Replacing old comb can seem like a time-consuming task, but it will not only decrease the risk of disease and accumulated toxins but significantly increase the productivity of your hive!

Hives with combs replaced regularly (every 1-3 years) store significantly more pollen, produce far more honey and rear more worker brood.   

Honey bee colonies in the wild 

Honey bee colonies in the wild have a natural way of recycling old comb. 

On average a colony can survive for about 6 years in the wild (Seeley, 1978). Any wax or honey comb that is left behind is removed and “cleaned up” by wax moths, mice, beetles and other scavengers, leaving an empty cavity free of contaminated old comb for the next colony to live in. In managed hives it is the beekeeper’s responsibility to replace and recycle old comb. 

How dark is too dark, and why does it matter?

Why do frames turn dark?

Each time a larva pupates, it spins a silken cocoon that remains in the cell after the adult emerges. Over time as more bees hatch from the same brood cells, silk accumulates against the cell wall. Eventually, the brood frames turn darker and darker and the diameter of the cell shrinks. Smaller and smaller bees hatch from these over-used cells. 

Consequences

• Larvae may be forced to moult pre-maturely i.e. nurse bees cap the cells before larvae have developed to its largest size potential (Abdellatif, 1965).
• Adult bees with lower body weights have reduced lifespans (Black, 2006).
• Smaller bees have a reduced capacity to carry pollen and honey (Mostajeran et al., 2006).
• Drones of smaller size are outcompeted by larger drones. Drone body size is correlated with sperm production. Larger drones produce more sperm (Rangel & Fisher, 2019). 
• Old combs have less space for honey to be stored
• Workers raised from colonies with old comb raise smaller queens 

Figure 1 shows frames from a brood nest that have turned dark over time (~3 years) and are ready for replacement. Some frames may need to be replaced even earlier than 3 years by the time they are as dark as in the photograph shown (Figure1). Most importantly, it is time to replace frames before a significant impact on colony productivity is experienced.

Impact on colony productivity

Let’s compare hive productivity of colonies with new (1-3 years) versus old (4-6 years) comb (Taha et al., 2021).

Colonies with new comb:

• store up to 67% more pollen 
• store almost 90% more honey 
• rear about 97% more worker brood 

This vast difference in productivity is explained by larger bees being able to gather more resources, raise larger amounts of well-fed brood and therefore build and maintain larger colonies. 

Weak colonies consume a large part of the collected nectar while trying to build up their populations, making for a smaller or non-existent honey crop. In small colonies, a larger proportion of the total population engages in brood rearing than in stronger colonies where a larger proportion of field bees is available to gather nectar.

Wax comb- toxins and pathogens

Wax comb consists primarily of hydrocarbons and ester components, which act like a sponge. For this reason, wax can absorb pesticides and heavy metals, but also accumulate fungal and bacterial spores, all of which can be detrimental to the colony’s welfare and a risk to spreading disease in an apiary!

Would you think twice about replacing old comb?

What to do with old brood comb

Often not much wax can be retained from melting down dark, old brood frames. Any wax obtained is also dark in colour.  The best option is to burn old brood frames and bury the ash to comply with pest and disease management regulations (Biosecurity Code of Practice).

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Acknowledgements:

• Abdellatif, M. A. (1965) Comb cell size and its effect on the body weight of the worker bee, Apis mellifera L. American Bee Journal 105: 86-87.
• Berry, J. A., & Delaplane, K. S. (2001). Effects of comb age on honey bee colony growth and brood survivorship. Journal of Apicultural Research, 40(1), 3–8.
• Black, J. (2006). Honeybee nutrition-review of research and practices. In RIRDC (Issue 06). Publication No. 06/052. 
• Buchner, R. (1955). Effect on the size of workers of restricted space and nutrition during larval development. Wilhelm Roux Archive für Entwicklungsmechanik der Organismen 146: 544–579.
• Rangel, J., & Fisher, A. (2019). Factors affecting the reproductive health of honey bee (Apis mellifera) drones—a review. Apidologie, 50(6), 759–778. 
• Seeley, T. D., (1978) Life history strategy of the honey bees, Apis mellifera. Oecologia 32: 109–118.
• Taha, E. A., Rakha, O. M., Elnabawy, E. M., Hassan, M. M., & Shawer, D. M. B. (2021). Comb age significantly influences the productivity of the honeybee (Apis mellifera) colony. Journal of King Saud University – Science, 33(4), 101436.
• This article was peer-reviewed by Michael Holmes and Emily Noordyke.