The silkworm on the upper right corner is dead. This is how they look when they first come out of the tiny eggs. He didn't survive...he hadn't gotten any mulberry leaves in a while.

The leaves they're on are mulberry leaves.
Silkworms can eat lettuce and mulberry leaves. However,
when they eat lettuce, they do not obtain their natural colors and cannot produce silk/cocoons and are therefore not able to reproduce. Silkworms must be able to spin a cocoon to go into while they transform to moths to reproduce. While it may be possible if they hide themselves in a corner somewhere, they might be lucky and be able to reproduce but they need a cocoon. You will be able to see one approximately a month or two from now.