Grasshoppers, belonging to the suborder Caelifera, are ubiquitous insects found across every continent except Antarctica. They are primary consumers, feeding directly on plants and positioning them centrally in terrestrial food webs. Their abundance and high protein content make them a staple diet for a diverse array of predators, linking the energy stored in vegetation to higher trophic levels.
Vertebrate Hunters of Grasshoppers
Many easily observed grasshopper hunters are vertebrates that rely on the insects for nutrition. Birds are particularly effective predators, with over 200 species known to include grasshoppers in their diet. Raptors like kestrels and Swainson’s hawks consume large numbers, sometimes gathering in flocks to feed on dense outbreaks. Smaller birds, such as meadowlarks, bluebirds, and various fowl like chickens and turkeys, also forage actively in fields and grasslands.
Amphibians and reptiles are significant consumers, often sharing the same moist or grassy habitats. Frogs and toads are ambush predators that use their long, sticky tongues to readily consume the insects whole. Lizards, including species like the bearded dragon, and various types of snakes also incorporate grasshoppers into their diets.
Mammals of various sizes hunt grasshoppers, often opportunistically. Small mammals, such as shrews and mice, are adept at catching them on the ground; the northern grasshopper mouse specifically targets them. Larger carnivores and omnivores, including raccoons, skunks, red foxes, and coyotes, consume grasshoppers when they are plentiful.
Insect and Arachnid Predators
A sophisticated network of smaller invertebrates and pathogens actively preys on grasshoppers across all life stages. Predatory insects like the praying mantis are generalist carnivores that capture adult grasshoppers with their spiny forelegs. Robber flies are specialized hunters, using a powerful proboscis to pierce the insect’s body and inject enzymes that dissolve the internal tissues for consumption.
Egg Predators
Intense predation occurs at the egg stage, when grasshoppers deposit their eggs in underground pods. The larvae of blister beetles and bee flies, as well as adult ground beetles and common field crickets, actively seek out and destroy these egg pods. In localized areas, these predators can destroy up to 80 percent of the grasshopper’s future generation.
Parasitoids and Pathogens
Grasshoppers are also threatened by parasitoids, which use the host to rear their young. Parasitic wasps, such as those in the genus Scelio, target the eggs. Flies, including flesh flies and tachinid flies, lay their eggs directly on the nymph or adult. The resulting larvae burrow inside, consuming the host and causing its death when they emerge to pupate. Grasshoppers are also susceptible to fungal pathogens like Entomophaga grylli, which can cause mass mortality and leave the dead insects rigidly attached to plants.
How Grasshoppers Avoid Being Eaten
Grasshoppers have evolved a range of defensive strategies to cope with relentless predatory pressure. The most common defense is crypsis, or camouflage, where their coloration and body patterns allow them to blend seamlessly with the surrounding vegetation or soil. This adaptation is highly effective at preventing detection by visual hunters like birds and lizards.
When camouflage fails, grasshoppers rely on their powerful hind legs for rapid escape, launching themselves into a vigorous jump. Adults can follow this leap with a short, erratic flight, sometimes employing flash coloration of brightly colored hindwings to startle or confuse a pursuing predator. Some species, like the Carolina grasshopper, utilize an unpredictable flight pattern that makes them difficult for avian predators to track.
A more aggressive defense mechanism involves chemical deterrence, such as the regurgitation of a noxious, brown fluid when the insect is handled or attacked. This fluid is distasteful to many predators. Certain species, like the large lubber grasshoppers, sequester toxins from their host plants and advertise this defense with warning coloration (aposematism), making them highly conspicuous.
The Ecological Importance of Grasshopper Predation
The constant predation on grasshoppers represents a significant ecological pressure that maintains the balance of many grassland and rangeland ecosystems. Natural enemies are a major stabilizing force in grasshopper populations, often preventing the insects from reaching densities that result in destructive outbreaks, such as locust swarms. This control is particularly important in agricultural settings where massive swarms can cause devastating damage to crops and forage.
Grasshoppers are a critical conduit for energy flow, transferring the energy and nutrients from primary producers (plants) to higher trophic levels. When a grasshopper consumes plant matter, it converts that energy into biomass that is then available to its predators. Furthermore, the fecal pellets produced by grasshoppers break down faster than natural plant decay, speeding up the cycling of nutrients back into the soil and enriching the ecosystem.