Kenya, Ethiopia and Somalia are being ravaged by the worst locust outbreak in decades
Massive swarms of desert locusts are invading east Africa, ravaging crops, decimating pasture and deepening a food crisis in a region where more than 25 million people are already hungry.
Here's what you should know about desert locusts:
WHAT CAUSES LOCUST SWARMS?
Desert locusts usually form swarms under heavy rains, creating a mass of hungry insects that can cross continents and seas in search of food.
They are found in desert and semi-arid areas across 30 countries - from Mali and Niger in west Africa to India and Pakistan in South Asia - but can also affect neighbouring countries.
HOW BIG IS A SWARM?
Swarms vary from about one square kilometre - which can contain 40 to 80 million locust adults - to several hundred square kilometres.
One swarm sighted in northern Kenya was reportedly 2,400 square km, more than twice the size of Paris or New York.
HOW MUCH CAN A SWARM EAT?
A one square kilometre swarm, containing about 40 million locusts, can eat the same amount of food in one day as about 35,000 people, 20 camels or six elephants.
A swarm the size of Paris eats as much in a day as half the population of France.
HOW FAR CAN LOCUSTS TRAVEL?
They usually fly with the wind and can travel more than 150 km in a day.
CAN YOU EAT DESERT LOCUSTS?
Locusts are edible and a rich source of protein, but experts advise against eating them in east Africa at the moment as they may have been sprayed with pesticides as part of control measures.
While people and birds often eat locusts, they cannot eat enough to significantly reduce large swarms.
ARE LOCUST SWARMS DANGEROUS?
The United Nations says desert locusts are the most dangerous migratory pests in the world because they threaten livelihoods, food security, the environment and economic development.
Desert locusts do not attack people or animals.
IS CLIMATE CHANGE CAUSING BIGGER LOCUST PLAGUES?
Scientists say global warming may be behind the current infestations in east Africa and South Asia.
Warmer seas have brought more cyclones to the Indian Ocean, causing heavy downpours along the Arabian peninsula and the Horn of Africa, creating ideal conditions for locust to breed.
WHICH COUNTRIES HAVE BEEN INVADED NOW?
Locusts crossed the Red Sea from Yemen and started arriving in Somalia and Ethiopia in October. They have since spread to Kenya, Uganda, Tanzania, Eritrea. They could also hit South Sudan in the coming weeks as new swarms form.
WHAT CAN BE DONE TO STOP THE LOCUSTS?
The best way to control desert locusts is by spraying them with pesticides or bio-pesticides from vehicles or the air.
Control by natural predators and parasites so far is limited since locusts can quickly move away from most natural enemies.
Eventually, locust swarms decrease by natural mortality or through migration.
Sources: United Nations Food and Agriculture Organization (UNFAO); United Nations Environment Programme (UNEP).
(Reporting by Nita Bhalla @nitabhalla; Editing by Katy Migiro. The Thomson Reuters Foundation is the charitable arm of Thomson Reuters, and covers humanitarian news, women's and LGBT+ rights, human trafficking, property rights and climate change. Visit news.trust.org)
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