For some, cleanliness is next to godliness. For honeybees, which are suffering a major decline, it’s a way of saving the hive from disaster. A naturally-occurring cleaning behaviour protects colonies from harmful parasitic mites, and breeding bees to be more hygienic could protect hives from the viruses they spread.
The varroa mite sucks the blood of pupae of worker bees, reducing their immunity to disease and transmitting viruses. Mites sneak into the honeycombs, then lay their eggs and feed on the larvae in the safety of the wax-capped cells. When the cells are uncapped to release the adult bees the mites are also released – ready to parasitise other members of the hive.
Bees that have been trapped with mites are often smaller, and can show signs of infection with a disease called deformed wing virus. If present together, varroa mites and this virus can kill off a whole hive, particularly during the difficult winter months.
But hygienic worker bees can save the day. They sniff out dead or diseased larvae, uncap their cells and dispose of the contents. Although any adult mites inside may survive this upheaval, their young offspring are killed. This cleaning behaviour, if done intensively, is highly effective at controlling mite numbers and protects the hive against deformed wing virus.