Tel Aviv University researchers have uncovered why locusts form destructive swarms. Known as the eighth of ten plagues that hit Egypt when the Israelites were enslaved in the book of Exodus, swarms of locusts have destroyed crops and caused famines. In search of the answer to what causes the normally harmless and solitary insects to radically change their behavior and form huge migratory swarms, the researchers found that the bacterial composition in the intestine of a locust, or the microbiome, changes drastically when the host insect joins a larger group.
Bacteria called Weissella, which are almost completely absent in the microbiome of loner locusts, become dominant in the “convivial phase” of the insect when it raves with others, according to the study. With the help of a specially developed mathematical model, the researchers followed the changes in the Weissella bacteria and found that the bacteria can spread through swarming and infect a large number of locusts – a clear evolutionary advantage for the bacteria.
“Our results do not clearly prove that the Weissella bacteria are responsible for the swarming and migration of the locusts. However, the results most likely indicate that the bacteria play an important role in triggering this behavior – a new hypothesis that has never been established before,” explained Prof. Amir Ayali, who led the study.
According to Ayali, the study could have a significant impact on “countless people, animals and plants around the world” who are still threatened by locust outbreaks. “We hope that these findings will drive the development of new means of combating locust plagues.”
This article was adapted from Katharina Hoeftmann.
