Weighing Risk Factors Associated With Bee Colony Collapse Disorder by Classification and Regression Tree Analysis

Abstract

31Colony Collapse Disorder (CCD), a syndrome whose defining trait is the rapid loss of adult worker honey 32 bees, is thought to be responsible for a minority of the large over-wintering losses experienced by U.S. 33 beekeepers since the winter of 2006-2007. Using the same data set developed to perform a mono-34 factorial analysis (vanEngelsdorp et al. 2009), we conducted a classification and regression tree (CART) 35 analysis in an attempt to better understand the relative importance and inter-relations among different risk 36 variables in explaining CCD. Fifty-five exploratory variables were used to construct two CART models: 37 one with and one without a cost of misclassifying a CCD-diagnosed colony as a non-CCD colony. The 38 resulting model tree which permitted for misclassification had a sensitivity and specificity of 85% and 39 59% respectively. While factors measuring colony stress (e.g., adult bee physiological measures such as 40 fluctuating asymmetry or mass of head, and morphological measures such as frames of brood) were 41important discriminating values, 6 of the 19 variables having the greatest discriminatory value were 42 pesticide levels in different hive matrices. Notably, coumaphos levels in brood (a miticide commonly 43 used by beekeepers) had the highest discriminatory value and were highest in control (healthy) colonies. 44Our CART analysis provides evidence that CCD is likely the result of several factors acting in concert, 45 making afflicted colonies more susceptible to disease. This analysis highlights several areas that warrant 46 further attention, including the effect of sub-lethal pesticide exposure on pathogen prevalence and the role 47 of variability in bee tolerance to pesticides on colony survivorship. 48 49

Landscape and pesticide effects on honey bees: forager survival and expression of acetylcholinesterase and brain oxidative genes

“…Despite the ongoing debates regarding the causes of honey bee decline around the world, a majority of the scientific community considers this decline to be a multifactorial phenomenon (VanEngelsdorp et al 2010;Wu et al 2012). This means that no single factor-such as pathogens and parasites (Fries 2010;Dainat et al 2012), insufficient experience in honey bee hive management, or excessive use of pesticides (Johnson et al 2010; Van der Sluijs et al 2013)-is individually causing honey bee decline or mortality, but the contribution of various factors acting together are responsible.…”

Rising atmospheric CO2is reducing the protein concentration of a floral pollen source essential for North American bees

“…B 283: 20160414 autumn population was positively correlated with the amount of stored pollen. In general, for temperate climates, early spring is recognized as a time of pollen protein shortages and colony starvation [22,27,35].…”

“…Varroa destructor or Nosema ceranae), which, in turn, can feedback to exacerbate nutritional stress [19][20][21]. Good nutrition can also aid in pesticide detoxification [22][23][24].…”

Genomic characterization and phylogenetic analysis of Chinese sacbrood virus isolated from Loess Plateau, China

“…Sacbrood virus (SBV) is one of the most common and widespread of the 19 viruses known to infect honeybees (Chen and Siede, 2007;Neumann and Carreck, 2010;VanEngelsdorp et al, 2010). SBV infects both larvae and adult bees, and there are no disease symptoms in SBV-infected adult bees (Berényi et al, 2007).…”