A pheromone molecule that makes crop-damaging locusts swarm has been identified. Could this pheromone, which is sensed by odorant receptors, be used to trap these insects and prevent the agricultural devastation that they cause?

This year is a plague year. The COVID-19 pandemic, caused by the coronavirus SARS-CoV-2, is burning across the globe as we anxiously await an effective vaccine or drug to control it. Another plague, of a much older kind — one that is not curable with vaccines or medicine — is currently raging in Africa (Fig. 1) and the Middle East. Seasons of unusually heavy rains, driven by climate change,have created population explosions of swarming desert locusts (Schistocerca gregaria). Swarms can contain billions of insects and cover hundreds of square kilometres. These insects strip vegetation and crops, threatening the precarious existence of subsistence farmers and contributing to food insecurity in vulnerable regions. The only effective weapon for fighting such locust plagues is the aerial spraying of pesticides, but the swarms are fast-moving and unpredictable, and spraying devastates beneficial insects.

How do these vast swarms of voracious insects form, and what can be done to stop them? Writing in Nature, Guo et al.1 identify a pheromone molecule of the migratory locust (Locusta migratoria) that might hold the key to swarming behaviour, and the authors’ discovery raises the possibility of using locusts’ own pheromone to combat this threat.