Fight of the honeybees

A team of Spanish researchers who first tracked down an emerging pathogen in western honeybee populations may have found a cure for honeybee colony collapse disorder.

The team, led by Mariano Higes from the Centro Apicola Regional in Spain, investigated two professional apiaries suffering from the disorder, also known as colony depopulation syndrome.

They found evidence of infection by Nosema ceranae, a microsporidian that normally infects the Asiatic honeybee, Apis cerana.

This team reported in 2006 that the parasite had evolved to be able to infect the European or western honeybee, Apis mellifera, one of the most important pollinators of crops and fruit in the US and Europe.

The team treated the two apiaries with fumagillin, an antibiotic commonly used against N. ceranae, and were able to save the surviving bees.

There is still no consensus on what actually causes colony collapse disorder, with many culprits suspected. These include the Varroa destructor, a mite that lives off bees and spreads RNA viruses; Israeli acute paralysis virus, which some suspect was imported to the US by Australian honeybees, causing massive hive losses; or common neonicotinoid pesticides.

In a study published in a new journal from the UK’s Society for Applied Microbiology, Environmental Microbiology Reports, the researchers report finding no evidence in the two apiaries studied for any other pathogen except N. ceranae. Nor had the bees been out foraging in corn or sunflower crops, where they might come across insecticides.

The parasite works very fast to kill bees, particularly those who are out foraging and find themselves too weak to return to the hive. This is a noted symptom of colony collapse disorder: the unexplained disappearance of adult bees.