Link to paper: https://onlinelibrary.wiley.com/doi/10.1111/mec.15080

The parasitic mite Varroa destructor can devastate honey bee (Apis mellifera) populations by reproducing in the pupal cells where young bees develop. Without human intervention, this typically leads to the death of the honey bee colony. Some colonies, however, are able to resist Varroa by inhibiting it’s reproduction. To further our understanding of the relationship between the honey bee host and its parasite, we studied one of these colonies where half of the male (drone) pupae exhibited resistance to Varroa.

By screening the genomes of resistant and susceptible pupae from this colony, we identified a resistance-linked gene in the ecdysone pathway. Ecdysone is a hormone which honey bees produce during pupation. Due to its fascinating dependency on the honey bees, Varroa requires this hormone to reproduce, but lacks the ability to produce this hormone itself. This raises the possibility that Varroa is co-opting host hormones to time and initiate its own reproduction. Thus, changes in this pathway could prevent Varroa from reproducing. These results highlight the close links between host and parasite and could provide new avenues for Varroa control in honey bees.

Conlon, B. H., Aurori, A., Giurgiu, A. I., Kefuss, J., Dezmirean, D. S., Moritz, R. F., & Routtu, J. (2019). A gene for resistance to the Varroa mite (Acari) in honey bee (Apis mellifera) pupae. Molecular Ecology. 2019. 28-12. 2958-2966