Prevalence of Honeybee Colony Collapse Disorder and its Relation to Nosema Spp. and Climate in Apiaries of Iran

Colony Collapse Disorder is a mysterious phenomenon in which worker bees abruptly disappear from a beehive. The aim of this study was to estimate the prevalence of CCD and its relation to climate and Nosema spp infections. This Cross sectional study was done from April to September 2016. With respect to different climatic zones of the country, a total of 183 ‎apiaries were selected. In each apiary, 5 percent of the colonies were ‎randomly sampled. Adult bee samples were then examined for the presence of Nosema infections using PCR. Data were analyzed by Chi-square using SPSS version 21.0. The results showed the prevalence of colony collapse disorder in the studied apiaries at 26.8%. The CCD prevalence was ‎20.5% in ‎humid, ‎16.1% in semi humid‎, ‎22.7% in very humid, 38.2% in arid, ‎43.8% in semi-‎arid and ‎16% in Mediterranean conditions. Comparing CCD phenomenon in different climatic regions, there were significant differences (P<0.05). The prevalence of Nosema ceranae infection was 85 (46.4%), however, infection with Nosema apis was not observed in the samples either in pure form or as ‎associated infection. There was no statistical significant difference between symptomatic and asymptomatic apiaries with colony collapse disorder in terms of presence or absence of N.ceranea (P>0.05).   The results suggest that climate could influence the prevalence of Colony Collapse Disorder. It may be due to different foraging resources in under studied area. According to findings of this study it seems that N.ceranea alone cannot be the cause for CCD. Further studies are needed to clarify the interactions between climate and other possible causes.