Genetic diversity and prevalence of Varroa destructor, Nosema apis, and N-ceranae in managed honey bee (Apis mellifera) colonies in the Caribbean island of Dominica, West Indies

摘要

Honey bees (Apis mellifera) are arguably the most important insect pollinators of major agricultural crops around the world. Therefore, it is important to assess the health of managed honey bees in every region, particularly in areas where this information remains unknown. In 2015 and 2016, several managed apiaries were surveyed on the Caribbean Island of Dominica, West Indies. We measured the levels of the ectoparasitic mite, Varroa destructor, and analyzed the levels of Nosema apis and Nosema ceranae using spore counts and qPCR. Colonies sampled in 2015 were also analyzed for subspecies composition using mitochondrial DNA. Varroa levels were low overall (1-7 mites per 100 bees), with many colonies exhibiting no mites. In apiaries where varroa counts were performed in both years, there were significantly more mites in 2016 than in 2015. Overall, colonies exhibited low Nosema spp. spore counts, with only 1.33% of the bees analyzed scoring positive for spores. qPCR revealed that of the 30 colonies analyzed, all but six (82.3% of the total) were infected with low levels of N. apis. The prevalence of N. ceranae infection was higher, with 97.1% of the bees analyzed being infected. The majority of colonies analyzed (84.4%) exhibited the M4 haplotype (A. m. mellifera), while the remaining (15.6%) exhibited the C1 haplotype (A. m. ligustica). We did not find any colonies that had the African A. m. scutellata haplotype. This study is the first survey conducted to assess the genetic structure and health status of managed honey bees in Dominica.