Bees may be small, but they play a big role in human health and survival. Some experts say one of every three bites of food we eat depends on them. The insects pollinate everything from apples and zucchini to blueberries and almonds. If bees and other pollinators are at risk, entire terrestrial ecosystems are at risk, and so are we.Well, pollinators are at risk. And we know one of the main causes of their alarming death rates. A new report concludes that neonicotinoid pesticides, or neonics, "pose a serious risk of harm to honey bees and other pollinators." They also harm butterflies, earthworms and birds, and because they're now found in soils, sediment, groundwater and waterways, they alter "biodiversity, ecosystem functioning and the ecosystem services provided by a wide range of affected species and environments." The report, produced by the Task Force on Systemic Pesticides, is the work of 50 independent scientists from around the world who spent four years analyzing more than 800 peer-reviewed scientific studies. "Far from protecting food production, the use of neonics is threatening the very infrastructure which enables it, imperilling the pollinators, habitat engineers and natural pest controllers at the heart of a functioning ecosystem," says lead author Jean-Marc Bonmatin of the National Centre for Research in France. Other research shows they may not even increase agricultural yields.