The desert locust is a type of grasshopper. Like other grasshoppers, they are normally solitary and relatively harmless plant eaters. But, under certain conditions, when drought is followed by rapid vegetation growth, a striking transformation takes place in their brains, bodies, and behavior.
Locusts gather into huge, ravenously hungry migratory swarms. The swarms strip all vegetation in their path, including human food crops. Plagues of locusts have been a threat to agriculture since before Biblical times, and continue to threaten the food supplies of millions of people today.
In the high densities of the swarm, locusts sometimes even eat each other. Some researchers have argued that this cannibalism, and the need to avoid it, may be an important factor in the behavior of locust swarms. Locust cannibalism is interesting to biologists who want to understand animal behavior, and want to find new ways to protect food crops from being eaten by locust swarms.
In 2022 an international team of biologists reported their discovery that locusts can manufacture and secrete a particular chemical that can protect them from cannibalism by other locusts in dense swarms. This type of substance is a pheromone. Pheromones are chemicals that an organism secretes that trigger a social response in other members of the same species. In this case, that response is to prevent cannibalism.
The discovery might offer farmers a new weapon against locust swarms. Possibly, something similar to the pheromone could be sprayed on crops to protect them, or maybe researchers could find a way to block the effects of the pheromone, causing members of the swarm to turn their ravenous hunger on one another.