Researchers from the University of Exeter estimated that every autumn, 17 million flies, wasps, butterflies, and dragonflies flood through a single 30-meter-wide pass between two peaks on the border between France and Spain. They captured this activity using video cameras and butterfly nets.
In the Pyrenees, one of Europe’s most well-liked winter vacation destinations, scientists have found the route that millions of insects travel every year as they migrate south across a high mountain pass.
Researchers from the University of Exeter captured an estimated 17 million flies, wasps, butterflies, and dragonflies streaming through a single 30-meter-wide opening using video cameras and butterfly nets.
Many are migrating to regions in southern Europe and north Africa with milder winters, such as the UK, from their northern summer ranges.
The researchers hypothesized that the 2,278-meter-high Pass of Bujaruelo was a major insect flyway.
A couple of British ornithologists initially noted swarms of marmalade hoverflies streaming across the pass more than 70 years ago. The common yellow-and black-striped flies of Europe can move 3,000 miles in the fall, according to current research.
