| Tropilaelaps mites are an economically important pest of honeybee throughout Asia. We have surveyed the species composition of the mites firstly. Based on this, we have a national epidemiological survey on the the infestation rates, intensity of the mites and its associated factors in Apis mellifera. According to the risk factors, as suggested by the epidemiological survey, some parasitologies of the mites were studied furtherly, as parasitologies were useful supplements for the epidemiological survey. The main results of the study are as follow:1. Study of species composition of Tropilaelaps mites: The morphology, mitochondrial DNA (mtDNA) CO-â… and ribosomal ITS1-5.8S-ITS2 fragments of Tropilaelaps mites were surveyed for sequence variation or the presence or absence of specific restriction sites that differentiate four species of Tropilaelaps mite. Based on these identified diagnostic characters, all samples in this study corresponded to T. mercedesae, which has been mistaken for T. clareae until now. None of the other Tropilaelaps species were found infesting A. mellifera in China.2. Epidemiological survey on T. mercedesae in A. mellifera in China: The infestation rates, intensity of T. mercedesae and its associated factors such as climate, district, management practices, operation size,and beekeeper characteristics were included in the survey. The results showed that geographical location, season, royal jelly collection and Varroa infestation were the factors that influence the intensity of T. mercedesae. The highest infestation rate of T. mercedesae was encountered in autumn, followed by summer, and then spring and winter; the infestation rates and intensity of T. mercedesae in the central and south were higher than in the north; colonies with a high level of Varroa infestation or colonies that had be used for royal jelly collecting tended to show high levels of T. mercedesae.3. Methods of rearing Tropilaelaps mites and V. destructor to the adult stage in the laboratory and its reproductive biology. Newly sealed worker broods were inoculated with mites and cultured in the constant temperature incubator. In this method, high survival rates for both mites and hosts were seen, and numbers of daughter mites were harvested. Based on this, the reproductive biology of T. mercedesae and V. destructor were studied. The results showed that the numbers of offspring for both mites were reduced when they were raised by mixed-species pairs, indicating that there was an apparently mutual interference between V. destructor and T. mercedesae when they breeded in one cell.4.The infestation rates of V. destructor and T. mercedesae for sealed worker broods: The results showed that the infestation rates varied in different months and even in different years for both mites when they were co-infested in one colony, and the infestation rates of V. destructor was significantly higher than T. mercedesae.5. The parasitic features and infestation rates of V. destructor and T. mercedesae on adult worker bees: The results indicated that the hide place on adult worker bees for both mites was different when they were co-infested in one colony. The infestation rates of V. destructor varied with months and bee brood quantities, but adult bees were not prefered by T. mercedesae. The results also showed that if there were enough larve, both V. destructor and T. mercedesae prefer larve to adult bee, and the infestation rates of V. destructor on adlut workers were significantly higher than T. mercedesae.6. The colony's infestation level of V. destructor and T. mercedesae and its effects on the population quantity of honey bee: The method of 'sticky board'was used in this study to inspect the infestation level of both V. destructor and T. mercedesae when they were co-infested in one colony. The results showed that the infestation levels of V. destructor were significantly higher than T. mercedesae, indicating that V. destructor was more dangerous to A. melllifera than T. mercedesae in the experimental condition,and the conclution was in line with the infestation rates for sealed worker broods and adult worker bee. The results also showed that the variation of population quantity of honey bee in the Apistan treated and untreated colonies was not obvious in the first two month, but a significant decline in the untreated colonies after 4 month, and all bees died in the untreated colonies after 8 month.7. Based on the morphological and molecular traits, the mites from house flies, field mousse and heat preservation materials were not Tropilaelaps mites, and white mouse is not an intermediate host of Tropilaelaps mites also.The results of the present study clarified the taxonomic status and biogeography of Tropilaelaps mites in China, provided factors that influence the infestation rates and intensity of T. mercedesae, and preliminarily revealed the biology characteristics of T. mercedesae and V. destructor when they were coinfested in one colony. These results should have implications for control and bee quarantine efforts in China.
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