AtelierMonpli [Public domain] via Wikimedia Commons
Desert locusts (Schistocerca gregaria) are normally solitary insects, but in crowded conditions, they undergo physical and behavioral changes and become ‘gregarious’, clustering in swarms that can include billions of individuals. These swarms devastate crops over large areas of land, causing economic hardship and affecting the livelihood of as many as one in ten people worldwide. The locusts’ transition from solitary to gregarious is triggered by sensory stimuli: either jostling from or the sight and smell of other locusts nearby. Until recently, however, the mechanism of action of these stimuli was not known. Now, scientists report that an increase in serotonin concentration in a specific region of the locust’s nervous system underlies the behavioral changes that lead to swarming.
Lab Anim. (NY) 38, 72 (2009).
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