The "biblical plague" that devours crops and will become more destructive with climate change

Images of an "invasion" of grbadhoppers in Las Vegas have gone around the world.

The insects were attracted by the brightness of the city and caused a lot of problems at the end of July.

At the same time, a cloud of less mediocre but more disturbing insects fell on Yemen, a country devastated by hunger and civil war.

These were lobsters whose appetite can cause considerable crop damage in more than 60 countries, mainly in Africa, the Middle East and Central Asia.

These events could become more frequent: experts fear that climate change will cause insects to act in a more destructive and unpredictable way.

There is already evidence that the increase in global temperature will have a direct effect on insect metabolism.

A study published in 2018 by US scientists in the journal Science showed that warm weather makes insects more active and more likely to reproduce.

This also makes the creatures generally more hungry, and an adult desert lobster can eat its own weight in a day.

The researchers estimated that the overall damage caused by pests in wheat, rice and maize crops could increase by 10 to 25% per degree of warming.

Most of this damage could occur in temperate regions, where most of these cereals are produced.

"With the exception of the tropics, warmer temperatures will increase insect reproduction rates.There are more insects that eat more," wrote one of the authors of the study. , Curtis Deutsch.

Although lobsters are not the only species to devour crops, they are the most watched by national and international authorities because of their destructive potential.

Efforts over the last four decades have held them back, but serious epidemics have occurred, such as the 2004 infestation in Africa, which caused an estimated US $ 2.5 billion in damage to women. cultures.

It is estimated that the share of damage caused by lobster worldwide is relatively low compared to that of all insects, according to experts, at 0.2%.

But the effect of a swarm in a given place can be devastating.

"Drier conditions in the future in the northern and southern limits of the desert lobster range may produce more favorable habitats for this species and have significant negative effects," said Dr. 39, entomologist Michel Le Coq at the BBC, one of the world's leading experts on lobster.

"The risks in terms of damage to crops, pastures and, ultimately, the food and social security of many poor people in developing countries could be enormous," he warned.

According to the Food and Agriculture Organization of the United Nations (FAO), the most devastating pests, such as desert lobster, could harm the livelihoods of 10% of the population World.

Only a "small" swarm eats every day the same amount of food as about 35,000 people.

Her favorite "snacks" include essential cereals such as rice, corn and wheat.

These creatures are among the oldest enemies of humanity, they even appeared in the Bible and the Koran.

In the ancient world, Roman historian Pliny the Elder said that 800,000 people had died in present-day Libya, Algeria, and Tunisia because of the famine caused by an invasion grbadhoppers.

More recently, in 1958 in Ethiopia, a swarm of lobsters covering more than 1,000 square kilometers destroyed 167,000 tons of grain, enough to feed one million people for a year.

The most hungry insects will affect more the temperate regions, because their metabolism slows down when it is too hot, which is already the case in the tropical regions.

In 2016, experts suspected global warming to play an important role when Argentina was facing its biggest lobster infestation for 60 years.

It is thought that a warmer and wetter winter was at the origin of the phenomenon.

FAO, which coordinates a global monitoring network specific to Desert Locust activities, also warns that climate change could create more favorable conditions for migration and distance travel: adult desert lobsters can fly to the desert. 150 km in a day

"With future warming, swarms could reach areas faster than in the past," said the agency.

Warmer temperatures could also allow insects to fly higher and overcome natural obstacles such as mountains, opening up new migration routes.

"In general, Desert Locust invasions should be more frequent and more severe under the influence of climate change," said Arianne Cease, director of the Global Lobster Initiative, at Arizona State University.

Agricultural regions are the most vulnerable to the ravages of locust swarms.

But food crops are not the only ones at risk: in Pakistan, the authorities have faced an infestation threatening cotton crops, which is responsible for nearly half of the country's exports.