The wild honeybee population of Europe is in decline: evidence from monitoring studies

Patrick Laurenz Kohl , Benjamin Rutschmann

Populations of wild western honeybees (Apis mellifera) have been neglected because the species has been considered to consist of managed colonies only. New data suggest that wild colonies (still) make up at least one sixth of the overall European honeybee population. Their population trends can be evaluated like those of other species, albeit with some methodological adjustments to account for the bias introduced by swarms emigrating from apiaries. We used data on the annual survival rates of free-living colonies from seven European countries and assumed a realistic swarming rate of two swarms per colony per year to estimate the intrinsic growth rates of wild populations. Observed variation in nest site reoccupation rates among years was taken as a measure of environmental stochasticity in population performance. We then simulated the autonomous wild population changes over ten-year periods, the time frame considered for assessments by the IUCN. Wild honeybee populations still exist in five of the seven countries with data, but they currently act as demographic sinks in most regions. With an estimated median population decline of 56% per decade, the honeybee can be considered “Endangered in the wild” at the European level. (For future updates on the population status see https://doi.org/10.5281/zenodo.18424042.)