Resistance to the Parasitic Mite Varroa destructor in Honey Bees form Far-Eastern Russia

Varroa destructor is a parasitic mite of the Asian honey bee Apis cerana.  Owing to host range expansion, it now plagues Apis mellifera, the world's principal crop pollinator and honey producer.  Evidence from A. mellifera in far-eastern Russia, Primorsky (P) originating from honey bees imported in the mid 1800's, suggested that many colonies were resistant to V. destructor.  A controlled field study of the development of populations of  V. destructor shows that (P) colonies have a strong, genetically based resistance to the parasite.   As control colonies (D) were dying with infestations of ~ 10,000 mites, (P) colonies were surviving with infestations ~ 4,000 mites.  Several characteristics of the (P) bees contributed to suppressing the number of mites parasitizing their colonies.

Figure 1. Average V. destructor infestations (numbers of adult female mites) in Primorsky (black bars)and domestic colonies (white bars) through time. Error bars = sem.

Figure 2.  Box plots of total adult bees, total drone brood, total worker brood, and brood to adult bee ratios for Primorsky (P) and domestic (D) colonies for months from July 1998 through July 1999. |= median observation, filled O = range between 1st and 3rd quartile, box [ ] = range, O = outlying observation.

Figure 3.Pie charts showing the proportional distribution of adult female mites in Primorsky (P)and domestic (D) colonies through time.Black: phoretic mites on adult bees/total mites,White: mites infesting worker brood/total mites,Gray: mites infesting drone brood/total mites. Colony numbers are shown for each period and stock.

Month to month mite population growths. Numbers less than 1 indicate population declines.

Overall, Primorsky (P) honey bees appear to have several mechanisms which act in concert to provide them with substantial resistance to V. destructor.  It is unlikely that we have yet identified all of the factors that may contribute to this resistance.  Indeed, a substantial number of hypothesis remain wholly or partially untested.  However, the the diversity of traits identified in this study that may contribute to the resistance suggests that a constellation of traits and genes underlie the overall resistance and provide opportunities for further development of the resistance through selective breeding.

Reference to the full article:

T. E. RINDERER, L. I. DE GUZMAN, G. T. DELATTE, J. A. STELZER, V. A. LANCASTER, V. KUZNETSOV, L. BEAMAN, R. WATTS, J. W. HARRIS.  Resistance to the parasitic mite Varroa destructor in honey bees from far-eastern Russia.  Apidologie 32 (2001) 381-394.