
Some humans must take medicine with seratonin in it every day of their lives to control their mood. New research now shows that another life form on the planet is dramatically affected by the chemical seratonin.
The new research published in this past Friday's edition of the journal "Science" discusses this phenomenon. According to an article in USA Today:
"A chemical that affects people's moods also can transform easygoing desert locusts into terrifying swarms that ravage the countryside, scientists report. "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.
Under certain conditions, locusts triple the amount of serotonin in their systems, changing the insects from loners to pack animals, Burrows and his co-authors report in Friday's edition of the journal Science.
These packs can be devastating. They affect 20% of the Earth's land. Last year a swarm nearly four miles long plagued Australia. They also occur in Africa and Asia and have affected the western U.S.
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."
Researchers led by Michael L. Anstey of Oxford were studying the changes in locust behavior and tested them for a variety of chemicals. The only change they found was that when the insects were swarming, they had about three times more serotonin in their systems than when they were living as solitary creatures.
So the scientists took some solitary locusts and injected serotonin into them. Sure enough they changed in appearance and flocked together.
The Dr. Jekyll to Mr. Hyde transformation took only a few hours.
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. This can happen, for example, when drought reduces their food supply and causes locusts to gather at a few remaining sources of food.
Indeed, the scientists found that tickling the insects' back legs for a couple hours could induce the locusts to make more serotonin.
Once researchers determined that serotonin causes the change, they gave locusts drugs that blocked serotonin and then exposed them to situations that normally cause swarming. But the change didn't occur.
"To actually be able to stop it from happening, that was very exciting," Anstey said.
Now the question is how to target locusts without affecting humans or other animals.
Source:
http://www.usatoday.com/tech/science/2009-01-29-locust-swarm_N.htm