The Desert Locust

A desert locust is a species of short horned grasshopper in the family of Acrididae. They are native to Africa, and are also be found in Arabia, and western and southern Asia. During some population swarms they can even be found as far north as western and southern Spain, and Russia. During a swarm as many as 60 countries can be affected within an area of 32 million kilometers squared, or about 20% of Earth’s land surface.

Over just a few generations, (they have two to five generations per year) this locust can change its form in response to climate conditions. They can be highly fecund, short winged, and remain in small local areas, during what’s known as a recession. The solitary locusts are typically green as instars, and they tend to match the color of their surrounding vegetation. The hoppers become grey as they age. They can become long winged, migratory, and highly gregarious, this state is called an outbreak. During this gregarious morph, the adults develop black patterning on their backs. In the latter phase they tend to spread to new locations. Within just a few years, locusts in an area can go from being almost unnoticeable, to invading a new location and consuming all of its vegetation and crops. This is what’s known as a locust plague. 

Desert locusts during plague years are incredibly mobile and feed on every kind plant and fodder for livestock. They move at about the speed of wind. They tend to fly with the direction of a prevailing wind, and their numbers in swarm are typically 150 million locusts per kilometer squared. They can cover between 100 and 200 kilometers in a day and fly up to an altitude of about 2,000 meters above sea level. They have been known to travel from Africa across the Atlantic Ocean to the Caribbean in ten days. A small locust swarm of one square kilometer will consume the same amount of food as about 35,000 people. A swarm can contain between 40 and 80 billion locusts per kilometer squared, that’s between 100 and 200,000 tons. Thus, their populations require constant collaborative monitoring, and are extremely hard to control. One to two years of favorable weather and moderate to heavy rains contributes to the risk of a major upsurge and plague. 

In 2020 Somalia declared a state of emergency as the locusts destroyed thousands of hectares of crops and grazing land. These plagues usually follow a period of drought, after which the locusts turn from solitary individual insects to gregariously travelers in bands and swarms. Female locusts deposit egg pods containing up to 100 eggs about ten centimeters below the ground. The eggs hatch according to temperature after two weeks. Their average lifespan is between three and six months. 

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