. The plant is an annual so will die off in the winter, but will reseed itself enthusiastically if you let it.
To answer your question, no i don't recall I having seen any insects on it, but sure there must be, or it wouldn't be so successful in its reproduction. maybe its visitors are so tiny that they easily escape the attention. I don't have it in my mainly shady and enclosed town garden, but I meet it often on rocky and sandy wastelands and along side paths in town.