All of a flutter: how butterflies avoid being a predator’s lunch

A European swallowtail butterfly and its motion trail, which is thought to confuse predators. Photograph: George Hancock

Naturalists have long wondered how brightly coloured butterflies manage to evade the attention of birds that make a meal of other insects.

New research from British ecologists suggests it is not simply a matter of good luck but instead a visual illusion created by their fluttering wings.