Over the last quarter century, increasing honey bee colony losses motivated standardized large-scale surveys of managed honey bees (Apis mellifera), particularly in Europe and the United States. Here we present the first large-scale standardized survey of colony losses of managed honey bees and stingless bees across Latin America. Overall, 1736 beekeepers and 165 meliponiculturists participated in the 2-year survey (2016–2017 and 2017–2018). On average, 30.4% of honey bee colonies and 39.6% of stingless bee colonies were lost per year across the region. Summer losses were higher than winter losses in stingless bees (30.9% and 22.2%, respectively) but not in honey bees (18.8% and 20.6%, respectively). Colony loss increased with operation size during the summer in both honey bees and stingless bees and decreased with operation size during the winter in stingless bees. Furthermore, losses differed significantly between countries and across years for both beekeepers and meliponiculturists. Overall, winter losses of honey bee colonies in Latin America (20.6%) position this region between Europe (12.5%) and the United States (40.4%). These results highlight the magnitude of bee colony losses occurring in the region and suggest difficulties in maintaining overall colony health and economic survival for beekeepers and meliponiculturists.

Honey bee colony losses during winter are a multi-factorial phenomenon. Environmental conditions, beekeeping practices and different pathogens are all considered as potential causes of honey bee colony losses. However, these factors may be diverse in different regions and there are no regional studies about winter losses in South America. The objective of this study was to identify risks factors associated with winter losses in temperate climate honey bee colonies in Argentina. Parasitic mite infestation level, colony strength measures, and percentage of colonies losses during winter 2013 were evaluated in 62 apiaries distributed in four different regions in east-central Argentina. Data regarding management practices in each apiary were collected by means of a questionnaire. A logistic regression model was constructed to associate management variables with the risk of winter losses higher than 10% of the colonies. Beekeepers who reported replacing less than 50% of the queens in their apiaries showed higher winter losses than apiaries who replaced more than 50% of their queens (OR = 18.15; CI 95%: 1.76–187.43; p = 0.01). There were no significant spatial clusters detected in our analysis (p > 0.05). Even considering that the winter colony losses can be explained by a complex interaction of factors, requeening appears as one of the most important management practices to reduce this phenomenon in Argentina.

Nosema apis and Nosema ceranae are obligate parasites that develop within the honey bee gut reducing the life of their host. The role that they have in colony losses is not clear, and it remains to be elucidated how the geographical and seasonal variations influence pathogenicity of nosema. The aim of this study was to identify risk factors associated with the abundance of Nosema spp. spores in apiaries located in temperate and subtropical regions after honey harvest. A total of 361 colonies distributed in five eco-regions of Argentina were examined to evaluate the abundance of Nosema spp. spores. Regions differed with regard to temperature, precipitation, and vegetation landscape. The abundance of Nosema spp. spores was significantly higher in temperate than in subtropical regions. A south-north gradient of Nosema spp. spore abundance was found, with the highest spore counts observed in South Santa Fe, continuously descending towards the northern regions of higher temperature. The observed gradient may be related to weather conditions and/or availability of floral resources in each eco-region. Also, colonies with >3% of Varroa destructor infestation showed the highest abundance of Nosema spp. spores. N. ceranae, N. apis, and co-infection were identified in 37.77, 26.66, and 35.55% of the studied colonies, respectively.