Alone, the desert locust is nothing to worry about. It is a solitary creature that stays out of sight munching on plants. But when enough locusts are packed into a small area, they form aggressive swarms that migrate from place to place, consuming all vegetation in their path. The transformation from solitary insect to plaguing swarm happens when conditions force the locusts into close confinement. Along the shores of the Red Sea, the locusts’ winter breeding area, swarms develop when rain falls on the sandy soil to initiate the hatching of locust eggs. If conditions are right—plenty of water and vegetation for food—in the locust breeding areas, a large number of the insects hatch and form swarms.
In March 2007, locust swarms were sighted in the coastal plains along the Red Sea coast in Sudan, Eritrea, Yemen, and Saudi Arabia, said Food and Agriculture Organization (FAO) of the United Nations in its Desert Locust Bulletin. The small swarms were breeding in the lush vegetation left by abundant winter rains. As the vegetation dries, the swarms are likely to move north and inland, warned the FAO.
While locusts are not visible from space, the conditions that allow swarms to develop are easy to spot. This image, created from data collected by the SPOT satellite, shows vegetation conditions. Dark green areas indicate that vegetation was more thick and lush in March 2007 than the average March between 1999 and 2006. Brown areas show where vegetation was more sparse than average. Strips of dark green line the shores of the Red Sea in the same areas where locust swarms were spotted. The image also shows that plants are flourishing inland in Sudan, Eritrea, and Saudi Arabia, where the locusts could migrate. Because such satellite images map the conditions in which locust swarms develop, scientists use them as an early warning to identify areas that should be monitored for locust outbreaks.
- Further Reading:
- Locust!, an Earth Observatory feature article about tracking desert locusts.
- FAO Emergency Center for Locust Operations. (March 2007) Desert Locust Bulletin (pdf) Accessed April 5, 2007.