Where did the Varroa mite originate? - briefly
The Varroa destructor mite originated in Asia, most likely in the native range of the eastern honey bee (Apis cerana) across Southeast Asian countries such as Vietnam and Thailand. It subsequently expanded to Western honey bee (Apis mellifera) populations worldwide.
Where did the Varroa mite originate? - in detail
The mite Varroa destructor originates in eastern Asia, where it co‑evolved with the eastern honeybee Apis cerana. Genetic analyses of mitochondrial DNA trace the earliest lineages to regions that include the Korean Peninsula, China, and Japan. In its native host, the parasite causes limited mortality because A. cerana has developed behavioral and physiological defenses.
The first documented appearance on the western honeybee Apis mellifera occurred in Japan in 1904, when beekeepers reported abnormal colony losses after the introduction of Asian bees. Subsequent spread followed major movements of bee colonies:
- 1950s‑1960s: introduction of A. cerana colonies into Europe for breeding, bringing the mite into the continent.
- 1970s: detection in the United Kingdom and Italy, linked to imported queen stock.
- 1980s‑1990s: rapid expansion across North America, Australia, and South America through commercial bee trade.
- 2000s‑present: global presence, with occasional re‑introductions of Asian genotypes that increase genetic diversity of the parasite.
Morphological studies indicate that the original Asian populations possessed a shorter dorsal shield and fewer setae than the later European strains, reflecting adaptation to the new host. Phylogeographic surveys show two major haplotypes—Korean and Japanese—both derived from the same ancestral population in eastern Asia.
Ecological factors that facilitated the transition include:
- High density of managed colonies in temperate regions, providing abundant hosts.
- Lack of innate grooming behavior in A. mellifera that is present in A. cerana.
- Human‑mediated transport of brood frames, queens, and packaged bees.
Current research confirms that the Varroa mite’s Asian origin remains the source of genetic variation that underlies its worldwide invasiveness. Control strategies therefore focus on breeding A. mellifera lines that mimic the defensive traits of its eastern counterpart and on restricting the movement of live bee material across borders.