By Martin Enserink
Serotonin, the brain chemical involved in depression, anger, and a variety of other human behaviors, turns out to have another surprising role: It transforms desert locusts from solitary, innocuous bugs into swarming, voracious pests that can ravage orchards and fields in a matter of hours. The findings, published in tomorrow’s issue of Science, could point the way to new locust-control methods that don’t rely on insecticides.
Most of the time, the desert locust (Schistocerca gregaria) is a bland, greenish insect that lives an inconspicuous life, shunning other members of its species and flying only by night. But when their densities reach a certain threshold, locusts become gregarious: They seek out one another’s company, start reproducing explosively, and eventually form massive swarms that can move thousands of kilometers beyond their usual habitats and create havoc of biblical proportions. The behavior changes are accompanied by a complete physical makeover, taking several generations, during which the insects first turn pink and eventually black and bright yellow.
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