the key might be that durring the torpor of hibernation the bees are less vulnerable to toxins than there parasites first question is do the parasites also hibernate or do they continue to feed on the bees,while the bees have crawled into a chemical spill and put themselves into suspended animation for 3-4 months and keep in mind that many insect species feed on toxic plants to deter preditors, monarch butterflys and milk weed is top of the list