Silkworms eat nectar, fruit juices, tree sap and insects after they break their cocoons and become moths. Moths are nocturnal insects, they are mainly active at night and therefore their food sources are also mainly found at night. Moths feed primarily on nectar, a sweet substance secreted by plants. In addition, moths will also eat some fruit juices and tree sap. Apart from these foods, moths also eat some other insects such as mosquitoes, flies and spiders. These insects are a very important source of nutrients for moths, and they provide the protein and other nutrients that moths need.