Propolis (yellow) lining the inside of a beehive.
Beekeepers would love to get rid of propolis, a sticky substance made of resins that bees use to line their hives, because it makes it hard to pry hives open. But propolis isn’t just gluing the hive together, according to a new study published in PLoS ONE—honeybees use it to fight off fungal infections and seek it out when their hives are infected.
Bees have to invest effort in hunting down the resins that make up propolis, which like nectar is foraged from plants. That means that every minute a bee is looking for resin is a minute it’s not looking for food. The trade-off is worth it, apparently, because propolis kills bacteria and fungi lurking in the colony.
Honey bees tagged with RFID chips
The mysterious drop in honey bee populations—often called colony collapse disorder for lack of a more specific name—has generated a long list of suspects that includes mites, viruses, malnutrition, and even cell phone radiation. Two new studies published in Science suggest that neonicotinoids, a class of widely used insecticides, may belong at the top of the list.
That an insecticide kills insects like bees is not particularly surprising. Neonicotoinoids have already been partially banned in Italy, Germany, and France for their possible role in colony collapse disorder. Still, it remains one of the most common pesticides: one neonicotoinid alone, imidacloprid, is authorized for use on over 140 crops in 120 countries. Results from the two new studies suggest that even doses that do not kill the bee immediately can have enough ill effect to eventually cause colony collapse.