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Plants have both constitutive and induced mechanical defenses against herbivores. Constitutive anatomical barriers include trichomes (specialized hairs; see Figure 38.8) and thorns, spines that are specialized for defense. An example of an induced mechanical defense is the production of latex. Some plants, such as Euphorbia species, produce a thick, white aqueous suspension of cellular debris, oils, and resins called latex when they are injured by an *herbivore. Insects trapped by this sticky substance starve to death.