Grasshoppers are generalist herbivores, feeding on a broad range of plant species rather than specializing. The majority of their diet consists of plant foliage, meaning the answer to whether they eat leaves is yes. As chewing insects, they are significant defoliators throughout their lifecycle, from newly hatched nymphs to fully grown adults. This feeding behavior is central to their ecological role and their impact on cultivated landscapes.
The Primary Diet: Grasses and Leaves
Grasshoppers prefer monocotyledonous plants, such as grasses, corn, wheat, and other grains. However, their diet is not limited to this group; they also consume the leaves of many broadleaf plants, or dicots, including alfalfa, soybeans, and garden vegetables. Their survival is closely tied to the availability of tender, young plant matter, making newly emerged seedlings particularly vulnerable.
The young nymphs are especially destructive to small plants because they require a high-quality, easily digestible diet to fuel their rapid growth through multiple molting stages. When preferred grasses dry out, often during mid-summer droughts, grasshoppers shift their focus to the greener, more succulent leaves of broadleaf crops. This adaptability allows them to maintain their populations by exploiting almost any available green food source.
Beyond the Green: Other Food Sources
While leaves form the bulk of their diet, grasshoppers are opportunistic feeders that consume many other parts of a plant to meet nutritional requirements. They eat flowers, immature seed pods, and stems when foliage is scarce or less palatable. During periods of high population density or drought, they feed directly on ripening grains and the crowns of perennial crops like alfalfa, which severely damages the plant’s ability to recover.
Their diet extends beyond living plant tissues, demonstrating flexibility. Grasshoppers scavenge on dead insects, including the cadavers of other grasshoppers, which provides a necessary protein boost. This opportunistic scavenging, along with the occasional consumption of fungi, supplements their herbivorous diet when typical green food sources become nutritionally poor or unavailable.
How Grasshoppers Consume Plants
Grasshoppers possess specialized chewing mouthparts, known as mandibles, which are adapted for cutting and grinding tough plant fibers. The mandibles are robust jaws that move sideways, not up and down, to shear and crush the food. These mandibles feature sharp, asymmetrical edges that allow for effective incision and mastication of plant tissue.
The feeding process is often described as “margin feeding,” where the insect attacks the edge of a leaf to cut a piece of foliage. Other mouthparts, specifically the paired maxillae, help manipulate and push the cut food into the preoral cavity for grinding. This mechanism results in the characteristic ragged edges and holes observed on damaged leaves, as the grasshopper consumes solid pieces of the plant rather than sucking fluids.
Impact on Gardens and Agriculture
The grasshopper’s habit of consuming entire pieces of foliage makes them destructive pests in agricultural settings. Their feeding leads directly to defoliation, which reduces the plant’s ability to photosynthesize and severely impacts crop yield. High population density can cause devastating losses across entire fields, not only by consumption but also by clipping plant stems and causing seed heads to drop.
While a few grasshoppers in a home garden are harmless, their numbers can quickly escalate into swarms, particularly during warm, dry years that favor rapid egg hatching. For example, a density of just 10 adult two-striped grasshoppers per square yard can defoliate a corn crop. This intense, widespread consumption transforms them into a major economic concern.