Impact of the phoretic phase on reproduction and damage caused by Varroa destructor to the European Honey Bee. raw_data.xlsx

We
investigated if the type of bees on which Varroa
stays during the phoretic phase and if the duration of this stay influenced the
reproductive success of the parasite and the damage caused to bees. For that
purpose, we used an in vitro rearing
method developed in our laboratory to assess egg laying rate and the presence
and number of fully molted daughters. The expression level of two Varroa vitellogenin genes (VdVg1 and
VdVg2), known to vary throughout reproduction, was also quantified. Results
showed that the status of the bees or time spent during the phoretic phase
impacts neither reproduction parameters nor the Varroa vitellogenin genes levels of expression. However, we
correlated these parameters to the gene expression and demonstrated that
daughters expressed the vitellogenin genes at lower levels than their mother.
Regarding the damage to bees, the data indicated that a longer stay on adult
bees during the phoretic phase resulted in more frequent physical deformity in
newborn bees. We showed that those mites carry more viral loads of the Deformed
Wing Virus and hence trigger more frequently overt infections. This study
provides new perspectives towards a better understanding of the Varroa-honeybee interactions.