There's no denying it. Pesticides are harming bees.

By now you've probably heard about colony collapse disorder, the recent phenomenon in which an unprecedented number of honeybees have died. Increasingly, colony collapse disorder, or CCD, is linked to chemical pesticides. The unfortunate situation threatens not only honeybees, but also human food production and food prices. After all, bees are responsible for pollinating most of the foods we eat today.

The demise of other winged critters is now giving us more reason to believe that certain pesticides—or a combination of the chemicals—are at the root of the problem. New research published in the journal Nature found that exposing social bumblebees to levels of two pesticides they are likely to encounter in fields makes it hard for the bees to perform daily duties and be part of a thriving colony.

Scientists exposed the bees to levels of a popular neonicotinoid (imidacloprid) and a pyrethroid, commonly found in nectar or sprayed in fields. The bees were allowed to forage in a natural setting.

Bees exposed to imidacloprid were poorer foragers and were more likely to get lost when leaving the colony; they also had more trouble collecting pollen. This meant less food for the colony, which reduced its population as well as its chances of surviving.

This may not come as a huge surprise, given the way imidacloprid kills agricultural insect pests. The synthetic chemical disrupts a critter's neurological functioning, harming the nerves' natural ability to send a normal signal. It's also a systemic insecticide, meaning it's taken up inside of the plant and many of the foods we eat. Imidacloprid residues are commonly detected on nonorganic spinach, kale, and other greens at levels the Environmental Protection Agency consider safe.

This is the first study of its kind to show how a combination of pesticides can affect a colony, and how chemical exposures of individual bees can harm the entire colony. It also provides more evidence that pesticides harm other types of important pollinators, too, not just honeybees.

The truth is that pesticides—and many other modern-day chemicals—aren't tested to determine their long-term impact on animals or humans.

For more information on how farming chemicals could be affecting humans, read 7 Crazy Things Pesticides Are Doing to Your Body.