Honey bee colony loss rates in 37 countries using the COLOSS survey for winter 2019–2020: the combined effects of operation size, migration and queen replacement

Abstract

This article presents managed honey bee colony loss rates over winter 2019/20 resulting from using the standardised COLOSS questionnaire in 37 countries. Six countries were from outside Europe, including, for the first time in this series of articles, New Zealand. The 30,491 beekeepers outside New Zealand reported 4.5% of colonies with unsolvable queen problems, 11.1% of colonies dead after winter and 2.6% lost through natural disaster. This gave an overall colony winter loss rate of 18.1%, higher than in the previous year. The winter loss rates varied greatly between countries, from 7.4% to 36.5%. 3216 beekeepers from New Zealand managing 297,345 colonies reported 10.5% losses for their 2019 winter (six months earlier than for other, Northern Hemisphere, countries). We modelled the risk of loss as a dead/empty colony or from unresolvable queen problems, for all countries except New Zealand. Overall, larger beekeeping operations with more than 50 colonies experienced significantly lower losses (p < 0.001). Migration was also highly significant (p < 0.001), with lower loss rates for operations migrating their colonies in the previous season. A higher proportion of new queens reduced the risk of colony winter loss (p < 0.001), suggesting that more queen replacement is better. All three factors, operation size, migration and proportion of young queens, were also included in a multivariable main effects quasi-binomial GLM and all three remained highly significant (p < 0.001). Detailed results for each country and overall are given in a table, and a map shows relative risks of winter loss at the regional level.

Four-Year Overview of Winter Colony Losses in Greece: Citizen Science Evidence That Transitioning to Organic Beekeeping Practices Reduces Colony Losses

“…Most regions followed the same pattern of queen replacement ( Supplementary Table S2 ). Previous work has identified that queen replacement has a direct impact on hive losses [ 40 , 41 , 48 ]. Therefore, we investigated whether the loss rate per beekeeper correlated with their respective queen replacement rate.…”

“…In an effort to address bee issues, as well as the compartmentation of existing research, in 2008, the international scientific research association “COLOSS” (Prevention of COlony LOSSes) was founded, to connect honey bee experts, reinforce their scientific collaboration and improve the well-being of honey bees on a global scale [ 18 , 37 ]. One of its core activities since the very start [ 38 ] has been the Citizen Science “Colony Losses Monitoring” project [ 39 ], which is currently active in many countries from Europe and the rest of the world [ 40 , 41 , 42 ]. The objective of this group effort is to collect and report internationally comparable data [ 43 ] concerning colony mortality during winter—the most critical season for colony losses for most European countries [ 44 ].…”

“…This is achieved through a standardized questionnaire and specific research protocol [ 45 ] that facilitate comparison between different countries, in order to identify factors with positive or negative effects on colony survival and reassess existing beekeeping practices to prevent future losses [ 46 ]. Previous analysis of COLOSS questionnaires, both at multi-country [ 40 , 41 , 42 , 44 , 47 , 48 , 49 ] and regional level [ 50 , 51 , 52 , 53 , 54 ], have set a basis for reference loss rates while investigating a combination of stressors and hive-management factors.…”

Population genetic diversity and dynamics of the honey bee brood pathogen Melissococcus plutonius in a region with high prevalence

“…Consequently, A. mellifera is one of the most commonly managed insects in the world. The large-scale losses of managed colonies reported in recent times in the Northern Hemisphere potentially threaten the services honey bees provide ( Decourtye et al, 2019 , Gray, 2022 , Kulhanek et al, 2017 , Liu et al, 2016 , Neumann and Carreck, 2010 , Potts et al, 2010 , Steinhauer et al, 2018 ). Honey bee health has thus become a major concern for scientists, policy-makers, beekeepers and the public ( Evans and Schwarz, 2011 , Moritz et al, 2010 , Smith et al, 2013 ).…”

Increased survival of honey bees consuming pollen and beebread is associated with elevated biomarkers of oxidative stress

“…The western honey bee, Apis mellifera L. (Hymenoptera: Apidae), is an important pollinator in natural and agricultural ecosystems (Potts et al, 2010;Garibaldi et al, 2017;Khalifa et al, 2021). Significant bee colony losses have been observed worldwide in recent decades (Gray et al, 2019(Gray et al, , 2022. This issue has drawn particular attention to identifying factors that negatively affect honey bee health, and it is believed that poor nutrition may be one of them.…”