Column. Vegan Fashion Guide: "Why is Silk a No-Go?"

Silk is soft, light, and warm to the touch. Due to its elegant luster, it was considered a very precious material in ancient China, presented as tribute to emperors and kings. Even today, silk garments are popular for their high absorbency and breathability.

However, are you aware that there are critical views on the ethical issues involved in silkworm rearing, which is essential for silk production? Let's learn about the history of beautiful silk and its manufacturing process, and consider the issues surrounding silk.

What is Silk? The History of its Origin

Silk, also known as "kinu," is a thread-like fiber reeled from the cocoons that silkworms, the larvae of moths, spin before pupating.

Silk production is believed to have begun in China around the 15th century BC, and later spread to Europe and Japan. Although the exact origins are not clear, silk became one of the most valued fibers worldwide, with the East-West trade route traversing Central Asia being named the "Silk Road" in the 19th century.

Silkworms, which hatch in the warm spring, are initially about 3mm in size. They then grow by feeding on mulberry leaves and molt. After several repetitions of feeding and molting, they eventually begin to spin silk from their mouths, gradually forming a cocoon. After about three days, the silkworm stops spinning silk inside the cocoon and molts again to become a pupa. The cocoon formed at this time is boiled in hot water to loosen the sticky threads, and the reeled thread is called raw silk (kiito), which is the raw material for silk.

Afterward, the thin raw silk threads are gathered together to form thick, strong silk that can be used as a raw material for silk products.

Silk and Veganism: The Ethical Issues with Silk

Silkworms are herbivorous insects that feed solely on mulberry leaves. At first glance, they might seem like an ethical and vegan material, but what issues lie beneath the surface?

Killing by Boiling Cocoons

First, there is the problem of the boiling process, known as "sakucho," which is indispensable in reeling raw silk from cocoons.

Cocoons are very delicate, and the threads stick together due to a sticky component, making it difficult to spin them properly by simply pulling the thread that the silkworm has spun. Therefore, boiling the cocoons loosens the bonds between the threads, allowing them to be reeled as one long raw silk thread.

Normally, after pupating inside the cocoon, silkworms would emerge as adult moths. However, in the silk production process, the cocoons are boiled before the silkworms can emerge, resulting in the death of the silkworms inside.

From a vegan perspective, this process is seen as intentionally killing silkworms, making it an unethical material.

Genetically Modified Silkworms

Next, there is the issue of genetically modified silkworms.

Sericulture, which originated in China, developed in various parts of the world. In this process, many silkworms underwent selective breeding, including genetic modification, becoming domesticated insects.

As a result, adult silkworm moths have partially lost their ability to survive in the wild; they may have mouths but cannot eat, or wings but cannot fly.

Some vegans criticize sericulture itself, arguing that this elimination of silkworms' ability to return to nature is artificial.

Other Issues Surrounding Silk

While some people question the history and manufacturing process of silkworms and silk from an animal ethics perspective, others raise concerns from a different viewpoint, considering the environmental impact of fibers and biodiversity.

Silk is inherently difficult to burn and does not produce harmful gases when incinerated, leading to the view that its environmental impact is lower compared to some other fibers.

Regarding the aforementioned issue of genetically modified silkworms, there is also concern that if humans stop sericulture, silkworms might go extinct, as those that have already lost their ability to revert to nature would struggle to survive independently in the natural environment.

New Silks Replacing Conventional Silk

While there are various pros and cons regarding sericulture and silk production, there are also silks produced in more ethical ways compared to conventional silk.

In this article, we will introduce two types: peace silk and wild silk.

Ethical Silk "Peace Silk"

Peace silk is produced with care to avoid boiling live silkworms before they become adult moths. The raw silk is spun after the pupated silkworms have emerged and left their cocoons, ensuring no harm comes to the silkworms.

For example, Ahimsa Silk, produced in India, is one type of peace silk manufactured without killing silkworms.

It takes approximately 10 days for a pupa to emerge. This means that peace silk takes much longer to produce than conventional silk. Furthermore, when silkworms emerge, they break their cocoons to get out, so with the peace silk production method, the raw silk breaks in the process and cannot be spun into long threads.

While peace silk is produced by protecting the lives of silkworms, due to the reasons mentioned above, it is difficult to produce in large quantities at a low cost, and it still faces the challenge of not being widely distributed.

"Wild Silk" Can Also Address Environmental Impact

The term "silk" encompasses not only silk from silkworms raised in domesticated environments ("kasan-shi") but also silk from other cocoon-forming insects ("yasan-shi" or "wild silk").

For example, the Japanese native species, the tensan (yama-mayu), is a type of wild silk. Unlike domesticated silkworms, it grows in a wild environment, making it arguably a more ethical material than domesticated silk. Furthermore, wild silk feeds on plants growing in its native region, which reduces the risk of genetic contamination and is considered more sustainable from an environmental impact perspective.

Besides tensan, various types of wild silk exist worldwide, but it is crucial to note that these are wild insects. Therefore, maintaining ethical production volumes and methods that consider biodiversity is important.

Summary

The issues surrounding silk encompass not only vegan perspectives that prioritize animal ethics but also considerations such as environmental impact and biodiversity, making it impossible to judge right or wrong in a simplistic manner. However, the development of alternative materials like peace silk and wild silk, as introduced in this article, is progressing.

It's important to re-examine the values you hold dear and make proactive product choices!

[References]
Okaya Silk Museum
[Reference Articles]
National Agriculture and Food Research Organization｜Silkworms are amazing insects!
The evolutionary road from wild moth to domestic silkworm
Kaze Travel Agency｜What is the "Silk Road"?
Dainippon Sanshi Kai｜Let's raise silkworms
Wild silk as a new silk material