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Title: First analysis of risk factors associated with bee colony collapse disorder by classification and regression trees

Author
item Vanengelsdorp, Dennis - Pennsylvania Department Of Agriculture
item Speybroeck, Niko - Catholic University Of Leuven
item Evans, Jay
item Nguyen, Bach Kim - Gembloux Agricultural University
item Mullin, Chris - Pennsylvania State University
item Frazier, Maryann - Pennsylvania State University
item Frazier, Jim - Pennsylvania State University
item Cox-foster, Diana - Pennsylvania State University
item Chen, Yanping - Judy
item Tarpy, David - North Carolina State University
item Haubruge, Eric - Gembloux Agricultural University
item Pettis, Jeffery
item Saegerman, Claude - University Of Liege

Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2009
Publication Date: 10/1/2010
Citation: Vanengelsdorp, D., Speybroeck, N., Evans, J.D., Nguyen, B., Mullin, C., Frazier, M., Frazier, J., Cox-Foster, D., Chen, Y., Tarpy, D., Haubruge, E., Pettis, J.S., Saegerman, C. 2010. First analysis of risk factors associated with bee colony collapse disorder by classification and regression trees. Journal of Economic Entomology. 103:1517-1523.

Interpretive Summary: Sudden losses of managed honey bee colonies are considered an important problem worldwide but the underlying cause or causes of these losses are currently unknown. In the United States, this syndrome was termed Colony Collapse Disorder (CCD), since the defining trait was a rapid loss of adult worker bees. We conducted an analysis in order to understand the relative importance among different risks in explaining CCD. The analysis showed that CCD is likely the result of several factors acting in concert, with the combination decreasing colony strength and making CCD colonies more susceptible to disease. This analysis highlighted several areas that warrant further attention, including the effect sub-lethal pesticide exposure has on pathogen expression and the role of bee tolerance to pesticides on colony survivorship. This information will be useful to other researchers to design experiments that explore bee health issues and the role of pesticides and pathogens on CCD.

Technical Abstract: Sudden losses of managed honey bee (Apis mellifera L.) colonies are considered an important problem worldwide but the underlying cause or causes of these losses are currently unknown. In the United States, this syndrome was termed Colony Collapse Disorder (CCD), since the defining trait was a rapid loss of adult worker bees. We conducted a classification and regression tree (CART) analysis in order to understand the relative importance and inter-relations among different explanatory risk variables in explaining CCD. Using a CART model with a specified cost of misclassification, we obtained a tree with a sensitivity of 100% and a specificity of 67%. With this model, CCD was characterized mostly by a low level of coumaphos (a miticide commonly used by beekeepers) in brood and beebread, smaller colony size as measured but frames of bees, physiological disturbances which suggest decreased colony fitness (lower mass of the head and increased fluctuating asymmetry), and increased viral loads. The CART analysis provides further evidence that CCD is likely the result of several factors acting in concert, with the combination decreasing colony fitness and making afflicted colonies more susceptible to disease. This analysis highlighted several areas that warrant further attention, including the effect of sub-lethal pesticide exposure has on pathogen expression, the role of variability in bee tolerance to pesticides on colony survivorship, and the consequences of pathology on bee physiology.