Honey bees, Varroa mites and unintended consequences

FEW PESTS are more feared by apiarists than the aptly named . This mite, originally a parasite of , the Asian honey bee, has plagued , ’s western cousin, for only 50 years or so—having arrived in Europe via what was then the Soviet Union and subsequently spread to both North and South America. But a plague it is. is now so common that the mites are found in nearly every hive in the United States.Why has proved so vulnerable is debated. It might be the case that, being naive to the new parasite, had evolved no defences against it. Individuals of , by contrast, constantly groom each other to remove such ectoparasites. But work by Alberto Satta and Francesco Nazzi of Sassari and Udine Universities, both in Italy, suggests an additional possibility. This is that beekeepers themselves have also, albeit unwittingly, helped the mites to multiply.