Animal behaviour: Pheromone turns locusts into a swarm enemy

The pheromone that causes locusts to swarm is revealed in a study published in this week’s Nature. The discovery might aid the development of new methods to control locust outbreaks.

As the most widely distributed and one of the most dangerous locust species, the migratory locust (Locustia migratoria) represents a serious threat to agriculture worldwide. In this study, Le Kang and colleagues identify a small organic compound called 4-vinylanisole (4VA) that is released by gregarious migratory locusts. The molecule acts as a powerful attractant to migratory locusts of all ages and both sexes, and if four or five solitary locusts are housed together, they too begin to produce and emit the pheromone. It also attracts locusts in the field.

The pheromone is detected by specific sensory cells, called basiconic sensilla, which are found in the locusts’ antennae. Here, the molecule binds to a specific olfactory receptor, called OR35. Locusts engineered to lack this receptor are less attracted to 4VA, the authors report.

Based on their findings, the authors highlight several possible scenarios worthy of future exploration. If a synthetic version of 4VA was deployed in the wild, for example, it could potentially be used to lure locusts into traps where they could be killed. Alternatively, if a chemical that blocks the activity of the molecule was released, it might prevent the locusts from aggregating and migrating. Further research is needed to the test the feasibility of these and other related strategies.

doi: 10.1038/s41586-020-2610-4

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