What percentage of all insects are known to be phytophagous?

Step-by-step solution

For plants, herbivores are the predators. Nearly 25 percent of all insects are known to be phytophagous (feeding on plant sap and other parts of plants). The problem is particularly severe for plants because, unlike animals, they cannot run away from their predators. Plants therefore have evolved an astonishing variety of morphological and chemical defenses against herbivores. Thorns (Acacia, Cactus) are the most common morphological means of defense. Many plants produce and store chemicals that make the herbivore