Specifically, they found that when bees are exposed to the enzyme p-coumaric, their immune system appears stronger—it turns on detoxification genes. P-coumaric is found in pollen walls, not nectar, and makes its way into honey inadvertently via sticking to the legs of bees as they visit flowers. Similarly, the team discovered other compounds found in poplar sap that appear to do much the same thing. It all together adds up to a diet that helps bees fight off toxins, the researchers report. Taking away the honey to sell it, and feeding the bees high-fructose corn syrup instead, they claim, compromises their immune systems, making them more vulnerable to the toxins that are meant to kill other bugs.