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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 with your counting stories, please send an email to mindingyourbeesandcues@gmail.com
Minding Your Bees and Cues
Comb Considerations
By: Becky Masterman & Bridget Mendel
Comb Costs
Removable combs arm beekeepers with multiple management manipulation options. Raise your hand if you have found yourself in the middle of your apiary with multiple colonies open and moving frames from one colony to another to boost, requeen or feed. Most U.S. beekeepers house colonies in boxes with removable frames and we should be eternally grateful to Procopovych and Langstroth for providing us with systems to inspect, sample, harvest honey, manage pests and pathogens, transport, split and requeen with relative ease. This great power that we have as superorganism animal keepers comes with a cost. It is too easy for beekeepers to use comb past its replacement time and not rotating new frames into your colonies can impact their health and honey production.
Pesticides in Comb
Research teams have reported pesticide contaminated pollen and nectar loads in both urban and suburban apiaries (Démares et al., 2022) and commercial apiaries agricultural areas (Mullin et al., 2010). Contaminated food stored in cells can contaminate the beeswax comb. While negative impacts of pesticide exposure during the rearing of queens (Milone and Tarpy 2021), workers (Wu et al., 2011), and drones (Fisher et al., 2018) have been reported, research is needed to help beekeepers understand these risks and implement the best replacement methods for combs.
Cappings in this photo show the accumulation of propolis and cocoons in the wax, darkening it over time. Newer wax is on the right, with older, darker, older wax on the left. Photo credit: Rebecca Masterman
Pathogens in Comb
Moving frames from colony to colony, apiary to apiary or beekeeper to beekeeper is common practice, but depending on the pathogens present, it could be a tragic move for your bees. While we are all warned about detecting American Foulbrood (AFB) scale in combs, pathogens like viruses and bacterial and fungal spores are not identifiable by sight. Beekeepers must use clues, like scales, diseased brood and adults to determine the potential pathogen presence and thus risk in their combs. What are the best practices regarding pathogen identification and transfer? We looked north and found an excellent primer on biosecurity. While it isn’t a short read, it is unlikely time wasted to visit the Canadian Government’s Honey Bee Producer Guide to the National Bee Farm-level Biosecurity Standard. (https://inspection.canada.ca/en/animal-health/terrestrial-animals/biosecurity/standards-and-principles/honey-bee-producer-guide)
Cell Size
A research team based in Saudi Arabia interested in the negative impact of comb age on colony health reported on the reduction of cell size as combs age (Al-Kahtani and Taha, 2021). The accumulation of cocoon, pollen and propolis in comb over time result in a significantly smaller space for brood development and food storage. Their study examined cell sizes in comb up to six years old and reported a jaw dropping 43.33% decrease in newly emerged worker weight compared to new comb. Based on their measurements, their team recommended that beekeepers replace comb every three years. Why three years? There was a significant decline in honey production in colonies with four to six year old comb. One year old comb colonies had 23.98% more honey production compared to colonies with four to six year old combs (Taha and Al-Kahtani, 2019).
Replacement
Comb replacement is a financial and resource heavy investment, but when done consistently over time and during the right part of the season (nectar flow and with queenright colonies!), the financial burden can be spread out evenly and minimize operation impacts. A conservative comb replacement regime with strategies for implementation is recommended by the United Kingdom’s National Bee Unit. They suggest comb replacement every three years to protect colonies from pathogens and the accumulation of varroacides. Their straightforward approach to comb replacement and comb disposal is a valuable resource for beekeepers (https://www.nationalbeeunit.com/assets/PDFs/3_Resources_for_beekeepers/Fact_Sheets/Fact_21_Replacing_Old_Brood_Comb.pdf).
We understand that removing what looks to be perfectly acceptable brood combs from your operations might feel wrong, both financially for the beekeeper and energetically for the bees. We have a few suggestions to help make this culling process less painful:
- Time flies for beekeepers and not knowing when a frame was put into operation can make a 10 year old frame pass for a four year old frame. Some of the best beekeepers out there (like Ana Heck and Dan Wyns of Beehavior Ranch, LLC in Michigan) make sure their frame ages are clearly marked by stamping them with the year they are put into operation (see photo). If you aren’t ready to invest in a branding tool, start with a permanent marker.
- Mark frames with likely pesticide exposure (like those with pollen entombed with propolis) and move them out of your operation. This move doesn’t need to be immediate, but marking an X on a frame with your hive tool and making sure those frames are in the bottom box when preparing your colonies for winter, can make their removal the following spring easier when they are emptied of resources like brood and food.
- Mark frames with known disease presence and rotate out in the same way as the frames above. This X will also stop you from moving potentially pathogenic frames from colony to colony if the brood becomes asymptomatic later in the season.
- We like to deep super our colonies with frames of foundation during the nectar flow and rotate the new, wet comb into our operations after the honey has been extracted. The bees appear to appreciate it.
Convinced?
We find comb considerations to be complex. As beekeeping has changed over the decades (think fewer nectar producing plants, increased pesticide use and the arrival of a destructive pathogen vectoring mite), it is important to recognize our increased responsibility to the animals we keep. You wouldn’t think twice about the need to clean out a stall, pen, or cage. Honey bees make their nests appear to be self-cleaned, until disease and pesticides impact colony health and we can see that something is wrong. If the pesticide and pathogen comb contamination issues are not convincing comb replacement incentives, maybe the cell size and potential honey crop reduction are?
Keeping track of comb age can make sticking to a replacement plan easier to implement. Photo credit: Ana Heck, Beehavior Ranch LLC.
References
https://en.wikipedia.org/wiki/Petro_Prokopovych
https://en.wikipedia.org/wiki/L._L._Langstroth
Démares, FJ., Schmehl, D, Bloomquist, JR., Cabrera, AR., Huang, ZY., Lau, P., Rangel, J., Sullivan, J., Xie, X., & Ellis, JD. (2022). Honey Bee (Apis mellifera) Exposure to Pesticide Residues in Nectar and Pollen in Urban and Suburban Environments from Four Regions of the United States. Environmental Toxicology & Chemistry, 41(4), 991–1003. https://doi-org.ezp1.lib.umn.edu/10.1002/etc.5298
Mullin CA, Frazier M, Frazier JL, Ashcroft S, Simonds R, vanEngelsdorp D, Pettis JS. (2010). High Levels of Miticides and Agrochemicals in North American Apiaries: Implications for Honey Bee Health. PLoS ONE; 5(3): e9754. https://doi.org/10.1371/journal.pone.0009754 PMID: 20333298
Milone JP, Tarpy DR.(2021) Effects of developmental exposure to pesticides in wax and pollen on honey bee (Apis mellifera) queen reproductive phenotypes. Scientific Reports. 11(1):1-12. doi:10.1038/s41598-020-80446-3
Wu, JY, Anelli, CM, & Sheppard, WS. (2011) Sub-Lethal Effects of Pesticide Residues in Brood Comb on Worker Honey Bee (Apis mellifera) Development and Longevity https://doi.org/10.1371/journal.pone.0014720
Tomé, HVV, Schmehl, DR, Wedde, AE, Godoy, RSM, Ravaiano, SV, Guedes, RNC, Martins, GF, Ellis JD. (2020) Frequently encountered pesticides can cause multiple disorders in developing worker honey bees, Environmental Pollution, Volume 256,113420,ISSN 0269-7491, https://doi.org/10.1016/j.envpol.2019.113420
Fisher A, II, Rangel J (2018) Exposure to pesticides during development negatively affects honey bee (Apis mellifera) drone sperm viability. PLoS ONE 13(12): e0208630. https://doi.org/ 10.1371/journal.pone.0208630
Al-Kahtani SN, Taha E-KA. Effect of comb age on cell measurements and worker body size. PLoS ONE. 2021;16(12):1-10. https://doi.org/10.1371/journal.pone.0260865
El-Kazafy A. Taha, Saad N. AL-Kahtani (2020) The relationship between comb age and performance of honey bee (Apis mellifera) colonies, Saudi Journal of Biological Sciences, Volume 27, Issue 1, Pages 30-34, ISSN 1319-562X, https://doi.org/10.1016/j.sjbs.2019.04.005
