Desert locusts are normally solitary individuals who eke out a meager subsistence while avoiding others of their species. But when food sources become abundant, such as after a rain, they transform into ravening packs of billions of insects that can strip a landscape bare.The key to the transformation, researchers said Friday, is the brain chemical serotonin, the chemical that in humans modulates anger, aggression, mood, appetite, sexuality and a host of other behaviors.
Serotonin at Work: On left, a locust is ready to swarm and devastate crops. On right, one is in loner mode. The locusts swarm when contact with one another triples their serotonin levels, British and Australian researchers reported in the journal Science.
It appears from this video that certain aromatic compounds can have a similar effect on human serotonin levels :