Popular insecticides called neonicotinoids are disrupting bumblebee life, according to a new study, causing big decreases in bee populations. Though the harm caused by this type of insecticide has been previously studied, researchers weren’t sure how it was causing increased bee deaths. The new study sheds light on that, finding that neonicotinoids disrupt nest life and colony thermoregulation.
The study, which was recently published in Science, found that this popular insecticide can decrease a bee colony’s viability even if the exposure is non-lethal. This effect is due to behavioral changes that decrease the bumblebees’ abilities to survive, namely in colony thermoregulation and nest activities.
During the research, bumblebees were observed continuously using automated equipment. Researchers noted that exposure to the levels of insecticide typically used in fields decreased a bee’s ability to nurse its young. As well, the insecticide was found to change the “social and spatial dynamics” of these nests.
The problems weren’t limited to just behavioral changes and also involved colony thermoregulation. Bees exposed to the insecticides were less capable of creating the wax canopy that insulated their nests, for example. These various disruptions contributed together to decrease the colony’s overall viability, the result being a greater than typical drop in bee populations.
A growing body of evidence pointing to neonicotinoid bee disruption has fueled a number of bans and restrictions. Earlier this year, European Union member states voted in favor of a ban on this insecticide that covers almost all usage scenarios. That followed a partial ban by the EU in 2013.