59-05-032 Proceeding

365 Proceedings of the Princess Maha Chakri Sirindhorn Congress Kavinseksan, 2003; Khongphinitbunjong et al., 2014). This is especially true in studies of A. mellifera infested by Varroa destructor. Non-reproduction of mites is a mite-bee interaction in colonies in which mites show impaired reproductive ability (Anderson, 1994). The causes of non- reproduction by foundress mites is unknown. However, Harbo and Harris (1999, 2001) reported that a heritable genetic characteristic of bees causedmites to become non-reproductive. Chemicals from the haemolymph of larva and prepupa stimulate Varroa mites to produce and lay eggs (Harris and Harbo, 2001). Several researchers have studied the role of juvenile hormone as a trigger for Varroa mite reproduction. Exogenous application of juvenile hormone to bee larvae increased the reproductive rate of Varroa mites (Hanel, 1983, 1986; Hanel and Koeniger, 1986). However, endogenous juvenile hormone titers are similar in bee larvae from races and species of bees that differ dramatically in their abilities to support mite reproduction (Rosenkranz et al., 1989, 1993). Woyke (1989) reported that the thickness of T. mercedesae females (when referred to as T. clareae ) in brood cells after cell sealing 48 to 96 h increased to be double that of mites moving freely on the combs because they feed and become engorged on haemolymph. Hence, it is possible that some substances in bee’s haemolymph may also affect the reproduction of T. mercedesae. Additionally, other factors may also result in non-reproduction by infesting T. mercedesae. Some studies of non-reproduction by T. mercedesae infesting A. mellifera have been reported. Non- reproduction of T. mercedesae in A. mellifera colonies was 18.3% inVietnam, 7.3% in Afghanistan (Woyke, 1990) and 27 - 92.8% inThailand (Ritter and Schneider-Ritter, 1988; Khongphinitbunjong et al., 2014). In each of these studies, non-reproductionwas being evaluated as a possiblemechanism of resistance by A. mellifera to T. mercedesae . We hypothesized that if non-reproduction to T. mercedesae was an important mechanism of resistance to T. mercedesae , it would be prominent among T. mercedesae foundresses infesting A. dorsata . To test this hypothesis, brood cells of A. dorsata colonies were surveyed for rates of reproducing and non-reproducing foundress mites. In addition, rates of fecundity for reproducing mites were determined. Materials and Methods Twenty-one A. dorsata brood combs were collected from many different locations in Thailand between March 2014 and February 2015. Eight combs were collected in Northern (Chiang Rai, Chiang Mai, Lamphun, Mae Hong Son, Phayao, Phrae and Lampang), five combs in Northeastern (Nong Khai, Udon Thani, Ubon Ratchathani and Nakhon Ratchasima), six combs in Central (Kanchanaburi, Lop Buri, Nakhon Nayok, Samut Songkhram and Ratchaburi) and two combs in Southern (Chumphon and Phuket). The entire brood combs were cut from these brood nests immediately frozen for later examination. Freezing allowed for the transport of the brood to a laboratory for examination. More importantly, adult T. mercedesae , unlike adult V. destructor , run from opened cells very quickly, making it impossible to count them accurately or evaluate their sex or state of maturity. The frozen capped brood of the harvested nests was later thawed, and cells that contained a pupa which was at least sufficiently mature to have dark brown eyes and a lightly pigmented