Locust

Quick Take

• Locusts aren't actually a separate species, and what makes them locusts is stranger than you'd think. Locusts vs. grasshoppers →
• The largest locust swarm ever recorded went extinct just 25 years later, though no one fully understands why. The record-breaking 1875 swarm →
• A fungus ultimately did what pesticide planes couldn't, and the story of how it works is deeply unsettling. Biological control methods →
• Locusts have plagued humanity for millennia, yet humans found a surprisingly intimate way to fight back. Humans fighting back →

Locusts are insects that are known for their swarming behavior, which occurs when environmental conditions are right. Locust plagues have affected crops and farmland since biblical times, attacking any growing green vegetation in their path.

Colloquially, the words “locust” and “locusts” refer to different creatures depending on where in the world you are. Sometimes, locust may also refer to the cicada, a different species of bug that emerges from the ground and is known for making loud sounds from the trees.

5 Incredible Locust Facts

• These insects are some of the oldest bugs, being relatively unchanged since the Triassic era.
• Migratory locusts have the largest range of any locust or grasshopper species.
• Swarms are nearly impossible to wipe out once they begin.
• The word locust means different things in different parts of the world.
• These insects have plagued humans for thousands of years, destroying large amounts of crops.

Species, Types, and Scientific Name

Locusts belong to the family Acrididae. All locusts belong to Acrididae, but not every bug in the family Acrididae is considered to be a locust.

There are 21 species found worldwide. The major species are:

• Desert Locust (Schistocerca gregaria)
• Migratory Locust (Locusta migratoria)
• Brown Locust (Locustana pardalina)
• Red Locust (Nomadacris septemfasciata)
• Australian Plague Locust (Chortoicetes terminifera)
• Rocky Mountain Locust (Melanoplus spretus — now extinct)

Historical records tell about plagues of locusts that devastated crops thousands of years ago. The ancient Egyptians, the Chinese, and the Bible all have references to them.

Locust vs. Grasshopper

Locusts are not a particular species. They are, in fact, a subset of grasshoppers that develop swarming behavior and gregarious growth when environmental conditions are right. Grasshoppers do not decimate crops and plague farmers the way locust swarms do. They also cannot fly as far as locusts do.

Locust vs. Cicada

Cicadas and locusts are not similar species. Cicadas suck sap from trees and are known to come out of the ground and sing. They also leave their shed shells all over the trunks of trees. Locusts do not exhibit the same burrowing behavior, and they tend to feed in large swarms on crops and other vegetation.

Appearance

These insects typically range from about 1.25 to 3 inches in length and have green or dusty brown exoskeletons. They have long back legs used for jumping and hopping, and they can rub the legs together to create sounds.

There are three stages in the locust life cycle: eggs, nymphs or hoppers, and adults. When they are in the nymph stage, the insect may experience elevated serotonin levels, triggering their gregarious phase. This phase happens when the rain returns after a long dry spell. Then, nymphs and adults change in color, often becoming darker colored with bright markings. This is when the locusts begin to swarm and attack crops, fields, and any area with fresh vegetation.

In this phase, locusts also begin to mature and reproduce more quickly. Their brains increase in size, and they develop more endurance so they can travel farther as a swarm.

The biggest swarm ever recorded was a swarm of Rocky Mountain Locusts in 1875 that is thought to have contained somewhere between 3.5 trillion and 12.5 trillion insects. Surprisingly, the Rocky Mountain Locust went extinct just 25 years later.

Habitat

These insects are found on nearly every continent in the world except for Antarctica and North America. The Rocky Mountain Locust was among the few locust species found in North America, and the last living specimen was recorded in 1902.

Their habitats include fields, wetlands, sparse woodlands, and places where crops are grown or domestic animals are kept. They prefer open, sunny areas with many types of grass and flowers.

Diet

Locusts have been known to swarm in large groups consisting of billions of insects. These swarms attack vegetation and farmland, resulting in human starvation and costly damage to the fields. These insects prefer to eat soft foliage, such as leaves and grasses. Different species will have different diets and different preferences as to which plants they like to consume.

When food is scarce, locusts will sometimes forage on dead grasshoppers, or even target weaker members of their own species.

While they do swarm and devastate crops, these insects play a huge role in stimulating plant growth in their habitats. Nymphs have a larger appetite than adults.

Prevention

In ancient times, people were unable to do much to protect their crops from a swarm of these insects. They were a serious threat and were rightly feared by the people of ancient times.

Modern solutions for these insects once involved massive amounts of pesticides to protect crops. These pesticides were sprayed over the fields using small planes.

In 1997, however, a safer method was found to control massive swarms. A biological pesticide was created that killed insects via fungal growth. It spread from insect to insect, ultimately killing the swarm. The ideal control methods are those that do not greatly affect the environment.

Although they could do little to control locust plagues, humans have been consuming these insects for many millennia. The Torah permits the consumption of certain species, and eating these insects is considered halal. They can be fried or smoked and are considered a delicacy in some cultures.