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Becky Masterman earned a PhD in entomology at the University of Minnesota and is currently a host for the Beekeeping Today Podcast. Bridget Mendel joined the Bee Squad in 2013 and led the program from 2020 to 2023. Bridget holds a B.A. from Northwestern University and an M.F.A. from the University of Minnesota. Photos of Becky (left) and Bridget (right) looking for their respective hives. If you would like to contact the authors about virus stories, please send an email to mindingyourbeesandcues@gmail.com.
Minding Your Bees and Cues
Varroa vs. World: Winter Games Edition
By: Becky Masterman & Bridget Mendel
Next year’s Beekeeping season is still in the future, untouched by the realities and limitations of timing, weather, blooms, bees, and their pests. There’s still time to mend equipment, to plot and plan for the most perfect beekeeping season. To help, we’ve done a scan of new bee-varroa news, looking for science-grounded clues for how to best approach management this season. And we’re going to try to make a game of it.
Is it ruining games or making varroa fun to combine the two?
Varroa – 1 Honey Bees – 0
In one study, 45 colonies were observed from June to October 2024, and three different natural selection breeder categories were compared (Akongte et al., 2026). The different groups included: 1) 12 hygienic and low grooming colonies; 2) 20 non-hygienic and high grooming colonies; and 3) 13 intermediate hygienic and grooming colonies.
Researchers observed that higher colony varroa infestations were related to higher protein content in pollen collected by foragers suggesting that colonies were compensating for the impact of parasitism using nutrition (Hilsmann et al., 2025). Photo credit: Rebecca Masterman
The devastating but not-surprising results showed that by the end of the 5-month study, all of the groups suffered high losses. In Group 1, there were no surviving colonies. Group 2 had approximately 30% of the colonies alive and in Group 3, less than 10% percent of colonies survived. All groups were confirmed to have deformed wing virus (DWV). Colonies from Groups 1 and 3 also tested positive for Acute Bee Paralysis Virus (ABPV) and Israeli Acute Paralysis Virus (IAPV). The researchers found interest in the higher survival rate of the non-hygienic, high grooming colonies.
We are respectfully curious just how long the surviving colonies survived.
Honey bees – 1 Beekeeper – 0
A laboratory study performed on individual worker bees compared the sting response threshold of Varroa destructor-parasitized-bees compared to non-parasitized bees (De la Mora et al., (2024). The parasitized bees stung faster when provoked. We’re sympathetic: who wouldn’t sting faster if already in a bad mood carrying around a giant, vitality-sucking arachnid?
Researchers demonstrated that being fed upon by varroa lowered the sting response threshold of individual workers. The authors suggest that the change in the sting response threshold of parasitized bees results in an increased colony level defensive behavior, improving the parasitized colonies ability to defend themselves against predators.
Our takeaway: listen to your bees. If they greet you with more stings than usual, do a quick alcohol wash to test for heightened varroa levels.
Raspberry Pi camera + Beekeeper – 1 Varroa – 0
In another study of colonies not treated for varroa infestations, all colonies were confirmed to have deformed wing virus (Akongte et al., 2026). While some infected workers will have deformed wings, workers can also be asymptomatic for this sign. Photo credit: Rebecca Masterman
Don’t like doing alcohol washes? Neither do a group of researchers who are trying to bring back the Raspberry Pi. Remember Raspberry Pi? Think small, affordable computer with a camera. Well, we actually haven’t asked them how they feel about sampling for varroa, but something is motivating a number of research teams to improve on jarless varroa detection technology. New sampling technologies will use cameras to search for varroa on the mites. One recent report by Su et al. (2026) states, “By reducing reliance on manual inspections, the proposed approach provides a practical, low-cost, and scalable solution for early pest detection and sustainable colony health management.” We applaud these efforts and look forward to this technology being a part of colony care.
Varroa – 1 Honey Bees – ?
You are all familiar with the saying, “Ask a beekeeper how to control varroa effectively and watch them break out into a nervous sweat.” A research team in Germany led an innovative study comparing two different types of varroa management and the impacts on the honey bees (Hillsman et al., 2025). They called one method Conventional and it included: regular drone brood removal in the mating system, formic acid treatment in the Summer and oxalic acid in the Winter. The other method was Innovative and included no drone brood removal, a Summer brood break followed by an oxalic acid treatment and a possible Winter oxalic acid treatment depending on mite drop counts exceeding their threshold. They reported significantly higher varroa infestations in the Innovative treatment group. While there was no reported difference in honey production, they did report that the Innovative treatment colonies foraged for higher protein source pollen, possibly to offset the impact of the parasite levels.
The bees in the Innovative management regimen group also had significantly higher levels of juvenile hormone III in their hemolymph. This hormone is important in the control of age-related behavioral tasks in a colony. While no mention of colony survival was mentioned, this was a multi-year study.
Our takeaways (and admit it, some of yours too!):
1. The Conventional treatment regimen is not aggressive enough for varroa control in our apiaries.
2. It is alarming to note that based on the status of varroa in your colonies, their hormones are impacted by higher infestations, and they might be increasing their protein foraging efforts to offset the impact of varroa.
3. It would be interesting to compare other treatment regimens to see the potential impact of infestation in honey production and survival in relation to the physiological and behavior changes reported in the study.
Varroa – 0 Beekeeper – 1 Honey Bee – 1 Formic Acid – 1
Some of us depend on using a formic acid treatment in our colonies to manage the mite population. It has been a reliable source of mite control and depending on how and when you use it, it is good for the colony and queen issues are not a major concern. While we understand that some beekeepers have had issues with using formic acid to control varroa, we have a few tips: 1. Follow all instructions provided by the manufacturer including temperature ranges, colony size, and placement. 2. Understand that a heavily varroa infested and diseased colony is not going to be able to tolerate and respond to a formic acid treatment well. Formic acid will not cure a colony with parasitic mite syndrome.
The good news for those of us who use formic acid as part of our mite management plans is that a review of the literature (Kosch et al., 2025) has reported no evidence of resistance to formic acid control of varroa. While they recommend that beekeepers and researchers stay vigilant (beekeepers – keep rotating control methods! Researchers – keep looking for signs of resistance!), we can start this year knowing that varroa infestations are still a threat to colonies thriving and surviving and formic acid is still a threat to varroa thriving and surviving, too.
References
Akongte, P. N., Oh, D., Jin-Myung, K., Lee, C., Choi, Y.-S., & Kim, D. (2026). Survival mechanisms of preselected breeder honeybee (Apis mellifera) colonies under Varroa-infestation: Selective breeding of natural selection. Journal of Invertebrate Pathology, 214, Article 108466. https://doi.org/10.1016/j.jip.2025.108466
De la Mora, A., Morfin, N., Espinosa-Montaño, L. G., Medina-Flores, C. A., & Guzman-Novoa, E. (2024). The mite Varroa destructor lowers the stinging response threshold of honey bees (Apis mellifera). Journal of Apicultural Research, 63(1), 184–188. https://doi.org/10.1080/00218839.2021.1959754
Hilsmann, L., Krischke, M., Mueller, M. J., Manzer, S., & Scheiner, R. (2025). Balancing Varroa management and honey bee resilience: Behavioral and physiological consequences of temporarily high mite pressure. International Journal for Parasitology. Parasites and Wildlife, 28, Article 101137. https://doi.org/10.1016/j.ijppaw.2025.101137
Kosch, Y., Muelling, C., & Emmerich, I. U. (2025). Assessment of Resistance of Varroa destructor to Formic and Lactic Acid Treatment-A Systematic Review. Veterinary Sciences, 12(2), Article 144. https://doi.org/10.3390/vetsci12020144
Su, T.-S., Wu, C.-C., Lin, T.-Y., & Liu, C.-H. (2026). Beehive-entrance imaging and deep learning for real-time monitoring of Varroa destructor in apiculture. Journal of Invertebrate Pathology, 214, Article 108465. https://doi.org/10.1016/j.jip.2025.108465
