In Mauritania, sunny with a chance of locusts

By John D. Sutter, CNN

Nouakchott, Mauritania (CNN) --- In this outpost in the Sahara Desert, scientists are working feverishly to add a “Biblical problem” to the weather forecasts:

Locust swarms.

The Desert Locust Center here in the capital of Mauritania, an enormous and sandy West-African country, is employing all kinds of technology -- from “eLocust” computing devices to satellite images and crowdsourced locust reports from desert nomads who carry mobile phones -- to try to predict when and where these bugs may congregate by the billions.

The hope is to be able to predict the swarms like weather events.

    It’s no small task, and one with dire consequences. Locusts -- grasshopper-like insects -- have been decimating crops in Mauritania for at least 3,000 years, contributing to food insecurity and poverty. It’s said that after locusts buzz through an area, the trees become skeletons, devoid of bark, and the ground is left completely bare, munched to the roots.

    “Sometimes they can hide the sky,” said Sidi Ould Ely, a researcher at the center.

    When billions of locusts swarm an area -- tens of millions can occupy a kilometer during a swarm event -- farmers are left without crops and food. Livestock die off, too. In 2004, thousands of people were impacted by a major locust swarm.

    Beida Ould Beilil, a date farmer in northern Mauritania, remembers that event well. The locusts ate the bark off of his trees and covered the sky, "like clouds," he said.

    "Nobody can stop the locusts except god."

    God -- or maybe scientists.

    Forecasting these events could save lives, according to the Desert Locust Center's scientists, who met with CNN in December.

    Field workers use eLocust devices to report on conditions that could favor a locust swarm.

    This desert farmer recalls a day when locusts blotted out the sun.

    Locusts are known to eat the little vegetation Mauritania has, including the bark from trees.

    The locust research group, led by Dr. Mohamed Abdallahi Ould Babah, has amassed what Babah says is the largest database on locusts in the world -- showing when the conditions are right for swarms, or “invasions,” as he says, and where they occur.

    In general, these catastrophic events happen when there has been ample rain in the desert and, consequently, when there is plenty of vegetation to feed on. The center monitors all of this with satellite images. And its army of 150 workers uses eLocust gadgets to instantly upload data about locust sightings from the field.

    Adding to that info, the center has started reaching out to Mauritania’s nomadic people, who roam the desert with herds of goats, cattle and camels -- and, also, lately with mobile phones. The center has given them a free number to call when they see locusts. All of that data helps the center to get a sense of when a swarm may hit.

    There’s still plenty of mystery in the process, however.

    That’s because no one knows for sure exactly why locusts swarm.

    Koutaro Maeno, a Japanese researcher who came to Mauritania to study these insects, says the swarms definitely have something to do with the fact that when desert locusts start to feel crowded, they change shape and color.

    Nice locusts that are not prone to swarming are small and green.

    Evil locusts that are starting to crowd each other -- the scientific term for this group is “gregarious,” but they look far too mean for a conversation over cocktails -- get larger, develop barrel chests and change into terrifying colors of red and black.

    Their black antennae make them look like little devils.

    Other theories about why they swarm include: They panic when their population grows and they run out of food; and, because locusts can be cannibalistic, they may be running from each other in an effort not to get eaten -- or chasing each other for access to a food source.

    That's a theory supported by the work of Iain Couzin, an associate professor at Princeton who visited Mauritania to conduct field research on locusts and their group behavior. Here's how Couzin explained the situation in an interview:

    The locusts are very much like a magnet. The magnetic particles in a magnet tend to align with each other. And when they're all aligned across the magnet, that's what gives it magnetism. So we found a similar mathematical ruleset underlying these locusts. That tells us that this alignment can lead to these devastating swarms, but it didn't tell us why they align. That was a huge surprise. It was a situation where we just discovered it by accident. The locusts were trying to eat each other. When it looks like a cooperative swarm, in reality it's a selfish, cannibalistic horde. Everyone is trying to eat everyone else -- and trying to avoid being eaten. The outcome is you run away from those coming towards you and you run towards those going away from you. And that leads to these tremendous swarms moving across desert environments. There's no food around, anyway. So they're making the best of a pretty bad situation.

    The locust center in Nouakchott has had some success in predicting swarms, using this info and combining it with the data from satellites, eLocust machines and nomadic reports.

    Late last year, for example, Babah said the center identified a potential swarm in advance and treated the area with insecticides to prevent a disaster from occurring.

    In other instances, though, the group has not been so lucky.

    Chalk up some of the difficulties to the fact that the satellite images the group uses are not high-resolution enough to spot actual swarming locusts -- only conditions on the ground that would make a swarm possible.

    Babah said more funding is needed for better-resolution images and more frequent monitoring.

    Scientists from Oxford to Princeton are looking into the issue as well.

    Understanding of swarms will continue to grow, Babah said. Of the center’s massive database of locust data, researchers have analyzed only 5%, he said.