• Billions of desert locusts in East Africa are swarming at "unprecedented numbers" and pose a huge threat to the region's food insecurity, the UN warns.
  • The swarms are so bad that Somalia declared a national emergency. Ethiopia and Kenya are struggling to maintain the plague, and scientists fear that the insects could spread across Southwest Asia and the Middle East.
  • The swarms are a result of heavy rainfall and cyclones at the end of 2019, which provide ideal environments for rapid breeding.
  • Photos reveal a skin-crawling look at locust plagues and how menacing they can be.
  • For more stories go to www.BusinessInsider.co.za.

Africa's worst locust plague in decades is threatening the continent at an unprecedented scope. And there's no telling just how far the ravenous creatures will travel.

Desert locusts are the most destructive of all locust species - known for their speedy growth and enormous appetites. A swarm containing hundreds of millions of locusts can travel 90 miles (144 kilometres) a day, and each insect can eat its own weight in food.

To put it into perspective, an expert told the Wall Street Journal that "a swarm the size of Manhattan can consume as much food in a day as the population of the New York tri-state area."

The insects have already destroyed hundreds and thousands of acres of crops in East Africa, and the UN is calling for international help to quell the crisis. They fear the numbers could grow 500 times by June and reach 30 different countries.

These photos show just how damaging the desert locust can be.

Desert locusts are the most notorious — and damaging — breed of locust. They're found in around 30 countries throughout Africa, Asia, and the Middle East, and can swarm through one-fifth of the landmass on Earth.

Sources: National Geographic,UN Food and Agriculture Organization

Each locust in a swarm can eat its own weight in food per day. A small portion of an average swarm eats around the same amount as 10 elephants, or 2,500 people.

TONY KARUMBA/AFP via Getty Images

Source: National Geographic,UN Food and Agriculture Organization

A swarm can spread over 460 square miles (1,190 square-kilometres), with 40 million to 80 million locusts per half-square mile (1,2 square kilometres).

Source: National Geographic

Author Laura Ingalls Wilder describes how terrifying a swarm can be in her book "On the Banks of Plum Creek." She wrote that she could feel the insects squishing beneath her feet and hear and the sound of "millions of jaws biting and chewing."

Source: The New York Times

During plague recessions, or "quiet periods," desert locusts typically live in very dry areas of Africa, the Middle East, and South-West Asia that receive fewer than eight inches of rain per year.

Source: UN Food and Agriculture Organization

Locust plagues have been recorded since ancient Egypt, but there's no evidence to suggest plagues occur with any regularity, making them difficult to track.

Source: UN Food and Agriculture Organization

In 1875, the largest locust plague in history turned US skies black, when a swarm 1,800 miles (2,896 kilometres) long and 110 miles (177 kilometres) wide flew over the Midwest. Scientists believe there were trillions of "Rocky Mountain Locusts," a type of insect that's now extinct.

Culture Club/Getty Images

Source: The New York Times

But today's desert locusts are just as havoc-wreaking. According to Dominique Burgeon, an emergency services director at the UN Food and Agriculture Organisation, called the current plague in Africa "an unprecedented situation."

TONY KARUMBA/AFP via Getty Images

Source: Scientific American

During plagues, desert locusts can spread over millions of miles and travel into parts of 60 countries. This affects over 20% of the earth's land surface, and according to the UN, plagues can damage the livelihoods for one-tenth of the world's population.

Source: UN Food and Agriculture Organization

Plagues are defined as periods of one or more years of widespread infestations as a result of good breeding conditions. Throughout the 1900s, there were six recorded plagues. One of them lasted 13 years.

Source: UN Food and Agriculture Organization

Favourable breeding conditions during plagues include moist, sandy soil, and green vegetation. Females can lay up to 158 eggs per egg pod, and are able to reproduce at least three times throughout their life.

Patrick Robert/Sygma/CORBIS/Sygma via Getty Images

Source: UN Food and Agriculture Organization

Eggs hatch in about two weeks and can reach adulthood anywhere between three weeks and nine months.

Source: UN Food and Agriculture Organization

Desert locusts can travel with the wind and easily cover over 90 miles (144 kilometres) per day, with the ability to stay in the air for a long time. Swarms have regularly crossed the Red Sea, which is 186 miles (299 kilometres) wide.

Source: UN Food and Agriculture Organization

In 1954, a locust swarm traveled all the way from northwest Africa to Great Britain.

Sources: National Geographic, UN Food and Agriculture Organization

In 1988, a swarm traveled over 3,000 miles (4828 kilometres) in 10 days from West Africa to the Caribbean.

Sources: National Geographic, UN Food and Agriculture Organization

As desert locusts become more numerous, they change their behaviour to be "gregarious,"and act as a part of a larger group. During this process their colour changes from brown (solitary) to yellow and pink (gregarious).

Source: UN Food and Agriculture Organization

But that doesn't mean locusts are particularly friendly toward one another. They actually become cannibalistic during swarms, and insects that don't move with the flow of the group become easy targets for killing.

Source: World Economic Forum, Max-Planck-Gesellschaft

Locusts typically have a lifespan of about three to five months, depending on weather and ecological conditions. Since desert locusts breed so quickly, a plague can last longer than a decade.

Source: UN Food and Agriculture Organization

Though swarms can look menacing, desert locusts do not outwardly attack people or animals, and there is no evidence to suggest they carry diseases.

Source: UN Food and Agriculture Organization

During locust plagues, pesticides are often sprayed from vehicles and small planes. But researchers have turned to non-chemical methods such as changing farming techniques, and focusing on pathogen and insect growth regulators instead.

Sources: NPR, UN Food and Agriculture Organization

But fighting locusts is an expensive battle. From 2003-2005, $450 million was spent to stop a desert locust plague in Africa that resulted in $2.5 billion worth of crop damage.

Source: Arizona State University

The current locust plague in East Africa is thought to have originated in Yemen, traveling over the Red Sea to Somalia, Ethiopia, and Kenya.

Source: BBC

Unusual periods of heavy rainfall in 2019 created an ideal environment for the insects to breed, according to the UN. Climate scientists blame this on rapidly warming oceans, and as swarms continue to grow, they fear the locusts will soon enter South Sudan and Uganda.

Sources: BBC, Wall Street Journal, UN News, New York Post

Keith Cressman, senior locust forecasting officer with the FOA, told Wired that "A locust plague is much like a wildfire...If you can find it when it's just a tiny campfire, and you can put it out, you're good. No problem." But if not, the swarm will only stop growing when it runs out of food.

Source: Wired

This has been the largest outbreak of desert locusts in Somalia and Ethiopia in 25 years. In Kenya, a plague of this scope hasn't been seen in 70 years.

Source: UN News

The UN estimates that 24 million people are already facing food shortages from weather, general food insecurity, and locust invasions. In Ethiopia, the UN warned that eight million people may need food aid from locust crop attacks.

Source: Wall Street Journal

On Sunday, Somalia became the first country to declare the current locust plague a national emergency, saying that the infestation "poses a major threat to Somalia's fragile food security situation."

Source: Al Jazeera

The UN is currently seeking $76 million (R1.1 billion) from international donors in order to "urgently support both pest control and livelihood protection operations in the three most affected countries."

TONY KARUMBA/AFP via Getty Images

Source: UN News, Business Insider

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