There are a few differences between wild and domesticated silkworms with most having to do with increasing dependence on humans and increasing silk production. As well as modifications for increased production, domesticated silkworms have increased tolerance to living together in large groups as larvae.
Compared to wild silkworms, domesticated silkworms exhibit greater growth rate, cocoon size, and efficiency of digestion. All of these characteristics make these silkworms better producers of silk when compared to wild silkworms. In terms of increasing dependence on humans, adult domesticated silkworms cannot fly and require incubation to gestate and hatch. In addition to being bred to be more efficient, strains of silkworms are cultivated to have resistance to different diseases caused by bacteria and fungi.
Within the last 50 years silkworms have become the equivalent of white mice in genetics research on insects and lepidoptera specifically. This has led to research into genetically altering silkworms to provide new products, like spider-silk hybrid silk and gengineered silk designed to exceed the strength of regular spider-silk.
This BBC documentary outlines the physiology of the silkworm, and sets the stage for the next section, the history and historic impact of silkworms.