Genetic Secret of Varroa Mite, Threat to Honeybees, Revealed
Translated & summarized from Ynet by baba
An international study led by the University of Haifa has discovered that male Varroa mites are genetic clones of their mothers, carrying and expressing both copies of their mother's genome. This finding challenges previous scientific understanding and helps explain the mite's high adaptability and pesticide resistance. The research tracked mite families over three generations and used mathematical modeling to assess the impact on genetic diversity. This discovery necessitates updating models used to combat the mite, a major threat to honeybees worldwide.
The story in 5 lines · by baba
- Male Varroa mites are genetic clones of their mothers, carrying both copies of the maternal genome.
- This reproductive mechanism helps the mite maintain adaptability and pesticide resistance.
- The discovery challenges decades of scientific understanding about Varroa mite genetics.
- Research involved tracking 30 mite families over three generations and genome sequencing.
- Updated models are needed to predict Varroa mite resistance to pesticides and breeding efforts.
An international research effort, led by the University of Haifa and the Migal Research Institute, has uncovered a novel reproductive mechanism in the Varroa destructor mite, a major threat to honeybees. The study, published in Nature Communications, reveals that male mites are genetic clones of their mothers, carrying and expressing both copies of their mother's genome. This finding challenges the long-held scientific belief that male mites possessed only a single copy of each chromosome.
Dr. Nurit Eliash of the University of Haifa and Migal Research Institute, who spearheaded the research, explained that this unique genetic process helps the mite maintain high adaptability and resistance to pesticides. "Varroa mites primarily reproduce among brothers and sisters, and new populations start from a small number of mites," she stated. "Therefore, we would expect it to quickly lose its genetic diversity. The way genes are passed down through generations, as we discovered in the study, slows this process and may explain how the parasite maintains its high adaptability and resistance to pesticides."
The Varroa mite feeds on honeybees and reproduces within the sealed brood cells where young bees develop, transmitting deadly viruses that cause bee mortality. Originally a parasite of the Eastern honeybee (Apis cerana), it later transferred to the Western honeybee (Apis mellifera) and spread globally.
Researchers tracked 30 mite families over three generations, analyzing 223 mites. They sequenced their genomes and examined gene expression, confirming that male mites inherit and express both of their mother's genetic copies. A mathematical model based on these findings indicates that this reproductive strategy slows the loss of genetic diversity compared to previous assumptions, particularly when the mite colonizes a new bee population.
Dr. Eliash noted that current models for predicting the mite's response to pesticides and breeding resistant bees are based on the outdated assumption of single-copy male genomes. "It turns out that this starting point needs to be updated," she concluded. While the study does not offer an immediate treatment, it could improve future predictions of how Varroa mite resistance develops.