It turns out that locusts produce more serotonin when circumstances force them together and they are stimulated by the sight, smell and touch of many other locusts"
Here we have a solitary and lonely creature, the desert locust. But just give them a little serotonin, and they go and join a gang," observed Malcolm Burrows of the University of Cambridge in England.The brain chemical serotonin has been linked to mood in people. It plays a role in sexual desire, appetite, sleep, memory and learning, too.
"Serotonin profoundly influences how we humans behave and interact, said co-author Swidbert Ott of Cambridge, "so to find that the same chemical in the brain is what causes a normally shy anti-social insect to gang up in huge groups is amazing."Now that they know what causes the swarming behavior, scientists can begin looking for ways to prevent it.