Desert Locust

Quick Take

• A desert locust looks completely harmless on its own, yet one specific trigger transforms it into something unrecognizable. See the transformation →
• Swarms have defeated every human attempt to stop them, so what actually gives affected regions their best chance? Explore control challenges →
• No crop on Earth has proven unappealing to this insect, which is what makes controlling a swarm nearly impossible. Discover what locusts eat →
• A desert locust can reach sexual maturity shockingly fast, and that speed is exactly what makes swarms so hard to eliminate. See the rapid life cycle →

The desert locust has lived in the arid parts of the world for as long as humans can remember. These hardy insects consume vegetation equal to their body weight on a daily basis. When in solitary mode, desert locusts look like harmless grasshoppers. But when they start to swarm, these locusts can become a destructive force capable of causing major economic damage to any society.

4 Incredible Desert Locust Facts

• Desert locusts can fly at a speed of 21 miles per hour. This allows swarms to travel over 100 miles in a single day.
• A large swarm of desert locusts can contain as many as 150 million individuals per square kilometre, with swarms sometimes covering 150 square kilometres or more.
• A single locust needs to eat its weight in vegetation every day. 2 grams might not seem like a lot, but if a large swarm comes by, it can decimate an entire field of grain in a matter of hours.
• Desert locusts change color as they gather in numbers. Neutral-colored locusts are in solitary mode, but bright yellow locusts have gone gregarious and are ready to swarm.

Classification and Scientific Name

The scientific name for the desert locust is Schistocerca gregaria. Members of the genus Schistocerca are commonly known as ‘bird grasshoppers’ because they are strong fliers, and the genus often includes grasshoppers. Meanwhile, “gregaria” refers to the herd or swarm-like behavior that locusts are known for. There are more than 30 subspecies of the desert locust.

Desert locusts belong to the Insecta class and are part of the Acrididae family. Because of this, one of the most common names for locusts is acridid. Acridids are a subspecies of the grasshopper, and European texts typically differentiate between the two. In America, both words can be used fairly interchangeably to describe both swarming and non-swarming members of this family.

Appearance and Behavior

Desert locusts are large insects that grow to be roughly 8 centimeters in length. They have an appearance similar to grasshoppers; major features include a hard carapace, two extremely visible back legs, four front legs that look like arms, and large translucent wings that are tucked against the sides of the body until the insect is in flight.

One of the most interesting features of the desert locust is that it can change form and color across its lifespan. If population numbers are low, desert locusts will develop as solitary members of the species. Solitary locusts have muted colors and a slightly smaller size. They are significantly more passive, eat less, and do not typically engage with other locusts.

However, if population numbers are high and resources are low, solitary desert locusts will start to transform into gregarious members of the species. A solitary locust can go gregarious within hours, although it may take a few days for the actual physical changes to take effect. Gregarious locusts are pink or red when immature and bright yellow when mature, often with black markings. If a locust nymph hatches during a gregarious period, it will be pink instead of grey.

Gregarious locusts are more active, may attack other locusts, and consume massive quantities of food in an attempt to compete for resources. Gregarious locust swarms are responsible for major crop loss throughout Africa, the Middle East, and any other areas where these insects are present.

Once a swarm becomes active, it travels rapidly across the continent, landing in areas and consuming crops until the vegetation is gone and the swarm moves on. Most locust swarms end after about a year when all available food has run out, and the bugs are no longer able to repopulate nearly as quickly.

Whether or not they are swarming, locust migration tends to be downwind from the area where they were hatched. Adult swarms fly and disperse during the daytime, roosting densely on plants at night, which is when control operations are typically conducted. However, researchers have noticed that locust migration follows the seasonal rains that are common in their natural habitat. In general, these insects will travel to areas where there has been recent rainfall, meaning that there will be ample vegetation and plenty of moist soil where the locusts can lay their eggs.

Although a locust is sometimes confused with a cicada, there are marked differences between these two types of insects.

Habitat

Desert locusts inhabit deserts and dry grasslands. This particular species of locust primarily lives in Northern Africa, but swarms can also be found throughout the Middle East and some parts of Asia.

When they are in solitary mode, desert locusts can typically be found hiding in bushes, trees, fields, and anywhere else with a sufficient amount of edible vegetation. When a drought occurs, locusts will gather together onto any remaining patches of vegetation. This triggers the gregarious mode that leads to swarming, migration, and major crop losses in the local area.

Diet

Desert locusts are herbivorous insects that can eat nearly any form of vegetation. This ability to eat multiple types of food is referred to as polyphagy. A desert locust’s typical daily consumption might include leaves, bark, seeds, grass, flowers, and of course, crops from nearby farms.

So far, no crops have been found that are unappealing to locusts. Food crops like wheat, barley, rice, and corn are just as susceptible as for-profit crops like cotton and tobacco. If locusts swarm in your area, you can expect them to consume every bit of visible vegetation as far as the eye can see. This effect is so devastating that many people refer to locust occurrences as a “plague.”

If you happen to capture a locust, you should be able to feed it on any grains or edible plant matter that you have on hand. Locusts need to consume the equivalent of their body weight every day, which comes to about 2 grams. Whether it’s a handful of oats or some fresh timothy hay, your locust will probably spend the day munching happily on whatever you feed it.

Predators and Threats

Desert locusts are an incredibly hardy species and are listed as being of least concern. In fact, this species is so tenacious that many countries have tried and failed to exterminate it. Some researchers suspect that as global warming increases, conditions will get even more favorable for the desert locust, causing them to become a major threat to sustainable food production.

With that said, desert locusts do have natural predators. Reptiles, birds, wasps, and other creatures that regularly feed on insects consider a single locust to be an excellent meal. Because locusts lay pods of 10–140 eggs at a time and can take several weeks to months to mature, they can sustain population levels even if they are being actively hunted in an area.

The biggest current threat to the desert locust is the use of pesticides on crops in their native habitats. Because locusts can eat any form of vegetation, this does not usually reduce their population numbers by a significant amount. Locust control is very difficult, and affected regions typically rely on a combination of predictive data and early warning systems to help protect their crops.

Reproduction, Babies, and Lifespan

One of the factors that makes locusts so tenacious is their incredibly rapid life cycle. A locust can be sexually mature within a month after its egg was laid, meaning that swarms can repopulate at incredible rates as long as food resources are available.

Locusts have three noticeable stages of development. First, the female locust lays a clutch of around 100 eggs in a patch of moist sand or dirt. These eggs are buried slightly under the surface and will not hatch if the area is too dry or cold. Locust incubation takes about 2 weeks, but eggs may hatch later if the weather is not warm enough.

Once hatched, a baby locust is referred to as a nymph or a hopper. Locust nymphs look much like adults, but their wings have not grown in. Young hoppers are covered in hardened beige or pink carapaces. As the insect gets older, it will molt its carapace up to 5 times. The locust is soft and vulnerable immediately after molting, and it can take a few days for the new carapace to completely harden.

A locust’s wings start to grow in after it molts for the fifth time. At this point in its life cycle, however, the locust is not yet ready to mate. Sexual maturation can take as little as 2 weeks or as long as 6 months, depending on weather conditions and the presence of other locusts.

Much like other species, desert locusts mate in pairs. After mating, females retreat to lay their eggs near the egg pods of other females. Desert locusts are not known to attend to their young after hatching, although it is not unusual for bands of hoppers to rejoin the adult swarm.

A desert locust’s life cycle typically lasts anywhere from 3 months to 1 year. Locusts tend to molt and grow as they get older, so you can generally guess the age of the insect by how large it is. Even if they find enough food and avoid predators, it’s very rare for locusts to live through their first cold season.

Population

Because desert locusts are so numerous, their population is nearly impossible to track. A single swarm could have as many as 80 million individual members at one time, and swarms are located all across Africa, the Middle East, and Asia. Desert locusts are considered to be of least concern, so researchers are not currently focused on tracking actual population data.