Silkmoth Caterpillar

Bombyx mori

, Chivilongui Magdalena Colombia

Quick Facts

  • Scientific Name: Bombyx mori
  • Family: Bombycidae
  • Known Nicknames: Silkworm, Mulberry Silkworm
  • Average Length: 5–7.5 cm / 2–3 in
  • Average Weight: 3–5 g / 0.1–0.2 oz
  • Wingspan: N/A
  • Key Feature: Creamy-white segmented body with specialized silk-producing spinnerets below the mouthparts
  • Primary Diet: Herbivore (Monophagous; exclusively Mulberry leaves)
  • Range: Global (Domesticated; originally native to Northern China)
  • Habitat: Mulberry trees and controlled sericulture environments
  • Social Structure: Gregarious
  • Nesting/Breeding: Surface of mulberry leaves
  • Conservation Status: Domesticated (Not Evaluated)
  • Population Trend: Stable

The Silkmoth Caterpillar (*Bombyx mori*), commonly known as the silkworm, is a remarkable domesticated insect that has been prized for millennia for its role in the production of luxurious silk. Characterized by its soft, translucent, cream-colored body and a distinctively large, segmented appearance, this larva is entirely dependent on human care, having lost the ability to survive in the wild. Its most extraordinary feature is its pair of specialized salivary glands, which it uses to spin a single, continuous strand of shimmering raw silk—reaching lengths of up to 900 meters—to construct a protective cocoon for its metamorphosis. These voracious eaters feed exclusively on fresh mulberry leaves, growing rapidly through several molting stages before they begin their intricate weaving process. Beyond its economic significance, the *Bombyx mori* stands as a unique biological marvel, representing one of the few completely domesticated invertebrates in the world.

Habitats & Distribution

This species is entirely domesticated and no longer exists in the wild. Its habitat is exclusively restricted to human-controlled environments, specifically indoor rearing facilities and sericulture farms. Within these settings, they are kept in climate-controlled conditions on large trays where they are provided with a constant supply of their primary food source, the leaves of the white mulberry tree. Originally native to northern China, the distribution of these caterpillars is now global, following the spread of the silk industry. They are found in any region where sericulture is commercially viable, with major populations concentrated in China, India, Uzbekistan, Brazil, and Vietnam. Because the adult moths are flightless and the larvae are unable to survive without human intervention, their range is defined by agricultural locations rather than natural ecosystems.

Behaviours & Reproduction

These larvae are characterized by their voracious appetite, spending their entire juvenile stage consuming mulberry leaves to store energy for metamorphosis. Due to thousands of years of domestication, they are entirely sedentary and lack the survival instincts or defensive behaviors found in wild insects. While they do not possess a complex social structure, they are highly gregarious and can thrive in crowded conditions without showing aggression toward one another. The reproductive phase occurs during the short-lived adult stage, where the flightless moths focus solely on mating. Females release a specific pheromone called bombykol, which males detect using their sensitive, comb-like antennae. After a terrestrial mating dance, the female lays between 300 and 500 eggs. A unique aspect of their reproduction is the ability of the eggs to enter diapause, a state of suspended animation that ensures offspring hatch only when environmental conditions and food availability are optimal.

Diet

The Silkmoth Caterpillar, specifically Bombyx mori, is famously monophagous, subsisting almost exclusively on the leaves of the white mulberry tree (Morus alba). These larvae are voracious eaters, consuming foliage continuously day and night to support their rapid development, which can see them increase their body weight by approximately 10,000 times in just thirty days. An interesting aspect of their feeding behavior is their extreme pickiness; they possess specialized chemoreceptors that are highly tuned to specific chemical compounds found in mulberry leaves, making them reluctant to eat anything else. This specialized diet is essential for the production of liquid silk, as the nutrients from the leaves are converted into the proteins fibroin and sericin within their specialized glands. While they can survive on other mulberry varieties, the white mulberry provides the optimal nutritional profile for producing the finest silk, and in commercial settings, they are sometimes fed a processed artificial diet made from mulberry leaf powder to maintain production throughout the year.

Colors

The *Bombyx mori* caterpillar is typically a pale, creamy white or translucent grey with smooth, hairless skin. It features distinctive dark brown or black crescent-shaped markings on its abdominal segments and small, eye-like spots on its thoracic segments. A small, fleshy horn protrudes from its tail, while its overall muted coloration helps it blend into the pale undersides of mulberry leaves.

Fun Facts

These caterpillars are ultimate eating machines, consuming mulberry leaves so voraciously that they grow 10,000 times their initial weight in just one month. Completely domesticated, they have lost the ability to survive in the wild and rely entirely on humans for food and protection. To build their cocoons, a single larva produces a continuous strand of silk that can stretch nearly 900 meters—roughly the length of nine football fields. Remarkably, these tiny creatures possess over 4,000 individual muscles, which is nearly seven times more than a human, allowing them to move with incredible flexibility as they forage and spin.