A scientific note on the ‘Liebefeld Method’ to estimate honey bee colony strength: its history, use, and translation

Apis mellifera / colony development / colony strength / colony estimation / honey bee healthThe strength of honey bee (Apis mellifera ) colonies is vital for successful beekeeping.This parameter influences the amount of honey produced (Farrar 1937) and the number of foragers available to perform pollination services (Harbo 1986;Szabo and Lefkovitch 1989;Liebig 1993;Keller et al. 2005) and reflects its health and fitness (Imdorf et al. 2010;Dainat and Neumann 2013).Thus, there is a need for beekeepers and researchers interested in colony performance and vitality to have a reliable tool for measuring colony strength and development over time.Determining the status of a colony (i.e.healthy and productive or weak) requires the counting of thousands of highly mobile adult insects, of larvae lodged at the bottom of wax cells and of cells containing food stocks.A method allowing for such estimations was first described in 1987 in Apidologie in German.Here, we describe the history and principles of this easy, cost-efficient, reproducible and standardized field method that improved previous procedures and which later became known as the 'Liebefeld Method'.This method rapidly delivers reliable data on a large number of colonies, which is an advantage for beekeepers and researchers who require a large amount of high-quality field data.Although it has been widely used, the original language of the publication describing the estimation procedure likely reduced its international impact.Due to the continued relevance of this method today, the original article has been translated into English, and the citable article