Worms

THE LIFE CYCLE AND EXPLOITATION OF THE BOMBYX MORI

The silkworms responsible for the vast majority of commercial silk production are Bombyx mori, domesticated and selectively bred from the wild Bombyx mandarina. When a Bombyx mori lays eggs, they usually hatch within 10 to 14 days. However, depending on the farmer's needs, they are often placed in the refrigerator for months, up to a year. Once warmed up, they generally hatch within the same timeframe. Newborns must be fed immediately because they have a voracious appetite and will die very quickly from dehydration and starvation.

Bombyx mori have a preference for white mulberry leaves (their name is actually Latin for "mulberry silkworm"), and mulberry silk is considered the finest and most lustrous. Newborns eat constantly and go through five instars, the term for the developmental stage between molts. Over a period of about 35 days, the Bombyx mori has shed its skin four times, ending up 10,000 times heavier and 30 times longer than at hatching. Once they reach their fifth instar, they enter their pupal stage and wrap themselves in cocoons of pure silk.

The silk itself is secreted by two salivary glands in the larvae's head and consists of two proteins: fibroin, the structural core, and sericin, the "gum" that cements the filaments.

SUFFOCATION AND PRODUCTION

To escape their cocoons, the silkworms, at this stage moths, chew their way out, thereby considerably shortening the length of the silk threads and diminishing their value and the luster of the material produced. To prevent this destruction of raw materials, silk producers will stifle, which means kill, the pupae either by baking them, immersing them in boiling water, or, more rarely, freezing them or piercing them with a needle. This is usually done between two days and two weeks after the start of spinning, before they transform into moths.

Once the pupae are dead, the cocoons are then soaked in water to be more easily unreeled. The chrysalises are subsequently discarded or, in some countries, eaten. If they were allowed to live past their pupal stage, they would emerge from their cocoons as moths, mate, lay eggs, and die naturally after about a week because they can no longer eat and depend entirely on the nutrients they absorbed during their larval stage.

Another way silkworms are used is for the production of what is called silkworm gut, which is mainly used to make fly-fishing leaders. Silkworms are killed by methods such as submersion in a vinegar solution, just before they are about to spin and their silk glands are removed and stretched into strong threads, which look and feel very much like plastic.

SENTIENCE AND SCIENTIFIC DEBATE

As to whether silkworms or insects in general are sentient and capable of feeling pain, studies conducted with morphine demonstrate that insect responses indicate an ability to feel pain, but the scientific community remains in conflict. Silkworms possess a central nervous system and a brain and certainly display nociception (the reaction of sensory receptors provoked by stimuli that threaten the integrity of the organism).

Even if we assume that their death is painless—and we all know what assumptions are—it is still a death, and a premature death induced by humans.

ALTERNATIVES AND "PEACE SILK"

An alternative to this method of silk production has emerged, called "peace silk" or "Ahimsa silk" after the Sanskrit term for non-violence. There are a number of sources and methods under the umbrella of "peace silk," and they are not all very different from the traditional approach. The most idealized version of peace silk is that which is harvested in the wild from the empty cocoons of silk moths.

Eri silk, for its part, is made from the cocoons of Samia ricini, which leave a small hole in their cocoon from which they emerge. This type of silk cannot be processed like Bombyx mori silk and represents a very small portion of the silk market. Ahimsa silk is made from Bombyx mori that have been allowed to undergo their metamorphosis and exit their cocoons before the cocoons are harvested. Peace silks are more expensive and less lustrous than traditionally cultivated silk due to the torn cocoons, and represent only a small fraction of the broader silk industry.

The clarity of actual practices from various peace silk suppliers can be difficult to determine. Silk moth cultivator Michael Cook wrote an article criticizing various peace silk methods, highlighting potential deaths inherent in the next generation of eggs and newborns and the unrealistic idealistic notion of wild-picked empty cocoons. Now, Mr. Cook himself breeds and kills silkworms, so his input on the potential ethical conflicts of peace silk is interesting to say the least. Peace silk producers have refuted and will refute such criticisms, but I think it is important to thoroughly study all so-called "humane" methods of producing animal products and byproducts and to ask whether the use of living beings in any form can be ethical.

CONCLUSION ON EXPLOITATION

Regardless of their treatment, the fact remains that domesticated silkworms are exploited for their silk. They have been selectively bred for the sole purpose of producing as much silk as possible, much like food industry animals that have been bred into deformed absurdities too large to support their own body weight. The adult Bombyx mori cannot even fly. Nor can they eat due to their reduced mouthparts and small heads, a fact often cited as evidence of human manipulation, but this is true of all Saturniidae or giant silk moths.

The fact remains that these are living beings with their own paths, with brains, nerves, and desires.