Which moth produces the strongest natural silk used in commercial silk production?

The domestic silk moth produces the silk used in commercial silk production.

The domestic silk moth, Bombyx mori, has been bred for thousands of years because its larva spins a large, continuous cocoon of silk. People unwind the cocoon into a long filament and combine filaments to make silk thread and fabric. The species is descended from the wild silk moth Bombyx mandarina and is now highly dependent on humans for survival in its domesticated form.

Silkworms are usually fed leaves of the mulberry tree, especially white mulberry. To preserve the continuous filament, commercial processing traditionally kills the pupa inside the cocoon before the adult moth emerges and breaks the thread.

The domestic silk moth is not the same as every insect called a silkworm. Other moth larvae also produce useful silk, but Bombyx mori is the principal species behind traditional sericulture and the historical silk trade.