59-05-032 Proceeding

369 Proceedings of the Princess Maha Chakri Sirindhorn Congress colony No. of reproductive mites No. of progeny produced by a reproductive mite 1 2 3 15 12 9 3 - 16 5 5 - - 17 7 7 - - 18 7 6 1 - 19 4 3 - 1 20 6 4 2 - 21 16 8 7 1 Total (%) 198 142 (71.7) 48 (24.2) 8 (4.1) Discussion The T.mercedesae in the colonieswe studiedhad a high rate ofmultiple infestation. However, multiple infestations had quite similar rates of reproduction per foundress when compared to the rates found in cells having only one reproductive foundress mite. Evidently the reproductive rate is not influenced to any great degree by numbers of foundresses. Since the reproductive rates are similar, we infer that the rate of non-reproductive foundresses in multiply infested cells is much lower than we observed for cells having only one foundress. It may be that multiple infestations are necessary for mating, outcrossing etc. It is unusual that a honey bee parasitic mite infesting its native host has a very high rate of non-reproduction. In A. cerana , Tewarson et al. (1992) found that almost all V. jacobsoni mites reproduced on drone brood they examined during the season favorable for drone brood production. This is the first report of a high rate of non-reproduction in a native host of a parasitic mite. Hence, it is a mechanism of resistance to the mite employed by a native host at least on A. dorsata . Or-maybe it is not common. If it is common, then thinking of non-reproduction as a resistancemechanismgenerallymakes sense. If it is not common, then themost resistant of honey bees to the various mites, ie. the native hosts, are not using non-reproduction. Mite non-reproduction is a genetic trait of bees (Harris andHarbo, 2001) and one of many resistant mechanisms of honeybees tomites (Buchler andDrescher, 1990; Boecking andDrescher, 1993). Mite growthwas low in colonies with the high percentage of non-reproductivemites (Harris and Harbo, 2001). In this study, the average percentage of non-reproductive mites on Pdl and older worker pupae from A. dorsata colonies (64.4%) was higher than that of A. mellifera colonies (7 - 27%) from the previouus reports by Ritter and Scheider-Ritter (1988) andWoyke (1990), but lower than non-reproductive rates (76.8 - 92.8%) in Thai A. mellifera colonies from the recent report by Khongphinitbunjong et al. (2014). This suggests that A. dorsata had resistant genetic trait to T. mercedesae . T. mercedesae is a natural brood parasite but not considered to be a serious pest of A. dorsata (Wongsiri et al., 1989). A. dorsata and T. mercedesae can coexist for long time