Why locusts swarm: scientists identify scent that could be used as weapon against plagues

The coronavirus isn’t the only plague making headlines this year – locusts are devastating crops in several parts of the world, and now scientists are discovering why the pest forms destructive swarms.On its own, a locust is fairly harmless. But so-called solitary locusts can undergo a metamorphosis, changing colour and joining together with millions of others in catastrophic clouds that strip fields.So what prompts locusts to transform from solitary to “gregarious”?A study published Wednesday…