Analysis of worker bees indicates that individuals from the brood nest contain more bacteria than bees from flight entrances; therefore, it was suggested that samples of bees are preferably collected from the brood nest (Roetschi et al., 2008). This result has not been replicated by others, where the amount of M. plutonius in foragers equalled that found in nurse bees (Budge, unpublished data). Pooled samples of 100 bees have been used for DNA extraction (Roetschi et al., 2008; Budge et al., 2010); however, adult bees show more variation in the amount of M. plutonius detected than samples of larvae (Fig. 3).
Fig. 3. Estimates of the log amount of M. plutonius (MNE) in samples of larvae (A) and adult bees (B) probability of the honey bee colony being symptomatic for EFB. Data from 2006 are from Budge et al. (2010), and those from 2007 previously unpublished findings from follow up work. The plots represent estimates and corresponding 95% confidence limits from a generalized linear model constructed using qPCR data (see Budge et al., 2010).