The world's vital insect kingdom is undergoing "death by a thousand cuts," the world's top bug experts said.

Climate change, insecticides, herbicides, light pollution, invasive species and changes in agriculture and land use are causing Earth to lose probably 1% to 2% of its insects each year, said University of Connecticut entomologist David Wagner, lead author in the special package of 12 studies in Monday's Proceedings of the National Academies of Sciences written by 56 scientists from around the globe.

The problem, sometimes called the insect apocalypse, is like a jigsaw puzzle. And scient...