Abstract:
Although pollinator declines are a global biodiversity threat, the demography of the western
honeybee (Apis mellifera) has not been considered by conservationists because it is biased by the activity of
beekeepers. To fill this gap in pollinator decline censuses and to provide a broad picture of the current status
of honeybees across their natural range, we used microsatellite genetic markers to estimate colony densities
and genetic diversity at different locations in Europe, Africa, and central Asia that had different patterns of
land use. Genetic diversity and colony densities were highest in South Africa and lowest in Northern Europe
and were correlated with mean annual temperature. Confounding factors not related to climate, however,
are also likely to influence genetic diversity and colony densities in honeybee populations. Land use showed a
significantly negative influence over genetic diversity and the density of honeybee colonies over all sampling
locations. In Europe honeybees sampled in nature reserves had genetic diversity and colony densities similar
to those sampled in agricultural landscapes, which suggests that the former are not wild but may have come
from managed hives. Other results also support this idea: putative wild bees were rare in our European
samples, and the mean estimated density of honeybee colonies on the continent closely resembled the reported
mean number of managed hives. Current densities of European honeybee populations are in the same range
as those found in the adverse climatic conditions of the Kalahari and Saharan deserts, which suggests that
beekeeping activities do not compensate for the loss of wild colonies. Our findings highlight the importance
of reconsidering the conservation status of honeybees in Europe and of regarding beekeeping not only as a
profitable business for producing honey, but also as an essential component of biodiversity conservation.
