How does the walking stick insect help humans?

Phasmatodea, or walking sticks, are not harmful to humans. They do not bite or sting, and for some, make interesting pets. Many species do secrete chemicals for defense and one tribe in Papua New Guinea often uses the secretions for skin infections. Generally though, walking sticks are neither harmful nor helpful, but have been known to cause deforestation in some areas with high populations. Their feces do provide limited fertilization.