Exposure to very low levels of neonicotinoids negatively affects bumblebee brains
A recent study published in the journal of the Federation of American Societies for Experimental Biology has found further support that exposure to very low levels of neonicotinoid pesticides, comparable to what is found in nectar and pollen from neonicotinoid-treated crops, is sufficient to harm bees. Researchers carried out a combination of laboratory and field studies in order to determine the effect that very low exposures to neonicotinoid pesticides had on bumblebee brains and hive health. In laboratory tests, bees were fed 2.1 parts per billion of pesticides in sugar water. The bee’s brains were monitored, and scientists observed that within three days, the pesticides had accumulated in the brain enough to negatively affect the mitochondria, the primary source of cellular energy. This disruption to brain cells is enough to impair brain function, leading to learning and recognition problems that ultimately hurt the health of the hive. They then fed these low levels of neonicotinoids to bees in hives placed on undisturbed land where they would not have access to floral resources with additional pesticide contamination. They found that in these hives, the size of the colony was reduced by half; the number of brood cells fell by over 70 percent, and the mass of the bee nest declined by over 50 percent.