Butterflies crossing oceans, moths navigating by the stars: unravelling the mysteries of insect migrations

Trillions of insects embark, largely unnoticed, on epic journeys every year across mountain ranges, deserts and seas, and it is only now, as their numbers suffer huge declines, that scientists are tracking their movementsOn a cloudless sunny day in October 1950, ornithologists Elizabeth and David Lack stood on a mountain pass in the Pyrenees and observed a once-in-a-lifetime spectacle - clouds of migrating insects.Up to 500 butterflies were fluttering past them every hour through the 2,200m-high Puerto de Bujaruelo mountain pass on the French-Spanish border. By mid-afternoon dragonflies were skimming through, outnumbering the butterflies by 10 to one. The spaces between were filled with thousands of tiny flies. Continue reading...