What Silkworms Eat
Silkworms consume almost exclusively mulberry leaves. The modern silkworm is completely domesticated, and if not given mulberry leaves by a human, it will wither and die. In total, each silkworm will eat 20 to 25 grams of mulberry leaves during its life—80 percent of which is during a silkworm’s fifth and final stage of development as a larva. By the time it begins to spin its cocoon, the silkworm grows to over 25 times its original size.
Silkworms use the protein and nitrogen in mulberry leaves to create fibroin and sericin, the two proteins that make up their silk cocoons. In modern sericulture, silkworms are sometimes given artificial feed, but they still favor their original staple, mulberry.