Submitted to: Experimental and Applied Acarology
Publication Type: Peer reviewed journal
Publication Acceptance Date: 6/8/2012
Publication Date: 7/3/2012
Citation: Kirrane, M.J., De Guzman, L.I., Rinderer, T.E., Frake, A.M., Wagnitz, J., Whelan, P.M. 2012. Age and reproductive status of adult Varroa mites affect grooming success of honey bees.. Experimental and Applied Acarology. 58(4):423-430. Interpretive Summary: Grooming behaviour is difficult to measure due to the lack of reliable measurement tools. Existing grooming bioassays may be improved by using mites with an optimum age and reproductive status. This bioassay evaluated the response of bees to different classes of mites: gravid, phoretic foundresses, phoretic daughters and a combination of gravid and phoretic foundress mites. Plastic cages containing about 200 bees were inoculated with 20 mites each. We found that about ½ of the introduced phoretic daughter mites were groomed during the first day of inoculation. In contrast, the bees inoculated with phoretic foundresses and the combination of gravid and phoretic foundress mites only removed nearly 1/3 of the introduced mites. Bioassays that include daughter mites which are removed from the nest may reveal a more concrete contribution of grooming to the overall resistance of bees to varroa mites.
Technical Abstract: This study evaluated for the first time the grooming response of honey bees to different ages and reproductive statuses of varroa mites in the laboratory. Plastic cages containing a section of dark comb and about 200 bees were inoculated with groups of four different classes of mites: gravid, phoretic foundresses, phoretic daughters and a combination of gravid and phoretic foundress mites. Each cage received 20 mites belonging to one of these classes. Our results showed that one day after mite inoculation, phoretic daughter mites were the most prone to grooming by honey bees with an average mite drop of 49.8 ± 2.6%. The lowest mite drop was recorded for bees inoculated with phoretic foundresses (mean = 30.3 ± 3.6%) but was comparable to bees inoculated with gravid mites (mean = 31.8 ± 3.8%) and the combination of gravid and phoretic foundress mites (mean = 34.2 ± 3.2%). No differences among mite types were detected during the second and third days of observation. Regardless of mite type, the highest mite drop was recorded on the first day (35 ± 2.1%) compared to the drop for any subsequent day (less than 10%). Because of the great reproductive potential of daughter mites, their inclusion in assessing grooming behaviour may increase insight about the importance of grooming in mite resistance.