Colony losses monitoring

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The colony loss monitoring group has been active since the start of the COLOSS COST action, now the COLOSS Association, to study reasons for colony losses.

Participating countries each carry out an annual survey of beekeepers by questionnaire, with the aim of collecting information from a nationally representative sample of beekeepers. This makes it possible to compare colony loss rates between countries and to use the international data collected to understand better the risk factors for colony loss. To enable proper comparisons, a standardised beekeeper questionnaire was developed and is updated each year by the group for use by each country. We also contributed a chapter on standard survey methodology to the COLOSS BEEBOOK (van der Zee et al., 2013).

About 30 countries currently participate in monitoring, mainly but not exclusively in the northern hemisphere, with others interested. The number of member countries is continually increasing. At the individual level, many thousands of beekeepers take part each year. This is an example of citizen science/crowdsourcing, with the voluntary participation of many beekeepers enabling much wider scale data collection than would otherwise be possible.

Participating countries return their data for analysis annually before an agreed deadline, usually 1st of July, and the results are used for press releases and scientific publications. We produce jointly authored journal papers for dissemination of results to the research community. Our publications not only produced for the first time internationally comparable loss rates of honey bee colonies, but have also used advanced statistical modelling to investigate risk factors. The risk factors identified so far include beekeeper management (such as treatment strategies to control the parasitic mite Varroa destructor, and the age of queens), operation size, and environmental factors (e.g. local weather or certain forage available to honey bee colonies).


Brodschneider, R., Gray, A. (2021). How COLOSS Monitoring and Research on Lost Honey Bee Colonies Can Support Colony Survival. Bee World Volume 99, 2022 – Issue 1: A Special Issue on COLOSS, Pages 8-10. Full Article

Brodschneider, R., Schlagbauer, J., Arakelyan, I., Ballis, A., Brus, J., Brusbardis, V., … & Gray, A. (2022). Spatial clusters of Varroa destructor control strategies in Europe. Journal of Pest Science, 1-25. Full Article

Gray, Adjlane, Arab, Ballis, Brusbardis, Bugeja Douglas, Cadahía, Charrière, Chlebo, Coffey, Cornelissen, da Costa, Danneels, Danihlík, Dobrescu, Evans, Fedoriak, Forsythe, Gregorc, Ilieva Arakelyan, Johannesen, Kauko, Kristiansen, Martikkala, Martín-Hernández, Mazur, Medina-Flores, Mutinelli, Omar, Patalano, Raudmets, San Martin, Soroker, Stahlmann-Brown, Stevanovic, Uzunov, Vejsnaes, Williams, Brodschneider, R. (2022). 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. Journal of Apicultural Research, 1-7. Full Article

Brodschneider, Gray, Adjlane, Ballis, Brusbardis, Charrière, Chlebo, Coffey, Dahle, de Graaf, Dražić, Evans, Fedoriak, Forsythe, Gregorc, Grzęda, Hetzroni, Kauko, Kristiansen, Martikkala, Martín-Hernández, Medina-Flores, Mutinelli, Raudmets, Ryzhikov, Simon-Delso, Stevanovic, Uzunov, Vejsnæs, Woehl, Zammit-Mangion, Danihlík (2018) Multi-country loss rates of honey bee colonies during winter 2016/17 from the COLOSS survey. Journal of Apicultural Research, 57(3), 452-457. Full Article

Brodschneider, Gray, van der Zee, Adjlane, Brusbardis, Charrière, Chlebo, Coffey, Crailsheim, Dahle, Danihlík; Danneels, de Graaf, Dražić, Fedoriak, Forsythe; Golubovski, Gregorc, Grzęda, Hubbuck, İvgin Tunca, Kauko, Kilpinen, Kretavicius, Kristiansen, Martikkala, Martín-Hernández, Mutinelli, Peterson, Otten, Ozkirim, Raudmets, Simon-Delso, Soroker, Topolska; Vallon; Vejsnæs, Woehl (2016) Preliminary analysis of loss rates of honey bee colonies during winter 2015/16 from the COLOSS survey. Journal of Apicultural Research, 55: 375-378. Full Article

van der Zee, Brodschneider, Brusbardis, Charrière, Chlebo, Coffey, Dahle, Drazic, Kauko, Kretavicius, Kristiansen, Mutinelli, Otten, Peterson, Raudmets, Santrac, Seppälä, Soroker, Topolska, Vejsnæs, Gray (2014) Results of international standardised beekeeper surveys of colony losses for winter 2012-2013: analysis of winter loss rates and mixed effects modelling of risk factors for winter loss. Journal of Apicultural Research 53: 19-34. Full Article

van der Zee, Gray, Holzmann, Pisa, Brodschneider, Chlebo, Coffey, Kence, Kristiansen, Mutinelli, Nguyen, Adjlane, Peterson, Soroker, Topolska, Vejsnæs, Wilkins (2013) Standard survey methods for estimating colony losses and explanatory risk factors in Apis mellifera. In V Dietemann; J D Ellis; P Neumann (Eds) The COLOSS BEEBOOK, Volume I: Standard methods for Apis mellifera research. Journal of Apicultural Research 52(4): Full Article

van der Zee, Pisa, Andonov, Brodschneider, Charrière, Chlebo, Coffey, Crailsheim, Dahle, Gajda, Gray, Drazic, Higes, Kauko, Kence, Kence, Kezic, Kiprijanovska, Kralj, Kristiansen, Martin Hernandez, Mutinelli, Nguyen, Otten, Özkırım, Pernal, Peterson, Ramsay, Santrac, Soroker, Topolska, Uzunov, Vejsnæs, Wei, Wilkins (2012) Managed honey bee colony losses in Canada, China, Europe, Israel and Turkey, for the winters of 2008-9 and 2009-10. Journal of Apicultural Research 51: 100-114. Full Article


To communicate with beekeepers in the participating countries the national co-ordinators write articles for their respective beekeepers’ journals, and/or post results on a relevant website, for example the Austrian website at:

Older press releases can be found here: << Press releases >>


We have an email discussion list for our monitoring group. We welcome participation by new countries wishing to join in monitoring.

We also have a ResearchGate project for updates, news and expressions of interest, at:


Are you interested in joining this COLOSS core project?

If so, please contact one of the core project co-chairs below.



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