Photo by Paolo Mazzei

From the eggs of the mulberry moth (Bombyx mori), a moth of the moth family (!), caterpillars that are only 3 mm in size hatch after about 10 days. These are fed several times a day with increasing amounts of fresh mulberry leaves. The animals react very sensitively to external influences, which is why they have to be protected from draughts, temperature fluctuations and noise. Even subtle odors such as perfumes can inhibit their development.

Photo by Paolo Mazzei

After about 30 days and four moults, they have grown to a good 10 cm in length and have increased their weight by a factor of 10,000. Now they start spinning themselves a cocoon. This takes up to five days. Shielded from the environment, the caterpillar metamorphoses into a moth.

Photo by Paolo Mazzei

In the middle of the pupal period, when the pupa is no longer a caterpillar but also no moth, the cocoons are dried with heat, killing the pupae. If the moths hatched, the cocoons would be damaged and the silk thread could no longer be unwound. However, up to 1200 m of the noble thread can be won from a cocoon.

Photo by Paolo Mazzei

The moths selected for breeding live only a few days after hatching without feeding. After mating, the female lays 300 to 500 eggs, barely 2 mm in size. The cycle of life starts all over again.

The cultivation of silk began in China. The oldest silk fabric dates back to around 2750 BC. dated. Legend has it that Xiling, the wife of Emperor Huang Di, was the person who discovered it. She observed the silk moth as it developed in her garden and came up with the idea of ​​having an imperial fabric woven from the fine thread of the cocoon.

Silk production became an important industry in ancient China and the valuable fabrics found their way to the western world along the Silk Road.

The Mongols even used silk in combination with leather and iron elements to make light armor that was difficult for enemy arrows to penetrate.

The knowledge of silk was a strictly and successfully guarded secret of the Chinese Empire for a long time. Silk production only flourished in the Mediterranean region in the Middle Ages, after two monks allegedly managed to smuggle eggs of the silk moth and seeds of the mulberry tree to Byzantium in their hollowed-out walking sticks. Silk metropolises emerged in Spain, Italy and France. Silk was even produced at times in Ticino.

However, a hitherto unknown disease almost completely wiped out European silkworms in the mid-19th century.

With industrialization, the downstream silk industry developed quickly and also gained importance in Switzerland, for example in the regions of Zurich and Basel (trimmings, silk ribbons). Around 1900, the silk industry was one of the most important branches of industry in Switzerland. From the middle of the 20th century, the focus shifted from processing to trading. Since then, the textile industry in Switzerland has been steadily shrinking.

For a few years now, silk has been produced again in very small quantities for the domestic market under the Swiss Silk name.