Density of wild honey bee, Apis mellifera, colonies worldwide

Abstract

The western honey bee, Apis mellifera, lives worldwide in approximately 102 million managed hives but also wild throughout much of its native and introduced range. Despite the global importance of A. mellifera as a crop pollinator, wild colonies have received comparatively little attention in the scientific literature and basic information regarding their density and abundance is scattered. Here, we review 40 studies that have quantified wild colony density directly (n = 33) or indirectly using genetic markers (n = 7) and analyse data from 41 locations worldwide to identify factors that influence wild colony density. We also compare the density of wild and managed colonies at a regional scale using data on managed colonies from the Food and Agriculture Organization (FAO). Wild colony densities varied from 0.1 to 24.2/km2 and were significantly lower in Europe (average of 0.26/km2) than in Northern America (1.4/km2), Oceania (4.4/km2), Latin America (6.7/km2) and Africa (6.8/km2). Regional differences were not significant after controlling for both temperature and survey area, suggesting that cooler climates and larger survey areas may be responsible for the low densities reported in Europe. Managed colony densities were 2.2/km2 in Asia, 1.2/km2 in Europe, 0.2/km2, in Northern America, 0.2/km2 in Oceania, 0.5/km2 in Latin America and 1/km2 in Africa. Wild colony densities exceeded those of managed colonies in all regions except Europe and Asia. Overall, there were estimated to be between two and three times as many wild colonies as managed worldwide. More wild colony surveys, particularly in Asia and South America, are needed to assess the relative density of wild and managed colonies at smaller spatial scales.

Assessing nest sites, survival rates and population dynamics of free-living honeybee colonies in Germany: A comparative study using personally collected and Citizen Science data

“…Yet, this belies the fact that the western honeybee is also present outside the realms of beekeeping and human husbandry (Grindrod and Martin, 2021;Visick and Ratnieks, 2023a) and how little is known about the formation and dynamics of this cohort. Currently, stable wild honeybee populations within their original range are known to exist in Africa and the Southern Ural, and outside their original range in the Americas and Australia (Schneider and Blyther, 1988;Moritz et al, 2007;Ilyasov et al, 2015b;Ratnieks et al, 1991;Seeley, 2007;Oldroyd et al, 1997).…”

“…Currently, stable wild honeybee populations within their original range are known to exist in Africa and the Southern Ural, and outside their original range in the Americas and Australia (Schneider and Blyther, 1988;Moritz et al, 2007;Ilyasov et al, 2015b;Ratnieks et al, 1991;Seeley, 2007;Oldroyd et al, 1997). Studies on these populations usually focus on habitats where managed and non-managed colonies are relatively separated, or where the density of wild colonies matches or surpasses that of managed colonies (Visick and Ratnieks, 2023a). However, the situation in Europe is different: Due to the fragmented landscape (Ibisch et al, 2016;Lesiv et al, 2019) and the high density of managed colonies (Phiri et al, 2022;Jones, 2004), there likely isn't a spatial or genetic barrier between managed and free-living colonies in most parts of Europe.…”