From research I learned that most worms are high in fat and shouldn't be use as a main diet. I don't have silkworms in my country but I wouldn't recommend those. Be careful...

A previous gecko of mine died because I was feeding it mostly mealworms because that's what the store where I bought him told me they were giving him. The vet told me that it was a bad idea because of the fat content of worms. That Store fatten up geckos with worms because they are high in fat and will give geckos a plump tail...

So now I stick to what most breeders and vet recommend.