Jun 25

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Mali Menace

A Continuation of our Survey of the World – the Natural World


The Arab Spring has given way to the summer of the locusts in North Africa.  Political turmoil in Algeria and the overthrow of Gadafi in Libya have played havoc with normal operations in those countries.  The manpower, materials, and equipment annually reserved for locust control have not been utilized the past 2 tumultuous years, giving rise to an outbreak of locusts in the neighboring countries of Mali, Mauritania, and Niger.  Recently, efforts have been made to combat the impending menace, but it may be too little too late.  Countries like Mali are already suffering from civil war and man-made famine; swarms of locusts could put them over the edge.

A full-fledged locust swarm has hundreds of millions of members and weighs several tons.  It can eat its weight in vegetation every day and can span hundreds of square miles.  If the winds are right, large swarms can escape the boundaries of Africa, even affecting southern European countries like Italy, Spain and Portugal.  The most recent bad outbreak occurred in 2004, from Egypt to Morroco to Portugal.  The popular vacation spot of the Canary Islands, about 60 miles west of Africa, was also inundated.

The most fascinating aspect of locust swarms is not their sheer mass, but how they mass in the first place.  By itself, the locust is really no different than the average large grasshopper that you would find in your backyard.  They are, by nature, solitary creatures.  In northern Africa and other parts of the world, shortages of food and water concentrate locusts in small areas where food and water are still available.  As the space becomes tighter, the locusts bump into one another, and the bumping releases hormones which actually change the color and size of the locusts.  Within several weeks, a calm area with drab colored grasshoppers turns into a seething mass of brightly colored locusts, ready to swarm.  The locusts crawl at first, but, after several moltings, are ready to fly.  And the rest is history.

Different kinds of locusts turn different colors when they are ready to swarm.  The red locust of Madagascar was studied by the Center for International Copperation in Agronomic Research:

The team studied the colour of more than 1,000 red locusts in southwestern Madagascar. They found that a slight black spot appears on the femur at the first sign of gregarisation (when their density rises to ten hoppers per square metre). Once there are 30 hoppers per square metre, the head turns a reddish-orange colour and the first segment of the insect turns yellow.

By the time there are more than 100 hoppers per square metre, the entire body has turned bright orange, the yellow colour of the first thoracic segment is more yellow and the black patches are darker.

Scientists hope that, by noticing color changes, they can anticipate and deal with future outbreaks before they get to an unmanageable size.  Incidentally, the locust swarms that were once famous across the plains of the United States have not been seen in over 100 years.  Scientists theorize that the breeding grounds of the locust were literally “plowed under” by developing agriculture, leading to the species’ extinction.

Map of the 2004 North African Outbreak.

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