Migration and trans-Atlantic flight of locusts

African desert locusts (Schistocerca gregaria) crossed the Atlantic from West Africa to the Caribbean in 1988, a non-stop flight of about 5000 km. Although this migration was assisted by winds, the locusts had to actively maintain altitude and to fly for 4-6 days. Locusts are known to be outstanding flyers that migrate for thousands of kilometres over land, but this trans-Atlantic flight seems to be beyond their capacity. A phenomenon called phase polymorphism, inherent to all locusts sensu stricto, helps them to perfectly adapt to their ephemeral habitat and assists the formation of giant locust swarms with incredible flight performance. The present review briefly summarises the locust ecology, behaviour, physiology and morphology that are associated with the phase polymorphism and outlines the climatic conditions that may lead to such long-range displacements.