Management practices that improve honey bee colony survivorship in the U.S.: Results from a multiyear national survey

Over the past 7 years, an average of one in three US overwintering colonies died (vanEngelsdorp et al., 2007 Am Bee J 147(7): 599–603, 2008 PLosONE 3(12), 2010 J.Apic.Res. 49(1): 7–14, 2011 J.Apic.Res.50(1): 1–10 and 2012 J.Apic.Res. 51(1): 115–124; Spleen et al., 2013 J.Apic.Res. 52(2): 44–53; Steinhauer et al., 2014 J.Apic.Res.53(1): 1–18). The losses suffered by beekeepers have not been consistent: some beekeepers consistently loose more colonies than others.  This suggests that more successful beekeepers (defined as those that loose fewer numbers of bees) either manage their colonies more effectively or run operations in areas that are more conducive to colony survivorship.

In attempt to identify management practices that resulted in the lowest mortality rates, we conducted an observational cross-sectional study design using retrospective surveys to record losses and management practices over the last 4 years. We used an innovative epidemiological approach to develop an expert-based model that ranks applied management practices in US beekeeping in order to identify what practices reduce colony losses the most. Based on the most complete year of the survey (2013-2014), we subjected our theoretical model to sensitivity analyses in order to develop a regional and operational size specific minimal adequate model (e.g. “best management practices”) which consider management factors such as varroa control methods, queen and comb management, and colony feeding regimes. It is hoped that the dissemination adoption of these findings will reduce annual rates of unsustainably high colony mortality.