Einstein Science Reporting for Kids
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American Association for the Advancement of Science

Bringing locusts together

A locust is a grasshopper that swarms together with others, and their swarms are often known to devastate farmers' crops with their large appetites. They are fantastic fliers, and can cover about 60 miles of distance in five to eight hours. But one particular kind, the desert locusts, is particularly nasty. They spend much of their lives as harmless, solitary creatures, but at times, they transform into very sociable, swarm-forming insects that can pack themselves together by the billions.

Recently, researchers have found a connection between these dramatic shifts in the behavior of desert locusts to the common brain chemical called serotonin, which every multi-cellular organism on the planet has.

This discovery, that serotonin is involved with the behavioral switch in locusts, reveals a mechanism in desert locusts that begins their transformation from avoiding other locusts to being attracted to other locusts. It may even open the door for new methods of controlling pests everywhere.

Dr. Michael Anstey and a group of colleagues monitored the levels of serotonin in the desert locusts while they triggered both the calm, solitary behavior and also the friendly, sociable behavior with physical stimulation. They observed that the locusts behaving the wildest (in swarm-mode) had approximately three times the amount of serotonin in their systems than the solitary locusts.

This finding uncovers a neurochemical mechanism that links interactions among locusts to large-scale changes in their population structure and the beginning of mass migration. Although this discovery does not provide an immediate pest control solution for these destructive desert locusts, experts agree that the new discovery still has potential for pest control if scientists can find good ways to convert swarming locusts back to their calm, solitary phase, with the neurochemical serotonin.


The related report will be published in the journal Science on January 30, 2009.