.
Silk
Silks derived from "Bombyx mori" are generally made of two parts: the silk fibroin fiber which contains a light chain of 25kDa and a heavy chain of 350kDa (or 390kDa) linked by a single disulfide bond and a glue-like protein, sericin, comprising 25 to 30 percentage by weight. Silk fibroin contains hydrophobic beta sheet blocks, interrupted by small hydrophilic groups. And the beta-sheets contribute much to the high mechanical strength of silk fibers, which achieves 740 MPa, tens of times that of poly(lactic acid) and hundreds of times that of collagen. This impressive mechanical strength has made silk fibroin very competitive for applications in biomaterials. Indeed, silk fibers have found their way into tendon tissue engineering, where mechanical properties matter greatly. In addition, mechanical properties of silks from various kinds of silkworms vary widely, which provides more choices for their use in tissue engineering.
Pupa
Cocoons may be tough or soft, opaque or translucent, solid or meshlike, of various colors, or composed of multiple layers, depending on the type of insect larva producing it. Many moth caterpillars shed the larval hairs (setae) and incorporate them into the cocoon; if these are urticating hairs then the cocoon is also irritating to the touch. Some larvae attach small twigs, fecal pellets or pieces of vegetation to the outside of their cocoon in an attempt to disguise it from predators. Others spin their cocoon in a concealed location—on the underside of a leaf, in a crevice, down near the base of a tree trunk, suspended from a twig or concealed in the leaf litter.
Ahimsa silk
From a short-run economic standpoint, it is difficult to make the argument for peace silk as it requires 10 extra days in the process to let the larvae grow and the moths to hatch out of the cocoons. In contrast, the less humane process takes about 15 minutes. At this later stage the cocoon yields one-sixth of the filament. This inflates the cost of nonviolent silk, which is priced at roughly 6,000 rupees (US$92) per kilogram—about twice the price of the regular kind.
Wild silk
Wild silks are often referred to in India as 'Vanya' silks: The term 'Vanya' is of Sanskrit origin, meaning untamed, wild, or forest-based. Muga, Tasar, and Eri silkworms are not fully tamed and the world lovingly calls the silks they produce as 'wild silks'.
India produces four kinds of silk: mulberry, tasar, muga and eri. The silkworm "Bombyx mori" is fed on mulberry leaves cultivated in plantations. Silkworms are also found wild on forest trees, e.g "Antheraea paphia" which produces the tasar silk (Tussah). "Antheraea paphia" feeds on several trees such as "Anogeissus latifolia", "Terminalia tomentosa", "T. arjuna" ("Terminalia arjuna"), "Lagerstroemia parviflora" and "Madhuca indica". Wild silkworm "Antheraea assamensis" produces muga silk, and another wild silkworm "Philosamia synthia ricini" (= "Samia cynthia") produces eri silk. The estimated annual production of tasar silk is 130 tonnes. Production of other types of silk exceeds 10 000 tonnes (Gupta 1994).
In 2015, Adarsh Gupta K of Nagaraju's research team at Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India, discovered the complete sequence and the protein structure of Muga Silk Fibroin and published it in "Scientific Reports".
Opodiphthera eucalypti
When the caterpillar is fully mature it spins a dark brown silken cocoon on a branch which usually has a leaf to protect it with. When spinning is complete, the caterpillar sheds its final skin and takes the form of its pupall life stage. Within a day of spinning completion, the cocoon sets to a hard waterproof shell with a rough exterior and a smooth interior wall. Air holes can be seen along the side of the cocoon indicating that the cocoon is probably otherwise airtight. The moth usually emerges from the cocoon the following year (in Spring or early Summer) but depending on weather conditions can stay in the cocoon from anywhere between two and five years. One case has even been recorded of a moth emerging out of the cocoon after 10 years.
Spider silk
Silk fibre is a two-compound pyriform secretion, spun into patterns (called "attachment discs") that are employed to adhere silk threads to various surfaces using a minimum of silk substrate. The pyriform threads polymerise under ambient conditions, become functional immediately, and are usable indefinitely, remaining biodegradable, versatile and compatible with numerous other materials in the environment. The adhesive and durability properties of the attachment disc are controlled by functions within the spinnerets. Some adhesive properties of the silk resemble glue, consisting of microfibrils and lipid enclosures.
Insect farming
Silkworms, the caterpillars of the domestic silkmoth, are kept to produce silk, an elastic fiber made when they are in the process of creating a cocoon. Silk is commonly regarded as a major cash crop and is used in the crafting of many textiles.
Orbiculariae
Whether spiders that weave true orb webs form a coherent group, and so should be classified together, is a question that has a long history. Two groups of spiders that spin orb webs are the Uloboridae and the Araneidae. Although their webs have a very similar overall architecture, the sticky catching threads are created in different ways. Uloborid spiders have a cribellum – a flat plate from which a particular kind of silk emerges – and a calamistrum – a structure formed of bristles on the metatarsus of the fourth leg, used to "comb" the cribellate silk into extremely fine strands that are adhesive without having any "glue" present. Araneid spiders have silk-producing organs that add fine droplets of a glue-like substance to silk of normal thickness to create viscid silk. (Spiders that do not spin orb webs can also be divided into those that produce cribellate silk and those that produce viscid silk.)
Sericin
Silk is a fibre produced by the silkworm in production of its cocoon. It consists mainly of two proteins, fibroin and sericin. Silk consists of 70–80% fibroin and 20–30% sericin; fibroin being the structural center of the silk, and sericin being the gum coating the fibres and allowing them to stick to each other.
Silk
Silk fibers from the "Bombyx mori" silkworm have a triangular cross section with rounded corners, 5–10 μm wide. The fibroin-heavy chain is composed mostly of beta-sheets, due to a 59-mer amino acid repeat sequence with some variations. The flat surfaces of the fibrils reflect light at many angles, giving silk a natural sheen. The cross-section from other silkworms can vary in shape and diameter: crescent-like for "Anaphe" and elongated wedge for "tussah". Silkworm fibers are naturally extruded from two silkworm glands as a pair of primary filaments (brin), which are stuck together, with sericin proteins that act like glue, to form a bave. Bave diameters for tussah silk can reach 65 μm. See cited reference for cross-sectional SEM photographs.
Eastern tent caterpillar
The newly hatched caterpillars initiate the construction of a silk tent soon after emerging. They typically aggregate at the tent site throughout their larval stage, expanding the tent each day to accommodate their increasing size. Under field conditions, the caterpillars feed three times each day, just before dawn, at midafternoon, and in the evening after sunset. During each bout of feeding, the caterpillars emerge from the tent, add silk to the structure, move to distant feeding sites "en masse", feed, and then return immediately to the tent where they rest until the next activity period. The exception to this feeding pattern occurs in the last instar, when the caterpillars feed only at night. The insect has six larval instars. At the last stage, the caterpillars disperse and each constructs a cocoon in a protected place. The adult moths, or imagoes, emerge about two weeks later. They are strictly nocturnal and start flying after nightfall, coming to rest within a few hours of dawn. Mating and oviposition typically occur on the day the moths emerge from their cocoons; the females die soon thereafter.
Cocoonase
Cocoonase is a trypsin-like proteolytic enzyme produced by silkworms (of both "Bombyx" and "Antheraea" species) as they near the final stages of their metamorphosis. It is produced by cells in the proboscis and exuded onto the galeae. Its function is to weaken the fibers of the cocoon, thereby facilitating the emergence of the adult insect.
Coho salmon
The eggs hatch in the late winter or early spring after six to seven weeks in the redd. Once hatched, they remain mostly immobile in the redd during the alevin life stage, which lasts for 6–7 weeks. Alevin no longer have the protective egg shell, or chorion, and rely on their yolk sacs for nourishment during growth. The alevin life stage is very sensitive to aquatic and sedimental contaminants. When the yolk sac is completely resorbed, the alevin leaves the redd. Young coho spend one to two years in their freshwater natal streams, often spending the first winter in off-channel sloughs, before transforming to the smolt stage. Smolts are generally and as their parr marks fade and the adult's characteristic silver scales start to dominate. Smolts migrate to the ocean from late March through July. Some fish leave fresh water in the spring, spend summer in brackish estuarine ponds, and then return to fresh water in the fall. Coho salmon live in salt water for one to three years before returning to spawn. Some precocious males, known as "jacks", return as two-year-old spawners. Spawning males develop kypes, which are strongly hooked snouts and large teeth.
Silk comforter
Silk comes from the cocoons of the silkworm, which feeds off mulberry trees in subtropical climates. When the cocoon is boiled, the hard cocoon becomes a loose ball of strong, flexible filament measuring over 1,000 meters. Usually, this ball is uncoiled and wrapped on a spindle for use in the textile industry. Silk is used for making everything from clothing to rugs. During silk comforter production, however, the silk filament is not unraveled, but rather stretched into a flat tangled web and layered to form silk floss, which will fill the comforter.
Macropis nuda
After the larval feeding period, pupae spin the cocoons in which they will hibernate until the next spring. Cocoons completely occupy the cells, and strongly adhere to the sides of the cell, but not the closure. There is a small hole near the apex of the cocoon, opening to the soil closure of the cell. This allows exchange of oxygen and carbon dioxide as the waxy oil coating the cell and the silk of the cocoon does not allow for gas movement. Not only does the cocoon allow safety from the cold of the winter, it may also serve as a barricade to protect against parasites and predators.
Ahimsa silk
While "Bombyx mori" are the preferred species for creating ahimsa silk, there are a few other types of species that fall under the category of ahimsa silk, which is defined not necessarily by the species of the moth involved but by the methods for harvesting the cocoon. The other types of silkworm that are used for this process are a subspecies of the ailanthus silkmoth and several types of tussah or tasar moths: the Chinese tussah moth, the Indian tasar moth, and the muga moth.
Cochliomyia hominivorax
Screw-worm females lay 250-500 eggs in the exposed flesh of warm-blooded animals, including humans, such as in wounds and the navels of newborn animals. The larvae hatch and burrow into the surrounding tissue as they feed. Should the wound be disturbed during this time, the larvae burrow or "screw" deeper into the flesh, thus the insect's name. The maggots are capable of causing severe tissue damage or even death to the host. About three to seven days after hatching, the larvae fall to the ground to pupate. The pupae reach the adult stage about seven days later. Female screw-worm flies mate four to five days after hatching. The entire lifecycle is around 20 days. A female can lay up to 3,000 eggs and fly up to during her life.
Samia cynthia
The eri silk worm is the only completely domesticated silkworm other than "Bombyx mori". The silk is extremely durable, but cannot be easily reeled off the cocoon and is thus spun like cotton or wool.
Kazuo Kadonaga
In his silk pieces, Kadonaga builds wooden grids from pine or cedar wood. He then releases on them silkworms that have been fed and readied for making cocoons. The worms then explore the structures Kadonaga made for them, and settle in the different crannies throughout.
Baluchari Sari
Cultivation of cocoons: Since the discovery so many years ago that the fibre or filament composing the cocoon of the silkworm can be constructed into a beautiful and durable fabric, silkworms have been bred for the sole purpose of producing raw silk.
Bombyx mori
Silkworm pupae are eaten in some cultures.In China, a legend indicates the discovery of the silkworm's silk was by an ancient empress Lei Zu, the wife of the Yellow Emperor and the daughter of XiLing-Shi. She was drinking tea under a tree when a silk cocoon fell into her tea. As she picked it out and started to wrap the silk thread around her finger, she slowly felt a warm sensation. When the silk ran out, she saw a small larva. In an instant, she realized this caterpillar larva was the source of the silk. She taught this to the people and it became widespread. Many more legends about the silkworm are told.
Silky pocket mouse
The silky pocket mouse is mainly nocturnal and lives in a burrow by day. In warmer weather it consumes cached food in the afternoon before emerging on the surface to forage in the evening. It mostly collects grass and weed seeds but also eats some green leafy material. It takes the husks off the seeds before storing them in its cheek pouches and carrying them back to its burrow where they are cached. A silky pocket mouse collects an average of of seed on each sortie. When a pile of was deposited near a burrow (sufficient for maintenance for up to 10 days), the pocket mouse collected and stored it all in one night, and still emerged to forage on succeeding nights. In cold weather it occasionally forages by day, and in really bad weather it may not come out of the burrow for several days.
Genetically modified organism
Silkworm, the larvae stage of "Bombyx mori," is an economically important insect in sericulture. Scientists are developing strategies to enhance silk quality and quantity. There is also potential to use the silk producing machinery to make other valuable proteins. Proteins currently developed to be expressed by silkworms include; human serum albumin, human collagen α-chain, mouse monoclonal antibody and N-glycanase. Silkworms have been created that produce spider silk, a stronger but extremely difficult to harvest silk, and even novel silks.
Corn silk
Corn silk is part stigma and part style, providing a female flower surface to which pollen grains can adhere and defining the lengthy path through which the pollen must transmit its genetic material. The stigma is the very tip of the corn silk, which has a larger number of hairs to help pollen to adhere to it. Kernel formation in the cob requires pollination of the external corn silk by wind or insects. Usually several grains of pollen adhere, but only one will successfully participate in fertilization of the ovule to form a corn kernel.
Nephila clavata
Researchers, led by Masao Nakagaki, at Shinshu University, Japan have succeeded in creating a silk thread that is stronger, softer and more durable than conventional silk by injecting silkworm eggs with genes of the spider. The silkworms that hatch weave cocoons containing 10% spider protein. The dragline silk is said to have many uses, such as: bulletproof vests, sutures after an operation, tennis rackets, fishing line, and nets. A Japanese manufacturer named Okamoto had begun developing commercial applications for the spider silk, and planned to release extra-thin, durable spider socks by year 2010.
Acorn worm
Acorn worms continually form new gill slits as they grow in size, with some older individuals having more than a hundred on each side. Each slit consists of a branchial chamber opening to the pharynx through a U-shaped cleft and to the exterior through a dorso-lateral pore (see diagram below). Cilia push water through the slits, maintaining a constant flow. The tissues surrounding the slits are well supplied with blood sinuses.
Araneus marmoreus
Egg cocoons, which contain several hundred eggs, are generally deposited in October and are constructed of white silk formed in a flattened sphere. Immature spiders emerge from the cocoons in spring. Adults are seen from midsummer until the first hard freeze of fall.
Animal husbandry
Sericulture, the rearing of silkworms, was first adopted by the Chinese during the Shang dynasty. The only species farmed commercially is the domesticated silkmoth. When it spins its cocoon, each larva produces an exceedingly long, slender thread of silk. The larvae feed on mulberry leaves and in Europe, only one generation is normally raised each year as this is a deciduous tree. In China, Korea and Japan however, two generations are normal, and in the tropics, multiple generations are expected. Most production of silk occurs in the Far East, with a synthetic diet being used to rear the silkworms in Japan.
Limacodidae
The final instar constructs a silk cocoon and hardens it with calcium oxalate excreted from its Malpighian tubules. Cocoons have a circular escape hatch, formed from a line of weakness in the silk matrix. It is forced open just prior to emergence of the adult.
Commercial butterfly breeding
Commercial breeding of Lepidoptera has a long history. The "Bombyx mori" (Latin: "silkworm of the mulberry tree"), The practice of breeding silkworms for the production of raw silk, also known as Sericulture, has been underway for at least 5,000 years in China. It is dependent on humans for its reproduction and does not occur naturally in the wild. The silkworm was domesticated from the wild silkmoth "Bombyx mandarina" which ranges from northern India to northern China, Korea, Japan, and the far eastern regions of Russia. The domesticated silkworm derives from Chinese rather than Japanese or Korean stock. Silkworms were unlikely to have been domestically bred before the Neolithic age; before then, the tools required to facilitate the manufacturing of larger quantities of silk thread had not been developed. The domesticated "B. mori" and the wild "B. mandarina" can still breed and sometimes produce hybrids...
Oligotoma nigra
The entire life cycle of the black webspinner is typically completed within a year. They are a hemimetabolous insect species, meaning that they have incomplete metamorphosis. During developmental stages the nymphs produce silk from silk glands. The glands are located on the basal segment of the foretarsus. they use this ability to create silk tunnels for protection from predators and to store food. Eggs are laid within the silk tunnels. When the nymphs hatch they expand the network of tunnels. This network continues to expand as the insect matures. The vast majority of their life is spent within the silk tunnel.
Gonometa postica
The species has become notable for producing a fine quality wild silk in its cocoon. The cocoons are harvested commercially in Namibia, Botswana, Kenya and South Africa, and the species also occurs in Zimbabwe and Mozambique. An Oxford University research team found that the cocoon surfaces are covered with calcium oxalate, hindering their commercial utilisation. They discovered and patented a method known as demineralizing using a warm solution of EDTA (ethylenediaminetetraacetic acid), softening the cocoons by dissolving the sericin, permitting the silk to be unravelled with no appreciable loss of strength. Cocoons are also sexually dimorphic, with those of females being roughly twice the size of those of males, thus yielding more silk. Sex ratios in natural populations will clearly play a large role in the harvesting of cocoons.
Hornet moth
"S. apiformis" larvae hatch from September to May and spend two or three years in the larval stage, overwintering as larvae. The larvae are mostly found around the roots of host trees. Prior to pupating, the larvae bore up to ten centimeters into the trunk of the host tree leaving a thin layer of bark over the entrance to disguise the tunnel. Once inside the larva builds a cocoon from silk and excavated tree material.
Lesser wax moth
The pupae are 11 mm in length and are a yellow tan color. The silk cocoon is white but is usually covered with frass. On average, the adults emerge after 37 days, but pupation can take up to 2 months.
Leucochloridium paradoxum
The worm in its larval, miracidia stage, travels into the digestive system of a snail to develop into the next stage,
a sporocyst. The sporocyst grows into long tubes to form swollen "broodsacs" filled with tens to hundreds of cercariae. These broodsacs invade the snail's tentacles (preferring the left, when available), causing a brilliant transformation of the tentacles into a swollen, pulsating, colorful display that mimics the appearance of a caterpillar or grub. The broodsacs seem to pulsate in response to light intensity, and in total darkness they do not pulse at all. The infection of the tentacles of the eyes seems to inhibit the perception of light intensity. Whereas uninfected snails seek dark areas to prevent predation, infected snails have a deficit in light detection, and are more likely to become exposed to predators, such as birds. In a study done in Poland, 53% of infected snails stayed in more open places longer, sat on higher vegetation, and stayed in better lit places than uninfected snails. Only 28% of the uninfected snails remained fully exposed for the duration of the observation period. Birds are the definitive hosts where the cercariae develop into adult distomes in the digestive system of the bird. These adult forms sexually reproduce and lay eggs that are released from the host via the bird's excretory system. These droppings are then consumed by snails to complete the life cycle of this parasitic worm.
Wild silk
Commercially reared silkworms of the species "Bombyx mori" (Linnaeus, 1758) are normally killed before the pupae emerge, either by pricking them with a needle or dipping the cocoons into boiling water, thus allowing the whole cocoon to be unravelled as one continuous thread. This allows a much finer cloth to be woven from the silk.
Silk industry of Cheshire
Silk is a naturally produced fibre obtained from many species of the silk moth. In 1700 the favoured silk was produced by a moth (Bombyx mori), that used it to spin a closed cocoon to protect her larvae. These fed on the mulberry leaf which was grown in Italy. Silk fibres from the "Bombyx mori" silkworm have a triangular cross section with rounded corners, 5-10 μm wide. The silk is a protein called fibroin and it was cemented in place by the use of a gum, another protein called sericin. The cocoons were harvested and placed in troughs of hot water that dissolved the gum and allowed the single thread to be wound into a skein.
Kraig Biocraft Laboratories
The method used to genetically modify the silkworm uses the PiggyBac Transposon vector discovered and developed by Dr. Fraser at the University of Notre Dame. Specific sequences of spider silk DNA are inserted into the genetic makeup of the silkworm to create a strain of the insect that now produces the spider protein. They are able to customize the sequences that are inserted into the silkworm, thus giving the ability to customize the resulting silkworm's thread strength and flexibility. To ensure the silkworm has been genetically modified, a gene was attached that gave the transgenic silkworms red glowing eyes.
The thread produced by the transgenic silkworms is close to the strength and flexibility of the native spider. Strength relative to native spider silk is 80%. Kraig Biocraft Laboratories is not the first to create transgenic silkworms incorporating spider silk proteins. Where Kraig Labs has succeeded is that the spider silk proteins are integrated structurally into the transgenic silkworm fiber.
Santuk Silk Farm
Santuk Silk Farm is a silk farm, located about 11 miles (18km) southeast of Kampong Thom City, Cambodia, near the village of Kakaoh. The farm, established by Vietnam War veteran Bud Gibbons in 2006, demonstrates the process of the silk worm, from its earliest stages, from egg to cocoon. The farm employs some 15 girls to weave the raw silk into thread; they make scarves and other items, sold in the shop on site.
Western conifer seed bug
The eggs are laid in small groups on the needles or leaf stems of its host plants, and hatch in spring. The nymphs go through 5 instar stages before moulting into adults. In the United States, the species is univoltine, but in southern Europe, it completes two generations a year, and in tropical Mexico even three. In the northern parts of its range, these bugs start to move about widely by September or so to seek crevices for overwintering; they may become a nuisance in areas with extensive conifer woods, as they will sometimes enter houses in considerable numbers. They have the potential to become structural pests, as it has been found that they will sometimes pierce PEX tubing with their mouthparts, resulting in leakage.
Silk comforter
Once enough silk cocoons have been stretched into bundles, the comforter begins to take shape. Workers grab the edges of the bundle and stretch it wide to match the dimensions of the desired comforter, and layer by layer the comforter begins to take shape. It can take anywhere between 100 and 400 of these thin layers to make a comforter, depending on bed dimensions and desired thickness. Since it takes many cocoons to make each layer, a silk comforter may be composed of thousands of silk cocoons.
Scotch bonnet (sea snail)
Growth is slow, and the veligers are carried by the ocean currents for up to 14 weeks. As the veligers mature, they develop their first shell (the smooth protoconch) and turn into very small juvenile snails, at which point they sink to the ocean floor. As is the case in all shelled mollusks, the mantle is what secretes the shell; shell growth begins at what will later become the apex of the shell, and typically rotates clockwise. As the animal gradually matures, the mantle continues to secrete shell material. Scotch bonnets complete maturation in one to six years. However, some have lived more than six years.
Gynaephora groenlandica
These cocoons are made of silk and consist of two layers, into which larval hairs are incorporated. In a 1995 study of experimentally caged larvae in the Canadian High Arctic Archipelago, 81% of larvae spun hibernacula.
Bombyx mori
Mulberry silkworms can be categorized into three different but connected groups or types. The major groups of silkworms fall under the univoltine ("uni-"=one, "voltine"=brood frequency) and bivoltine categories. The univoltine breed is generally linked with the geographical area within greater Europe. The eggs of this type hibernate during winter due to the cold climate, and cross-fertilize only by spring, generating silk only once annually. The second type is called bivoltine and is normally found in China, Japan, and Korea. The breeding process of this type takes place twice annually, a feat made possible through the slightly warmer climates and the resulting two life cycles. The polyvoltine type of mulberry silkworm can only be found in the tropics. The eggs are laid by female moths and hatch within nine to 12 days, so the resulting type can have up to eight separate life cycles throughout the year.
Silk
Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the cocoons of the larvae of the mulberry silkworm "Bombyx mori" reared in captivity (sericulture). The shimmering appearance of silk is due to the triangular prism-like structure of the silk fibre, which allows silk cloth to refract incoming light at different angles, thus producing different colors.
Thai silk
In its original cocoon form, raw silk is bumpy and irregular. Thai weavers separate the completed cocoons from the mulberry bush and soak them in a vat of boiling water to separate the silk thread from the caterpillar inside the cocoon.
Silk
The process of silk production is known as sericulture. The entire production process of silk can be divided into several steps which are typically handled by different entities. Extracting raw silk starts by cultivating the silkworms on mulberry leaves. Once the worms start pupating in their cocoons, these are dissolved in boiling water in order for individual long fibres to be extracted and fed into the spinning reel.
Mayumaro
Mayumaro was created in 2011 for the National Cultural Festival. His motif is a cocoon because silkworm cocoons are used to make silk, which is then used to make cloth, for example "tangotime, nishijin ori", or "kyouyuu zenn". The design was chosen by the public from over 2,000 candidates from Japan and other countries.
Earthworm
Copulation and reproduction are separate processes in earthworms. The mating pair overlap front ends ventrally and each exchanges sperm with the other. The clitellum becomes very reddish to pinkish in color. Some time after copulation, long after the worms have separated, the clitellum (behind the spermathecae) secretes material which forms a ring around the worm. The worm then backs out of the ring, and as it does so, it injects its own eggs and the other worm's sperm into it. As the worm slips out of the ring, the ends of the cocoon seal to form a vaguely onion-shaped incubator (cocoon) in which the embryonic worms develop.
Welfare of farmed insects
Many vegans avoid honey and silk because these require insect farming, even though the insects are not eaten. Silk production involves boiling silk worms alive in their cocoons.
Silk industry in China
China is the world's largest silk producer. The vast majority of Chinese silk originates from the mulberry silkworms ("Bombyx mori"). During the larval stage of its life-cycle, the insects feeds on the leaves of mulberry trees. Non-mulberry silkworms cocoon production in China primarily focuses on wild silk from the Chinese Tussah moth ("Antheraea" spp.). This moth typically feeds on trees (e.g. oaks) and its larvae spin coarser, flatter, yellower filament than the mulberry silk moths.
Caddisfly silk
Trichoptera, or Caddisfly, larvae use silk to hunt and protect themselves in their aquatic environment. Much like silkworms (B. mori) and other Lepidoptera, this silk protein is excreted by specialized silk glands. The silk’s structure is mostly conserved among many different caddisfly species, and can be used to bind debris including rocks, sticks, twigs and shells, as well as to build nets for catching prey. Caddisflies, which spend the majority of their life cycle in the larval stage, need these casings to protect their underbellies and pupate. Caddisfly silk is very strong and durable. Because their silk must be able to bind to a variety of components while completely submerged in water, it is therefore being studied for potential applications as a waterproof adhesive.
Tubifex
Although the "Tubifex" worms are hermaphrodites, the male and female organs become mature at different times; thus self-fertilization is avoided, and cross-fertilization is encouraged. Two mature "Tubifex" worms undergo copulation by joining their ventral and anterior surfaces together with their anterior ends pointing opposite directions. Thus, the spermathecal opening of each worm is nearer to the male apertures of another worm. The penial setae of one worm penetrate into the tissues of other worm and thus the conjugants are held together. At this stage, the sperm of one worm is passed into the spermathecae of the other worm. 
After copulation, they separate and begin to produce egg cases containing eggs, called cocoons. The cocoon is formed around the clitellum as a soft, box-like structure into which the ova and the sperm are deposited. Soon, the "Tubifex" worm withdraws its body from the egg case by its backward wriggling movements.
Assam silk
Muga silk is the product of the silkworm "Antheraea assamensis" endemic to Assam. The larvae of these moths feed on som ("Machilus bombycina") and sualu ("Litsaea polyantha") leaves. The silk produced is known for its glossy, fine texture and durability. It was previously reported that muga silk cannot be dyed or bleached due to "low porosity", but this is incorrect; muga takes dye like any other silk. This silk can be hand washed with its lustre increasing after every wash. Very often the silk outlives its owner.
In 2015, Adarsh Gupta K of Nagaraju's research team at Centre for DNA Fingerprinting and Diagnostics, Hyderabad, India, discovered the complete sequence and the protein structure of muga silk fibroin and published it in "Nature" Scientific Reports
Silkworm (disambiguation)
The silkworm ("Bombyx mori") is the larva or caterpillar of a moth that is very important economically as the producer of silk.
Wheel bug
Females lay eggs at a low elevation on trees, bushes, twigs, and other objects. Secreted glue serves as an adhesive which maintains the cluster formation of the eggs. After the nymphs hatch, the average length of each molt is roughly 18.8 days, though the 5th and final molt prior to the adult stage is the longest. Eggs generally hatch in the beginning of May and finally mature into adults by July. Overall, it takes roughly 94 days for nymphs to reach maturity. However, the phenology of this life cycle varies based upon the climate which the population occupies. For instance, communities in warm climates may not overwinter as eggs.
Bombyx mori
Eggs take about 14 days to hatch into larvae, which eat continuously. They have a preference for white mulberry, having an attraction to the mulberry odorant cis-jasmone. They are not monophagous since they can eat other species of "Morus", as well as some other Moraceae, mostly Osage orange. They are covered with tiny black hairs. When the color of their heads turns darker, it indicates they are about to molt. After molting, the larval phase of the silkworms emerge white, naked, and with little horns on their backs.
Cassina Baraggia
In addition to the cultivation of vines, from the middle of the century the cultivation of mulberry trees had spread enormously in the region, and was planted on the edge of the fields, so as not to supplant other crops. The mulberry trees were used to feed the silk worms, which were given by the owner to the tenant farmers. Mostly women and children worked on the breeding of silk worms. The explosion of silk worm translated as the construction of a textile mill in Baraggia (another being placed in Moncucco), where the first phase of production of silk (reeling) was performed.
Microshift
Hookworms
Silk
Silkworm silk was used as the standard for the denier, a measurement of linear density in fibers. Silkworm silk therefore has a linear density of approximately 1 den, or 1.1 dtex.
Silk emitted by the silkworm consists of two main proteins, sericin and fibroin, fibroin being the structural center of the silk, and serecin being the sticky material surrounding it. Fibroin is made up of the amino acids Gly-Ser-Gly-Ala-Gly-Ala and forms beta pleated sheets. Hydrogen bonds form between chains, and side chains form above and below the plane of the hydrogen bond network.
Silk
RSF is produced by chemically dissolving silkworm cocoons, leaving their molecular structure intact. The silk fibers dissolve into tiny thread-like structures known as microfibrils. The resulting solution is extruded through a small opening, causing the microfibrils to reassemble into a single fiber. The resulting material is reportedly twice as stiff as silk.
Osmia bicornis
During cocoon formation, the larva uses saliva to encompass the fecal material and cell. The anterior part of the cocoon is composed of a domed collar and a central, domed nipple region, and the larva weaves salivary "silk" threads in a circular pattern in this region. The larva also uses its digestive contents to form smears on the cocoon, leading to hardening of the cocoon and a color change to a dark, red-brown. In this stage, in which the organism becomes classified as an imago, the metabolic rate of the imago declines because it must have enough food to survive the winter. Both the imago's body weight and fat body weight decrease.
Stigmella hoheriae
The females lay eggs on the surface of a still growing leaf of their host plant. Larva have been recorded from February to August and are 2–3 mm long and pale transparent green. They mine the leaves of their host plant. The mine consists of blotches, mainly on the lower leaves. The mine is narrow and crosses over itself several times, but rarely passes larger leaf ribs. The frass is deposited in a straight, granular line medially in the mine. The cocoon is spun from dark brown silk (from larvae found on "Hoheria lyalli" and "H. glabrata") οr pale whitish silk (larvae on other "Hoheria" species). It is located amongst the debris at the base of the food plant. Adults are mainly on the wing from August to November. However adult moths have been recorded in February and from July to December indicating there are likely two generations per year.
Eriogaster lanestris
Larvae mature through five stages, called instars, over the course of six to seven weeks. During early larval development (instars 1–3), larvae are small and black in coloration, and during late development (instars 4–5), larvae develop urticarial hairs and red coloration. In their fifth instar, larvae lose many of their social behaviors and colonies disband as individuals prepare for pupation.
"E. lanestris" eggs hatch in April and May, and following their emergence, caterpillars immediately construct tents out of silk at their hatching site, or nearby on the same bush. They live in these tents as colonies of approximately 200 of their full siblings during their development. They continually repair and expand the same structure throughout larval development. The tent consists of layers of silk fibers that form air pockets which serve to insulate the nest and provide resting spaces for caterpillars inside. Tent structures are severely damaged by heavy rains, which cause their silk layers to stick together, removing air pockets. Dried silk also becomes brittle and fragile, making it susceptible to breaking and tearing. Additionally, small eggars’ tents are bright white and not well-concealed, so they are easily located and damaged by predators like birds. Maintaining the integrity of the tent is essential to larval colonies’ survival, and they do not abandon the tent until just before pupation.
Animal fiber
Silk is a "natural" protein fiber, some forms of which can be woven into textiles. The best-known type of silk is obtained from cocoons made by the larvae of the silkworm "Bombyx mori" reared in captivity. Rearing of silks is called sericulture. Degummed fibers from "B. mori" are 5-10 μm in diameter. The shimmering appearance for which silk is prized comes from the fibers' triangular prism-like cross-sectional structure which allows silk cloth to refract incoming light at different angles.
Fibroin
Fibroin is an insoluble protein present in silk created by spiders, the larvae of "Bombyx mori", other moth genera such as "Antheraea", "Cricula", "Samia" and "Gonometa", and numerous other insects. Silk in its raw state consists of two main proteins, sericin and fibroin, with a glue-like layer of sericin coating two singular filaments of fibroin called brins.
The fibroin protein consists of layers of antiparallel beta sheets. Its primary structure mainly consists of the recurrent amino acid sequence (Gly-Ser-Gly-Ala-Gly-Ala). The high glycine (and, to a lesser extent, alanine) content allows for tight packing of the sheets, which contributes to silk's rigid structure and tensile strength. A combination of stiffness and toughness make it a material with applications in several areas, including biomedicine and textile manufacture.
History of silk
Silk was made using various breeds of lepidopterans, both wild and domestic. While wild silks were produced in many countries, there is no doubt that the Chinese were the first to begin production on such a large scale, having the most effective species for silk production, the "Bombyx mandarina" and its domesticated descendent "B. mori". Chinese sources claim the existence of a machine to unwind silkworm cocoons in 1090. The cocoons were placed in a large basin of hot water, the silk would leave the cauldron by tiny guiding rings, and would be wound onto a large spool, thanks to a backwards and forward motion. Little information exists about spinning techniques in use in China. The spinning wheel, in all likelihood moved by hand, was known by the beginning of the Christian era. The first accepted image of a spinning wheel appears in 1210. There is an image of a silk spinning machine powered by a water wheel that dates to 1313.
Thai silk
Thai silk is produced from the cocoons of Thai silkworms. Thailand's silkworm farmers cultivate both types of the domesticated silkworms that produce commercial silk: "Samia ricini", commonly known as the eri silkworm, which produces matte eri silk, and the "Bombyx mori", producer of the better known, glossy mulberry silk. The latter is by far the larger silk producer of the two.
Embioptera
Embiopterans produce a silk thread highly similar to that produced by the much better known silkworm "Bombyx mori". The silk is produced in spherical secretory glands in the tarsi of the embiids enlarged forelimbs, and can be produced by both adults and larvae. Unlike "Bombyx mori" and other silk-producing (and spinning) members of both Lepidoptera and Hymenoptera, which only have one pair of silk glands per individual, some species of embiid are estimated to have up to 300 silk glands: 150 in each forelimb. These glands are linked to 'setae-like cuticular process called a silk ejector', and their exceedingly high numbers allow individuals to spin large amounts of silk very quickly, creating extensive galleries (see image below). The silk web is produced throughout all stages of the embiopteran lifespan, and requires very little energy output.
Silk
Silk is produced by several insects, like silk worms but generally only the silk of moth caterpillars has been used for textile manufacturing. There has been some research into other types of silk, which differ at the molecular level. Silk is mainly produced by the larvae of insects undergoing complete metamorphosis, but some insects such as webspinners and raspy crickets produce silk throughout their lives. Silk production also occurs in Hymenoptera (bees, wasps, and ants), silverfish, mayflies, thrips, leafhoppers, beetles, lacewings, fleas, flies, and midges. Other types of arthropod produce silk, most notably various arachnids such as spiders.
Stigmella cypracma
The cocoon is made of brown silk within the mine. Cocoons with live pupae have been found in May, June, August, September and December.
Thai silk
The production of Thai silk begins with the "Bombyx mori", a small silk worm that comes from the eggs of a silk moth. For their first year, these worms feast on the leaves of mulberry trees before building a cocoon with their spittle.
Agelena consociata
A new colony can be started by a single female spider, a group of immatures or by a group of adults and juveniles. Eggs are laid at times of high humidity and there are a large number of cocoons between November and January.
Ahimsa silk
The process of creating ahimsa silk begins in one of two ways: either the pupa is allowed to hatch and the leftover cocoon is then used to create silk, or the cocoon may be cut open, achieving much the same result but often saving the resultant material from contamination by urine from the hatching moth.
Spider
Their abdomens bear appendages that have been modified into spinnerets that extrude silk from up to six types of glands. Spider webs vary widely in size, shape and the amount of sticky thread used. It now appears that the spiral orb web may be one of the earliest forms, and spiders that produce tangled cobwebs are more abundant and diverse than orb-web spiders. Spider-like arachnids with silk-producing spigots appeared in the Devonian period about , but these animals apparently lacked spinnerets. True spiders have been found in Carboniferous rocks from , and are very similar to the most primitive surviving suborder, the Mesothelae. The main groups of modern spiders, Mygalomorphae and Araneomorphae, first appeared in the Triassic period, before .
Tent caterpillar
Caterpillars grow rapidly and typically complete their larval development in seven to eight weeks. When fully grown, the caterpillars leave the natal tree and seek protected places on the ground or under the eaves of buildings to spin their cocoons. About two weeks later, they emerge as adults. Shortly after eclosing from the cocoon, the female moth secretes a pheromone which draws males to her. Mating typically occurs in the early evening and the mated female, already fully laden with eggs, typically oviposits the full complement later that same evening. The eggs are placed around the circumference of a branch and covered with a frothy material called spumaline. Spumaline is hydrophilic and prevents the eggs from drying out. It also serves as a protective covering which limits the ability of small wasps to parasitize the eggs. Although the male moth may live for a week or more, the female dies soon after laying her eggs. Thus, the whole of the female's adult life may take place in fewer than 24 hours.
Château de Gageac
The mulberry bushes along the road were for rearing Bombyx (silkworm), and were a great success in the 1870s. Bombyx feed on the leaves of the mulberry, whose growth is very rapid. The cocoons were boiled and sent to Lyon, then a silk manufacturing centre, to be unwound, forming embroidery thread of high quality.
Cyrba
The spider spins silk on which to moult. "Cyrba" makes an egg sac by spinning a thick silk sheet on the side of a rock, and then ovipositing the eggs in the center, covering them with another layer of silk. The egg sacs have clusters of white spots. "Cyrba" spiders generally stay with their eggs until they hatch. In a laboratory, they do not spin silk for moulting or resting.
History of silk
She then had the idea to weave some of it, so she kept some for herself. Having observed the life of the silk worm on the recommendation of her husband, the Yellow Emperor, she began to instruct her entourage in the art of raising silk worms, sericulture. From this point, the girl became the goddess of silk in Chinese mythology. Silk eventually left China via the heir of a princess who was promised to a prince of Khotan. This probably occurred in the early 1st century AD. The princess, refusing to go without the fabric that she loved, would finally break the imperial ban on silk-worm exportation.
Animal fiber
The length of the silk fiber depends on how it has been prepared. Since the cocoon is made of one strand, if the cocoon is unwound carefully the fibers can be very long.
Attacus atlas
After reaching a length of about , the caterpillars are ready to pupate. They spin a 7-8 cm long papery cocoon interwoven with desiccated leaves and attach it to a twig using a strand of silk. The adult moths emerge from the cocoon after approximately four weeks depending on environmental factors.
Hemipepsis ustulata
The well-nourished grub begins to spin a delicate framework to support its cocoon.
The "Hemipepsis" cocoon is a brown, silk structure. It is slightly wider at the end from which the wasp will emerge. The inner wall is varnished, but no inner cocoon is seen. Completion takes several hours, and at the end of it, the grub evacuates its alimentary canal; this meconium, or first stool, becomes a hardened mass at the end of the cocoon. The grub is much smaller than it was at the end of feeding because it has expended so much body content on spinning the cocoon and voiding its alimentary canal. The cocoon turns a greasy amber yellow from the original silky gray. The time of hatching is dependent on the season. A cocoon formed early in the summer may hatch the same summer, but a late summer or autumn brood may remain in cocoon form until the following spring or summer. Once the grub reaches the pupal stage, the grub lies extended and quiet. The head capsule splits along the midline, and a glassy, whitish pupa forces its way out of the discarded, shriveling larval skin. The pupa turns creamy yellow, with gray-blue, large compound eyes showing through the thin integument. One can also see the antenna, stubby wing pads, and back spines.
Abacarus hystrix
Cereal rust mite eggs are exceptionally small and are placed in leaf vein grooves by the mite. The eggs usually begin hatching at the beginning of spring (March in the Northern Hemisphere and September in the Southern Hemisphere) and once they have reached the juvenile stage, the mites mature very quickly (16–18 days). Once the mites are at the adult stage they often travel to the lower section of the plant where they feed on young tissues. Mites are always present for the full growing season of the plant, but activity has been seen to decrease as the temperature begins to rise, this is because unlike other mite species the cereal rust mite favors much cooler temperatures.