BRING out your dead! Honeybees pick up dead or diseased nestmates and drag them out of the hive. Removing corpses protects against infection, which can spread like wildfire in densely packed hives.
鈥淭he honeybees work together to fight off disease,鈥� says at the University of British Columbia, Canada. But not all hives remove their corpses. McAfee and her colleagues have been figuring out why this is.
In , they discovered two pheromones, called oleic acid and beta-ocimene, which are only released by dead bee larvae. When they wafted these 鈥渄eath pheromones鈥� over honeybees, nerve cells in the antennae of corpse-removing bees were more active than those of other bees. This suggested that corpse-removing bees were better able to smell the pheromones.
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Now the team has added the pheromones to healthy larvae. As expected, worker bees removed dosed individuals from the nest, and bees from corpse-removing colonies removed more larvae than those from other nests (, ).
The corpse-removing bees鈥� ability to smell death could be down to two proteins on their antennae, OBP16 and OBP18. These are largely absent from bees that don鈥檛 remove corpses. 鈥淭hese proteins grab onto the odour molecules, transport them to the neurons and stimulate them, leading to a sense of smell,鈥� says McAfee.
鈥淏ees were bred to express proteins linked to corpse removal. They removed more of their dead鈥�
The research could allow us to selectively breed bees that make the two proteins, and hence remove their dead. Corpse-free hives are better at fighting off infections.
In , the team selectively bred bees to express 13 proteins linked to corpse removal, including OBP16 and OBP18. After three generations, the colonies removed more of their dead, and were more resistant to several diseases.
This article appeared in print under the headline 鈥淪mell of death leads bees to remove corpses鈥�
