Final report for FNE24-094
Project Information
Our project was designed to investigate the viability of overwintering honeybee queens in the Northeast in an indoor environment. We utilized an indoor honeybee storage unit manufactured by HiveTech to perform our trial.
We built three queen banks based on instructions from our technical advisor (Ellen Topitzhofer) who has performed extensive queen banking trials. Storage unit temperature and humidity conditions were informed and selected based on past research trials conducted by beekeepers in collaboration with HiveTech (see details below). Each bank was treated with Amitraz before it was made queenless in September 2024, and treated again with oxalic acid dribble in November 2024.
Queen banks in our trial appeared to exhibit and succumb to severe dysentery conditions. Temperature and relative humidity levels were set based on prior research. However, we hypothesize that ambient temperature that a queen bank requires for winter survival is likely higher than what a normal hive (containing a single queen) requires. This higher temperature selection led to greater mobility as well as food intake by queen attendants. Increased attendant mobility and food intake led to a higher demand for defecation than hives that overwinter (cluster) at a lower temperature. Lack of consistent fresh air intake in our storage unit may have also negatively impacted the bees' ability to effectively cycle fresh air through their hives. We suspect these variables, combined with the lack of outdoor access (for the purpose of defecation), created the conditions for dysentery outbreaks in our queen banks.
On the contrary, our outdoor hive winter survival rate was 82%, indicating that our winter preparation is currently effective in preparing our honeybees for successful overwintering survival in the Northeast. Leading up to winter, outdoor hives receive a 2" rigid foam top board insulation, as well as oxalic vapor mite treatments if necessary based on Summer & Fall mite-wash data. Of the 82% surviving colonies, most colonies went on to build up rapidly in Spring for honey and queen production, and only 12% needed to be requeened.
More research is needed to determine the viability of overwintering multiple queens within a hive (queen bank), and more research is needed to determine efficacy of indoor overwintering in the Northeast region. Based on our trial's lack of queen survival (0%), we would not recommend or pursue this approach at this time. Future research trials should consider adjusting infrastructure set-up as well as temperature and humidity variables.
This study will evaluate the efficacy of overwintering honey bee queens indoors in climate controlled storage when comparing queen banks to nucleus
hives. Utilizing recommended temperature, humidity and queen banking techniques, we will overwinter 100 queens in queen banks and 40 nucleus
colonies in a climate controlled modular storage facility.
Our objectives:
- Assess the percent survival of queens banked overwinter in bulk indoors for 4 months.
- Compare survival of 5 indoor queen banks with 20 queens per bank to queen survival of 40 nucleus colonies with a laying queen.
- Analyze the sperm viability and morphology of queens overwintered in bulk in an indoor climate controlled environment utilizing laboratory
testing. - Evaluate the performance of queens overwintered in queen banks and nucleus colonies in a climate controlled environment by comparing open & capped brood, population density, and brood disease prevalence when introduced to hives.
- Utilize a cost benefit analysis to evaluate the economic viability of indoor temperature controlled storage of honey bee queens when comparing queen banks to nucleus colonies.
- Disseminate results to 500 beekeepers in the Northeast with the goal of assessing how climate controlled technology could supply the market with localized honey bee genetic stock, making Northeast beekeeping more sustainable.
“Bee Informed Partnership” (BIP) data shows that winter loss rates in 2022-2023 were at 37.4%. This is an increase of 13.2 percentage points from the winter loss rate of 24.2% from the year prior. This is more than a 50% increase in winter hive loss over a single year. According to the UN’s Food and Agriculture Organization 90% of the world’s food supply comes from about 100 crop species, and 71 of those crops rely on bees for pollination. Honey bees play a vital role within our food system and their population decline has direct negative effects on our food security.
Winter in the Northeast region poses a myriad of challenges for honey bees; including more pronounced temperature and humidity changes and increasing pest pressure. Pest pressure includes the presence of varroa mites as well as viruses such as honey bee paralysis viruses, deformed wing virus and nosema. Desai, S. found that “Varroa mites weaken the bee’s immune systems, making them more susceptible to viruses, and act as effective vectors to spread viruses within colonies [58, 61–63]. Varroa and DWV together affect storage lipoproteins (vitellogenin) necessary for winter survival [16] and affect immune system function [64–66].”
Climate is a crucial factor in the successful overwintering of honey bees. Humidity in hives must be kept low, while temperature must be maintained at 94°F. In winter, the core temperature of the hive must not fall below 55°F. The combination of cold and wet winter weather depletes food sources and can have a negative impact on hive health.
Due to these challenges, innovations are necessary to improve sustainability and profitability of beekeeping in our region. Climate controlled storage of honey bees is a known and established practice in Canada where it has demonstrated success improving the health and profitability of beekeeping. Climate controlled storage of honey bees in the Northeast could provide an innovative opportunity for beekeepers to reduce colony losses, increase the number of locally adapted early season queens available in the region, and minimize dependency on Southern-sourced queens & packages. Queens can be “banked” in climate controlled storage using full sized hives called “queen banks” designed to store multiple queens in one hive unit over winter, or queens can be individually placed in small hives called “nucleus colonies.” However, with high winter losses, climate controlled storage units could prove to be more efficient and cost effective at overwintering a higher number of queens.
Overwintered queens offer beekeepers a smooth start to the spring growth season. Rather than purchasing queen bees from another region to introduce into the Northeast, the queen bees are already present from the year prior and have demonstrated winter-hardy qualities and characteristics. This gives the hive coming out of winter a natural progression into early spring brood-rearing season. Overwintered queens support the sustainability of Northeast beekeeping by reducing the reliance on shipped queens from outside of the region, and increasing the development of localized honey bee genetic stock. Our project proposes that utilizing a climate-controlled overwintering environment for bulk honey bee queens will help to increase the overwintering survival rate for honey bees in the Northeast region. As it has been demonstrated thus far in the proposal, we know that the overwinter survival of queen bees could help:
- Reduce the amount of queen bees being shipped in from outside of the region in early spring and therefore maintain healthier queens with more robust spermatheca.
- As demonstrated in research by CRSAD in Ontario, Canada, shipped queens can undergo spermatheca damage depending on shipment temperatures. Spermatheca damage occurred in nearly ⅓ (32%) of shipped queens.
- Increase localized survivor queen stock.
- Reduce southern migration necessary for honey bees to achieve overwintering success.
- Reduce the effects of pests and viral load on honey bees, since transport leads to highly stressful conditions for honey bees. Stress leads to weakened immunity and higher pest and viral load.
In summary, the results from this grant will help us to improve the survivability of honey bees in the Northeast region, and increase the production, dissemination and exchange of northern queen genetics – ultimately strengthening the sustainability of beekeeping in the Northeast.
They Keep Bees (TKB) operates multiple production and research apiaries across Western Massachusetts for queen grafting, mating management, mite monitoring, and longitudinal data collection. TKB’s 300-colony operation ensures sufficient sample sizes for statistically meaningful comparison across assay types. The farm is capable of rigorous research, grounded in our consistent colony monitoring and standardized recordkeeping throughout the season.
The team maintains an extensive network of beekeepers in MA, VT, NY, and RI.
Cooperators
- - Technical Advisor
- - Technical Advisor
- - Technical Advisor
Research
Hives that eventually became queen banks were assembled in the Spring of 2024. These hives were maintained with a single brood break in June, as well as one oxalic acid treatment in late July and an oxalic dribble in November 2024 (after assembly). Feeding occurred after the autumn knotweed nectar flow concluded in mid-September. Feed consisted of 2:1 sugar syrup provided in frame feeders within each bank. Feeding continued until the end of September, which gave the banks ample time to dehydrate and cure feed prior to entry into the HiveTech unit.
Following the Guide to Honey Bee Queen Banking and guidance from our Technical Assistant Ellen Topitzhofer at Oregon State University we began to prepare queen banks for winter in September 2024. On September 5th, 2024, we pulled the original queen from four double-deep hives located in the field apiary. We introduced 10 queens into each bank, except for one which contained 13 queens (this hive had an observably larger cluster at the time of bank creation). We started with 43 queens across four banks as instructed by our technical advisor, Ellen Topitzhofer. Queens were held on JZBZs style shipping bars in JZBZs style plastic shipping cages, pressed into a typical Langstroth frame and attended to by nurse bees within the hive.
The queen frame was located in the center of the top box, allowing for greatest access to the centralized typical cluster of bees. After the banks had been broodless for three weeks, we treated all banks with Amitraz, locating the strip in the bottom box to keep sufficient distance from the queens. Due to the warm weather conditions, we delayed bringing queen banks into the HiveTech unit until temperatures dropped. Significant temperature drop did not occur until late November. As a result, these banks stayed in the field without an actively laying queen from September until late November. We performed routine checks on the banks to observe queen health over time. The following is queen loss data that occurred between September and late November:
10/1/24: 4 lost, total remaining: 39
10/7/24: 5 lost, total remaining: 34
11/9/24: 2 lost, total remaining: 32
11/19/24: 3 lost, total remaining: 29
On 11/29/24, we condensed the banks into three banks and moved the banks into the HiveTech unit, with the intention that increased uniformity of conditions might stabilize queen survival. Temperatures within the HiveTech unit ranged from between 46F to 52F, with the thermostat set at 49F. Relative humidity ranged from 45% to 79%. The queen banks had screened bottom boards as well as unencumbered entrances for increased ventilation. Banks were placed on top of plastic pallets that also contained holes for effective ventilation.
We re-checked banks for survival on 12/15/24 and found loss of 10 queens across all three banks. 19 queens remained amongst three banks.
Observationally, we noticed a significant amount of attendant bee die off present inside of the HiveTech unit. This manifested as a very high number of bees dead on the floor around the hives. We would estimate between to six to eight-hundred bees were dead on the floor inside of the unit.
We re-checked banks for survival on 12/29/24 and found a complete loss of the remaining 19 queens across all three banks. 0 queens remained amongst three banks. There was a continued substantial amount of nurse bee die off we observed by dead nurse bees present on the floor of the unit.
All 40 nucleus colonies involved in the trial remained alive outdoors.
This project measured the survival of honeybee queens banked in double-deep Langstroth boxes from the beginning of September until the end of December. Originally, we intended to move the banks into the HiveTech unit earlier than late November, but seasonally above-average temperature and humidity conditions did not make this possible. The HiveTech unit was often reading above 90% humidity (with no hives present) during the month of November, due to rainy conditions.
Observationally, we hypothesized that some of the queen loss that occurred was the result of night-time chilling, or the cluster not effectively tending to the entirety of the banked queens. In nearly 100% of the loss instances, queens on the ends of the bar were the typical loss locations. We hypothesize that clusters were not able to sustain the amount of provided queens and chilling occurred, or clusters chose to reject the amount of provided queens for reasons unknown to us.
We also observed high rates of nurse bee die-off when banks were moved into the HiveTech unit. Observationally, we estimated between six to eight-hundred bees perished on the floor over the course of the month within the unit. We also observed evidence of early signs of nosema/dysentery exhibited by the bees present within the banks. This presented as dysentery at the entrances of the queen banks, on the walls of the HiveTech unit, on our suits as we inspected, as well as a large number of dead nurse bees outside of the bank hive entrances.
Our project was designed to investigate the viability of overwintering honeybee queens in the Northeast in an indoor environment. We utilized an indoor honeybee storage unit manufactured by HiveTech to perform our trial. Hives (queen banks) were prepared based on instruction by our technical advisor (Ellen Topitzhofer) who has performed extensive queen banking trials. Storage unit temperature and humidity conditions were informed and selected based on past research trials.
More research is needed to determine efficacy of indoor overwintering in the northeast region. Based on our trial's lack of queen survival (0%), we would not recommend or pursue this approach at this time. Future research trials should consider adjusting infrastructure set-up as well as temperature and humidity variables.
Queen banks in our trial appeared to exhibit and succumb to severe dysentery conditions. Temperature and relative humidity levels were set based on prior research. However, we hypothesize that ambient temperature that a queen bank requires for winter survival is likely higher than what a normal hive (containing a single queen) requires. This higher temperature selection led to greater mobility as well as food intake by queen attendants. Increased attendant mobility and food intake led to a higher demand for defecation than hives that overwinter (cluster) at a lower temperature. Lack of consistent fresh air intake in our storage unit may have also negatively impacted the bees' ability to effectively cycle fresh air through their hives. We suspect these variables, combined with the lack of outdoor access (for the purpose of defecation), created the conditions for dysentery outbreaks in our queen banks.
On the contrary, our outdoor hive winter survival rate was 82%, indicating that our winter preparation is currently effective in preparing our honeybees for successful overwintering survival in the Northeast. Leading up to winter, outdoor hives receive a 2" rigid foam top board insulation, as well as oxalic vapor mite treatments if necessary based on mite-wash data. Of the 82% surviving colonies, most colonies went on to build up rapidly in Spring for honey and queen production, and only 12% needed to be requeened.
More research is needed to determine the viability of overwintering multiple queens within a hive (queen bank) in the Northeast region.
Education & outreach activities and participation summary
Participation summary:
Though our indoor overwintering trial was not successful, we were able to refine how we Winter bees outdoors. From Fall 2024 to Spring 2025, a time of high hive losses across the country, They Keep Bees maintained an outdoor overwintering survival rate of 82%. Of the 82% surviving colonies, most colonies went on to build up rapidly in Spring for honey and queen production, and only 12% needed to be requeened. These successful overwintering rates outdoors make us confident that teaching about mite monitoring & management in Summer and Fall, wrapping and insulating hives in early Winter and applying oxalic acid treatment in late Fall all lead to successful overwinter outcomes.
In order to teach what we know works we conducted the following workshops about overwinter management in 2024 and 2025:
From May to October 2024 They Keep Bees (MA), in collaboration with Island Bee Project (NY) and Woven Roots Farm (MA) taught a cohort of 12 beginning and intermediate Northeast beekeepers how to set up, manage, treat and winterize honey bee colonies. Beekeepers received access to hands-on workshops, on farm demonstrations, webinars and a Signal thread for Q&A throughout the season. Beekeepers also received materials including hive equipment and overwintering wraps.
In 2024, as a part of this cohort, our team taught an outdoor overwintering workshop to 12 students, including a demonstration on oxalic dribble preparation and application and the installation of hive wraps for overwintering. Cohort members practiced installing hive wraps and insulation on hives in the Woven Roots Farm teaching apiary. Cohort members took home two hive wraps. Though we didn't have results from our study implemented in 2024, we taught methods for wrapping and insulating hives that we implement in our outdoor set up. We also taught the importance of low mite counts going into the winter- including how to assess mite loads in Summer and Fall, and determine treatment thresholds. Students performed winter wrap installation and implementation of oxalic acid dribble treatment for late Fall application. Twelve students received one-on-one support with preparing their own hives for winter from our leadership team via Signal, FaceTime and Zoom.
Through Winter of 2024-2025 we taught students the importance of hive autopsies to determine the probable causes of over winter losses. In 2025 the beekeeping cohort expanded to 18 participants in the Northeast. Beekeepers received access to hands-on workshops, on farm demonstrations, webinars and a Signal thread for Q&A throughout the season.
In Summer & Fall 2025 18 students were invited to two on-farm demonstration days. The first, in July 2025, we discussed the importance of preparing hives for winter by assessing queen health, combining hives as necessary and preparing hives for a Fall nectar flow. Together we practiced preparing oxalic acid and formic acid treatments to maintain low mite loads in Fall, a critical component of overwinter hive health in the Northeast.
In September 2025, students again gathered to do hands-on learning. In this workshop students assessed and recorded hive density in September, conducted mite washes and assessed nectar density during the Fall flow. Together we compared hives and ranked their preparedness for winter based on hive density, nectar and honey frames and mite loads to determine which hives were well prepared and which would need more support.
In November 2025 beekeepers from Island Bee Project (NY) and They Keep Bees (MA) led an Overwintering Webinar (password: p00Np&9i) on best practices in outdoor over wintering, and conducted a Q&A for cohort members, sent the recording to all cohort members who would not attend, and offered one-on-one follow up support via Signal and FaceTime.
The team is currently working on a "Wheel of the Year for Northeast Beekeeping". The Calendar will include outlinks to recorded webinars, instructional videos and other resources that demonstrate best practices in successfully overwintering colonies outdoors. This will be published in Spring 2026.
Learning Outcomes
Farmers who took our workshops and webinars learned strategies we've drawn upon for successful outdoor overwintering in the Northeast, which included:
- The importance of queen selection and genetics in Northeastern beekeeping.
- How to monitor for mites in the Summer with accuracy and consistency
- How to manage mites in the summer using both oxalic acid and formic acid when applicable.
- Mite treatment mixing and application for late Fall using oxalic dribble
- Maintaining strong hive density and assessing queen health from July-October.
- Use a solid bottom board and wrap hives in insulation where conditions are windy.
- Insulate hives with 2" foam board over a winter feeding rim.
- Employ emergency feed using sugar bricks.
- The importance of moisture control and a moisture control plan built on your location's winter conditions & humidity.
Project Outcomes
Research thus far has indicated significant challenges attaining indoor queen survival within this region. More research is needed to understand the variables negatively impacting queen survival.
Though our indoor overwintering trial was not successful, we were able to refine how we Winter bees outdoors. From Fall 2024 to Spring 2025, a time of high hive losses across the country, They Keep Bees maintained an outdoor overwintering survival rate of 82%. Of that 82% surviving colonies, most colonies went on to build up rapidly in Spring for honey and queen production. These successful overwintering rates outdoors make us confident that mite monitoring & management in Summer and Fall, hive density and queen health, wrapping and insulating hives in early Winter and timely application of oxalic acid treatments during the season, all lead to successful overwinter outcomes outdoors in our region.
In hindsight, there were multiple variables that we suspect negatively impacted our queen bank survival rates. We suspect the environmental needs of overwintering queen banks does not precisely align with the environmental needs of overwintering standard hives.
Judging by our observation of the trial queen banks both indoors and outdoors, we hypothesize that banked queens require a higher temperature to survive compared to single-queen headed hives. Before moving banks inside, we observed queen die off on the ends of the bars within the banks, indicating that those queens did not receive proper night-time thermoregulation support from the cluster of bank honeybee attendants. While this issue subsided upon moving the banks inside the temperature-controlled unit, other problems became prevalent indoors.
Indoors, we suspect that the higher temperatures that queens require to survive created digestive tract issues for bank attendant bees. For context, during winter, hives normally have a single queen per colony. This queen is tended to throughout the cold winter months through the process of attendant clustering. In our banking trial, a single cluster was responsible for thermoregulating, feeding, and tending numerous queens in each bank as well as maintaining their own energy (increased food intake as a result of increased energy expended to keep queens fed and tended), and digestive needs. We suspect the attendant's digestive processing needs were not sufficiently met, since they had a greater need to defecate due to higher relative temperature, higher energy output, and higher food intake. This, as well as a lack of outdoor access, led to defecation within the storage unit, as well as within and on the queen banks. We hypothesize that this led to a dysentery outbreak which contributed to a large die-off event.
Our recommendations for future trials would include the following:
- Smaller (in volume) bank boxes to assist attendant clusters in thermoregulating queens.
- Bank exit outlets to outdoors, allowing attendants to access outdoor environment to perform cleansing flights.
- Lower ambient temperature to encourage clustering, while also ensuring cluster can still tend to all queens present.
- Strong fresh air intake within indoor unit to encourage air cycling through banks.
While we will not continue implementing an indoor overwintering approach in our operation, we hope that research trials will continue to make progress in determining the viability of banking queens overwinter in the Northeast region.
We believe that cold-climate queen producers would greatly benefit from the findings of this trial.