Silk Silk Silk is a natural protein fiber, some forms of which can be woven into textiles. The protein fiber of silk is composed mainly of fibroin and is produced by certain insect larvae to form cocoons. The best-known silk is obtained from the cocoons of the larvae of the mulberry silkworm "Bombyx mori" reared in captivity (sericulture). The shimmering appearance of silk is due to the triangular prism-like structure of the silk fibre, which allows silk cloth to refract incoming light at different angles, thus producing different colors. Silk is produced by several insects, like silk worms but generally only
Bombyx mandarina differ in karyotype from those of inland China. Domestic silkmoths are closer to the latter regarding mtDNA sequence data, and especially lack some genetic apomorphies of the northeastern "B. mandarina". Thus, the initial domestic stock came from inland China. "B. mandarina" is able to hybridize with "B. mori". Both in the wild and in a domesticated environment, females release pheromones and wait for males to be attracted and fly to them. However, "B. mori" males cannot fly. Hybridisation in the wild, therefore, inevitably means breeding between domestic ("B. mori") females and wild ("B. mandarina") males. Hybridization is possible in both