Tsen Hua
Department of Entomology, National Chung Hsing University, Taichung 402, Taiwan
Department of Plant Medicine, National Pingtung University of Science and Technology, Pingtung 912, Taiwan.
Panuwan Chantawannakul
Department of Biology, Faculty of Science, Chiang Mai University, Chiang Mai, Thailand
Research Center of Microbial Diversity and Sustainable Utilization, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand.
Cheng-Lung Tsai
Department of Entomology, National Chung Hsing University, Taichung 402, Taiwan
Department of Entomology and Nematology, Ft. Lauderdale Research & Education Center, University of Florida, Ft. Lauderdale, FL 33314, USA.
Wen-Bin Yeh
Department of Entomology, National Chung Hsing University, Taichung 402, Taiwan.
Communicated by Benny Kwok Kan Chan
The Modern beekeeping industry is being challenged by the varroan mite and its transmitted pathogens. Various types of Varroa destructor exhibit different levels of virulence toward honey bees, but only the Japanese (J) and Russian (R) types were found to infect Apis mellifera. Type R was more highly virulent against A. mellifera in comparison with type J. Examining the genetic profile of Varroa species is therefore of crucial importance in apiary management. In this study, maternally inherited mitochondrial cytochrome oxidase I (COI) and bisexual nuclear internal transcribed spacer (ITS) sequences of V. destructor individuals from Taiwan were determined. All 168 COI sequences observed in populations obtained from A. mellifera were identical and belonged to type J, with one base difference to that of populations collected from A. cerana; the new type is named ‘T type’ (Taiwan type). ITS sequences of V. destructor and its sister species V. jacobsoni were identical. A network analysis based on 611 COI sequences compiled from references indicated the presence of 27 haplotypes in V. destructor. Epidemic history and relationship analyses of V. destructor showed that the basal haplotypes were those from A. cerana and many R-extending haplotypes infesting A. mellifera involving amino acid substitutions. Calibration dating based on COI analysis revealed that V. destructor differentiated from its sibling lineage (occurring in Sri Lanka) prior to 1.3 million years ago (Mya). The ancestral haplotype retention and drift in V. destructor that occurred locally during 0.10–0.64 Mya might be relevant to its host A. cerana, which had been isolated geologically. The highly virulent type R was spreading quickly and could gradually outcompete the common and less virulent type J. Type T, being intermediate between types R and J, ought to be studied to better understand the pathogenic mechanism of V. destructor in A. mellifera. Moreover, for areas where type R does not occur, such as Taiwan, quarantine requirements are crucial for reducing invasion risks.
Supplementary materials
Collection localities of
Varroa destructor from apiaries in Taiwan Island. All mites were collected from host
Apis mellifera except the Xinshe samples parasites in
Apis cerana. The Central Mountain Range is shown, with the light gray representing the altitude between 1,000 m and 2000 m.
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The
COI sequences of
Varroa destructor analyzed in this study. Pertinent information for each sequence was shown including the description with accession number (or relevant extending accession number,
i.e., sequence identical to the accession number defined by authors), haplotype name (or individual’s abbreviation), the relevant parasite host (Acer:
Apis cerana; Amel:
Apis mellifera), acquired locality, and the cited reference. Pertinent information and order of sequences were also shown in table S2.
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Bayesian phylogenetic inference for
COI sequences of
Varroa destructor haplotypes using outgroups of
Varroa jacobsoni and the Luzon varroans. Posterior possibilities are shown beneath the nodes. Haplotypes from the parasite host of
A. cerana are labeled in italic and those from
A. mellifera are labeled in accession number with its acquired country.
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Pertinent collection information of
Varroa destructor from Taiwan, Thailand, and China.
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Haplotype information of
COI sequences of
Varroa destructor analyzed in this study, including haplotype abbreviation and their relevant sequences number, haplotype name, accession number, acquired country with its individuals, parasite host, and the cited references.
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