As a boy in the 1960s, David Wagner would run around his family’s Missouri farm with a glass jar clutched in his hand, scooping flickering fireflies out of the sky.

"We could fill it up and put it by our bedside at night,” says Wagner, now an entomologist.

That’s all gone, the family farm now paved over with new homes and manicured lawns. And Wagner’s beloved fireflies — like so many insects worldwide — have largely vanished in what scientists are calling the global Insect Apocalypse.