Plants have evolved many defense mechanisms against insect herbivory in the 350 million years in which they have co-evolved. Such defenses can be broadly classified into two categories: (1) permanent, constitutive defenses, and (2) temporary, inducible defenses.[1] These differ in that constitutive defenses are present before an herbivore attacks, while induced defenses are activated only when attacks occur.[2][3][4] In addition to constitutive defenses, initiation of specific defense responses to herbivory is an important strategy for plant persistence and survival.[1]