It turns out the mysterious decline of bee populations in the U.S. and elsewhere might not be all that mysterious after all. Pesticides produced by a unit of Germany's Bayer may be directly or indirectly contributing. The collapse of 30% to 90% of some bee populations over the past few years is a problem to buzz about. Billions of dollars in U.S. food, including nuts, berries, fruits and vegetables, come from plants that rely on bees to pollinate them, according to the USDA. And there will be less honey to go around as the bees that make it disappear. Whether or not Bayer was in the wrong, this unfolding story serves as a reminder to consumers. It's up to each of us to err on the side of caution and minimize our exposure to chemicals -- even those that have been declared "safe." Sometimes only time can tell us what's good for humans and the environment. Germany recently banned several of Bayer's nicotine-based insecticides, following a move that France made several years ago. The chemicals in questions are used to cover seeds before they're sown and work their way through the plant's system. As a result, bees might ingest them through the pollen they pick up. Some researchers say this pesticide is harming bees' nervous system, making them more vulnerable to diseases and pests. It's not hard to believe that something meant to harm pests might also harm other small critters as well.