Locusts of the order Orthoptera: Their Natural Enemies, Benefits and Harms, and How They Differ from Grasshoppers

Locusts, also known as grasshoppers, are a type of pest belonging to the family Acrididae in the order Orthoptera. There are many species, but the East Asian migratory locust is relatively common in China and highly destructive, capable of causing locust plagues in severe cases. So what do locusts eat to grow up? Who are their natural enemies? And how do they differ from grasshoppers?

What do they eat to grow up?

1. Wild locusts

Locusts have large mouths and well-developed jaws, and feed on plant leaves. They prefer thick, fleshy leaves, such as sweet potato, water spinach, Chinese cabbage and other vegetables, and also readily feed on crops like corn, wheat, sorghum, millet, rice, sorghum and barley, as well as reeds, barnyard grass, cogon grass, dog's tooth grass, needle grass, sea blite and some Artemisia plants.

2. Farmed locusts

Grasshopper farming feed sources are wide-ranging, with the main plants being grasses of the family Poaceae. The best feed is various monocotyledonous and pointed-leaf green grasses, or your own planted ryegrass and Mexican corn grass. If there is not enough grass, you can feed a small amount of bran or chaff-type feed, mixed with water and sprinkled in the shed, but this should only be fed as a last resort.

Are they beneficial or harmful insects?

Locusts are an absolute pest. In the adult stage, they feed mainly on the stems and leaves of green plants. Because they lay large numbers of eggs, once the climate is suitable in the first year, a locust plague may occur the next year, filling the sky and covering the sun in a spectacular sight. Wherever they pass, the green of the fields disappears and there is no harvest at all. Protecting birds can help suppress locust plagues.

Who are their natural enemies?

1. Spiders

Spiders are distributed worldwide except in Antarctica, and mostly feed on insects, other spiders and myriapods. To a spider, a locust that hits its trap is not much different from a fly or mosquito; at most it takes a little more effort to wrap it in a few extra layers.

2. Birds

Birds that eat locusts include the oriental pratincole, white-winged black tern and wren-warbler, with the oriental pratincole being especially notable. Birds that eat locusts need to prey on large numbers of locusts during the chick-rearing stage. Taking the common swallow as an example, a pair of parent birds and a nest of chicks can eat more than 16,200 locusts per month.

3. Frogs

Almost all frogs are natural enemies of locusts. Frogs and locusts live in the same type of ecological environment. Low-lying areas, ponds and ditches where reeds and weeds grow are all good habitats for them, so frogs are the vanguard in limiting the reproduction and spread of locusts. According to statistics, one frog can eliminate more than 10,000 pests in a summer. One rice field frog eats an average of 50 pests per day, with the maximum reaching 266. Even the clumsy toad can prey on nearly 10,000 pests in three summer months. By this reckoning, as long as there is an average of one frog in every 2 sq m of cropland, it is enough to suppress the survival of locust nymphs.

4. Mantises

The mantis, also called the praying mantis, is an invertebrate and a carnivorous insect. It is an important natural enemy of pests of agriculture, forestry, fruit trees and ornamental plants in China, and can prey on more than 40 kinds of pests, such as flies, mosquitoes, locusts, moths and butterflies and their larvae and exposed pupae, crickets and other small insects, as well as large insects such as cicadas, migratory locusts and katydids.

5. Lizards

Lizards, commonly known as four-legged snakes or snake's aunt, are distributed all over the world, mostly in the tropics and subtropics. Their living environments are diverse, mainly terrestrial, but also arboreal, semi-aquatic and burrowing in soil. Most feed on insects, and a few species also eat plants. They mainly prey on locusts in spring and summer.

Differences from grasshoppers:

All insects in the superfamily Acridoidea can be called locusts. The superfamily Acridoidea includes 8 families. What we usually call grasshoppers are mainly locusts in the family Acrididae and locusts of the genus Atractomorpha in the family Pyrgomorphidae. (The taxonomic ranks used above, from largest to smallest, are: superfamily -- family -- genus.) Simply put: locusts cover a larger range, and grasshoppers are some groups within locusts. Neither "locust" nor "grasshopper" is a scientific name; both are common names. However, "grasshopper" is more colloquial and is not used academically, while "locust" is relatively accepted in academic use and clearly refers to insects of the superfamily Acridoidea.