Retracing the routes of invasion and evolutionary paths of the honey bee mite using genomic

• Project/Area Number: 19F19723
• Research Category: Grant-in-Aid for JSPS Fellows
• Allocation Type: Single-year Grants
• Section: 外国
• Review Section: Basic Section 45020:Evolutionary biology-related
• Research Institution: Okinawa Institute of Science and Technology Graduate University
• Principal Investigator: ミケェエヴ アレクサンダー 沖縄科学技術大学院大学, 生態・進化学ユニット, 准教授 (90601162)
• Co-Investigator(Kenkyū-buntansha): TECHER MAEVA 沖縄科学技術大学院大学, 生態・進化学ユニット, 外国人特別研究員
• Project Period (FY): 2019-07-24 – 2021-03-31
• Project Status: Completed (Fiscal Year 2020)
• Budget Amount: ¥1,200,000 (Direct Cost: ¥1,200,000); Fiscal Year 2020: ¥200,000 (Direct Cost: ¥200,000); Fiscal Year 2019: ¥1,000,000 (Direct Cost: ¥1,000,000)
• Keywords: Parasite / Invasion / Coevolution / Varroa / Honey bee / Population genomics / Whole-genome sequencing / parasites / mites / viruses / honey bees / coevolution

Outline of Research at the Start

As first of its kind, I plan to do population genomics of V. destructor at a global scale by sequencing the whole genome of 500 mites. The project is based on my previous results: i) the new reference V. destructor genome, ii) genomics pipeline used in Asian populations and iii) the so far largest Varroa mite world collection (< 800 samples from five continents) achieved in the proposed host Ecology and Evolution lab. I will be sequencing the whole genome of mites from native and invasive areas from all continents, different host populations and mite phenotypes.

Outline of Annual Research Achievements

Since 2016, we initiated a Varroa world collection that was large of 878 samples from 31 countries. During the fellowship, we succeeded in increasing its size and coverage by developing new international collaborations with now 1659 samples from 60 countries. We unearthed i) 106 historical samples collected during V. destructor early spread between 1989 to 2000 and ii) all Varroa species, including undescribed ones. Using our reference genome of V. destructor (Vdes3.0) and state-of-the-art genomic tools, we successfully sequenced the whole genome of 1760 samples worldwide.

By focusing on the native range, where the parasites exist in sympatry on a novel and original host, we found that host switches put the parasites on the path to speciation but that each switch requires considerable genetic diversity to take hold. We were able to reconstruct the origin of host switches and pin-point new ones with congruent and independent analysis. This is in stark contrast to the long-held view that Varroa is quasi-clonal on the novel host and explains its remarkable adaptability to different host races and human countermeasures.

We then studied the world biogeography of the invasive V. destructor using spatial and temporal population genomics. We were able to show that key elements to Varroa’s success were due to unreported host switch events and multiple invasion pathways which promoted hybridization. By looking at different population levels (from host colony to continents), we further elucidate the origin and evolution of V. destructor on its new host.

Research Progress Status

令和2年度が最終年度であるため、記入しない。

Strategy for Future Research Activity

令和2年度が最終年度であるため、記入しない。

Research Products

• [Journal Article] Varroa destructor: A Complex Parasite, Crippling Honey Bees Worldwide (2020)
  • Author(s): Traynor, K. S., Mondet, F., de Miranda, J. R., Techer, M., Kowallik, V., Oddie, M. A. Y., Chantawannakul, P., McAfee, A.
  • Journal Title: Trends in Parasitology Volume: 36 Issue: 7 Pages: 592-606
  • DOI: 10.1016/j.pt.2020.04.004
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Journal Article] When European meets African honeybees (Apis mellifera L.) in the tropics: Morphological changes related to genetics in Mauritius Island (South-West Indian Ocean) (2020)
  • Author(s): Galataud, J., Delatte, H., Techer, M. A., Simiand, C., Sookar, P., Reynaud, B., Clmencet, J.
  • Journal Title: PloS One Volume: - Issue: 11 Pages: e0242053-e0242053
  • DOI: 10.1371/journal.pone.0242053
  • Peer Reviewed / Open Access / Int'l Joint Research
• [Presentation] Facing the War between Honey Bee and Mites: Genomic Insights into Varroa Global Success (2020)
  • Author(s): Maeva Techer
  • Organizer: 28th Plant and Animal Genome Conference (PAG XXVIII)
  • Int'l Joint Research / Invited
• [Presentation] World biogeography and population genomics of ectoparasitic Varroa mites (2020)
  • Author(s): Maeva Techer
  • Organizer: COLOSS (Prevention of honey bee Colony LOSSes) Asia Conference 2020
  • Int'l Joint Research / Invited
• [Presentation] Facing the War between Honey Bee and Mites: Genomic Insights into Varroa Global Success (2020)
  • Author(s): Maeva Techer
  • Organizer: Plant and Animal Genomics conference
• [Remarks] Creation of an interactive map
  • URL: https://maevatecher.github.io/varroa-mtDNA-world-distrib/