Silkworm

The silkworm is the larval stage of the domesticated moth species Bombyx mori. This species has been economically, culturally and biologically significant throughout history due to its use in silk production. Bombyx mori, known to have been first domesticated in China, is now an organism that can only be sustained by human intervention. The silkworm has become entirely detached from natural life and is reared solely for silk production. In this regard, it is one of the domesticated animal species that has lost its evolutionary independence.

Biological Characteristics and Life Cycle

The silkworm is an insect that undergoes complete metamorphosis. Its life cycle consists of four stages: egg, larva, pupa (cocoon), and adult. Larvae hatched from eggs feed exclusively on mulberry leaves for approximately 25 to 30 days. During this period they molt five times and, after completing their development, begin spinning a cocoon. Cocoon formation takes about three days on average and consists of a single silk filament approximately 1000 meters long. The pupae emerging from the cocoon mature into moths, but domesticated Bombyx mori individuals cannot fly and are unable to perform natural mating behaviors on their own.

The development of the silkworm is highly sensitive to temperature, humidity and feeding conditions. Optimal conditions are maintained at temperatures between 23–28°C and relative humidity between 70–85%. Only the leaves of Morus alba (white mulberry) are suitable for larval feeding. Feeding on other plant species disrupts development and prevents cocoon production. The biological isolation of this species, its low genetic diversity and its reproduction exclusively through artificial breeding have rendered it incapable of surviving in the wild.

During cocoon formation, silkworms secrete a protein called fibroin, which is wrapped by a second protein called sericin. During silk processing, sericin is dissolved and removed using hot water, leaving pure fibroin that is then spun into silk thread. Despite its extremely low micron thickness, the resulting silk is remarkably strong. Silk fiber is known for its high elasticity, luster and moisture-absorbing properties. These unique characteristics of this biopolymer have made it a preferred material in both textile and biomedical applications.

Historical Background and Silk Production

Silkworm rearing is one of the oldest animal husbandry practices in human history. It is documented that the initial domestication occurred in China during the 3rd millennium BCE and that knowledge and techniques were kept as state secrets for centuries. China’s monopolistic position in silk production provided the foundation for numerous economic and diplomatic developments throughout history. In this context, the Silk Road served not only as a commercial route but also as a conduit for cultural and technological exchange.

Silkworm rearing (sericulture) gradually spread from China to India, Korea, Japan and Iran, and later reached Europe during the Byzantine Empire. Today, China and India are the primary producer countries, accounting for the majority of global silk production. Silk rearing also holds economic value in certain regions of Türkiye, Uzbekistan, Brazil and Thailand. Sericulture activities are typically carried out in rural areas, with small-scale, family-based production systems being common.

In traditional sericulture practices, silkworm eggs are stored under natural conditions and larval rearing begins in spring when mulberry trees begin to leaf out. In modern practices, production can occur year-round using temperature- and light-controlled incubators. After cocoons are collected, the pupae are usually immersed in hot water before they develop further, which facilitates the unraveling of the silk filament in a single continuous strand. However, this practice requires boiling the pupae alive and has therefore been the subject of ethical debate.

Silk production is not limited to the textile industry; it is also used in medicine for sutures, tissue engineering and biomaterial manufacturing. Moreover, the biodegradable and biocompatible properties of silk proteins have made them an important material in the development of pharmaceutical delivery systems.

Cultural and Economic Significance

The silkworm is significant not only biologically but also as a socio-economic entity. Historically, silk production directly influenced the technological knowledge and economic structures of societies. For example, in China, silk production shaped not only the rural economy but also the fields of art, diplomacy and engineering. Silk fabrics were used in numerous contexts, from imperial garments to diplomatic gifts. In Japan, silkworm rearing was regarded as one of the key sectors during the Meiji industrialization period.

Today, silkworm rearing is supported in many countries as part of rural development programs. It is recognized as an activity that contributes to social development goals, particularly through its labor-intensive structure that relies heavily on female labor. Additionally, silk production is emerging as an industry with low environmental impact and is gaining importance in terms of sustainability through methods aligned with ecological farming principles.

In art and literature, the silkworm frequently appears as a symbolic figure. Associated with concepts such as patience, productivity and transformation, it is also one of the exemplary cases representing nature-culture interaction. Today, silkworms are exhibited in museums, science centers and botanical gardens for educational purposes and are recognized as a species of interest for the conservation of biological diversity and agricultural heritage.