Nearly 1/3 of honey bees have perished in just a few years, and honeybees pollinate 1/3 of all the food we eat. This is a closer look at a major cause of widespread bee die-offs, what it means to us, how we can help.When the sweet life goes sour. Let's start with pesticides.How 'neonics' harm honey bees.A picnic without bees. Honey bees are critical to U.S. food supplies. 1/3 of the foods we eat are pollinated by honey bees.The big picture: Honey production is the best overall indicator of bees' health. That's because sick bees make less honey. Here's a look at U.S. honey production since the bee killing class of pesticides neonicotinoids came into the picture.