What is the primary food source for herbivorous insects?

The primary food source for herbivorous insects is leaves and plants because these insects have evolved to feed exclusively on plant material. Herbivorous insects possess specialized mouthparts designed to extract nutrients from plant tissues. Plants provide a wide array of organic compounds, including carbohydrates, proteins, and other essential nutrients necessary for the growth and development of these insects. By feeding on leaves, stems, roots, and other parts of plants, herbivorous insects support their metabolic processes and reproduction. This dietary reliance on plants differentiates them from other types of insects, which may consume fungi, meat, or detritus.