Dominant honeybee colony infestation by Varroa destructor (Acari: Varroidae) K haplotype in Japan

Varroa destructor Anderson and Trueman (Acari: Varroidae) are ectoparasitic mites found in the western honeybee Apis mellifera Linnaeus (Hymenoptera: Apidae). Varroa destructor is classified into two haplotypes, i.e., Korea (K) and Japan (J), based on mtDNA sequences. Among these, V . destructor K haplotype is possibly a more severe threat to A . mellifera colonies. Previous studies collected both V . destructor haplotypes from honeybee colonies in Japan. However, no detailed surveillance of infestation of Japanese apiaries by V . destructor or identification of their genetic structure has been conducted to date. We surveyed V . destructor at 15 different Japanese apiaries of A . mellifera . Varroa destructor was collected from 14 Japanese apiaries, and all mites were classified as V . destructor K haplotype. Varroa destructor infestation of the Japanese honeybee A . cerana japonica Radoszkawsi (Hymenoptera: Apidae) was also analyzed. Varroa destructor K haplotype was predominant in A . cerana colonies. Despite the different host species, all collected V . destructor K haplotype samples were classified into a single haplogroup, i.e., K1-1/K1-2. These results indicate that A . mellifera and A . cerana were infested by the same V . destructor haplogroup. This is the first report detailing a survey on V . destructor prevalence and haplogroups among Japanese apiaries.