Does one Size (of Comb) Fit All?
There has been a recent study discussing the effect of wax foundation size on the health of a honeybee hive and its individuals. It is fairly standard for beekeepers to have some kind foundation in their frames that may range in size from small (4.90 mm) to a more standard size (5.40-5.50 mm), meanwhile comb made without a foundation may range in size from 4.17-6.86 mm. Part of the push for smaller foundation size is due to other studies that have shown some decrease in varroa burden for hives that have smaller comb for brood rearing, additionally it seems to be linked to more hygienic behavior . In “Effects of Comb Cell Width on the Activity of the Proteolytic Systems in the Hemolymph of Apis mellifera Workers” the investigation into the impacts of the size of wax foundations on general hive health was continued.
As might be easily imagined, bees who developed in smaller cells were shown to be smaller in size throughout their entire bodies, and it was found that these smaller bees also tended to live longer and be more prone to becoming foragers as opposed to having jobs inside or nearer the hive (in relation to their age) than those raised in a standard sized cell. While these differences in development and behavior may not be clearly seen in a hive that has uniform comb foundations, in a natural hive there are much greater discrepancies in cell size which would then likely result in a wider difference between the behaviors, jobs, and size of the bees in an unmanaged hive. This study also noted that in conditions where small cell brood were raised by nurse bees from standard sized comb, there were higher value morphometric traits than those raised in a hive with nurse bees which are also from small cells. This potentially indicates that having a variety of cell sizes for brood does serve an evolutionarily advantageous purpose. These advantages are likely lost in settings wherein a beekeeper only uses small cell or standardized cell sized foundations in a hive.
Aside from the anatomical appearance or social behavior of bees raised on these frames, the activity of proteases was also analyzed. In honeybees, proteases are part of many processes such as development, immune response (which is similar to the humoral immunity in mammals), and digestion. Thus, an analysis of the protease activity in honeybees would be a way to reasonably estimate the potential state of the hive’s immune system. In order to test the protease and protease inhibitor levels of both the small cell and standard cell bees, a similar number of bees from each group at a variety of ages (1, 7, 14, and 21 days old) had samples of hemolymph taken to be analyzed for protein levels. Additionally, the activity of several pH dependent proteases, and the levels of protease inhibitors were also analyzed. These analyses showed that there were higher protein levels in the small cell 1-day old bees than that of the standard cell bees. However, the proteases and inhibitors were more active in the standard cell 1-day old bees. In the older age groups, the inverse was the case. Small cell worker bees showed higher levels of protease and protease inhibitors while standard cell workers showed a higher level of protein in their hemolymph.
It is also suggested that some of the differentiation in protein levels from the levels of protease and protease inhibitors in the small cell vs the standard cell worker bees could further confirm the idea that there may be a difference in worker behavior based on the cells they were raised in. There are generally higher levels of protein in the hemolymph of nurse bees (as is seen in the standard cell bees), and there are higher levels of protease and protease inhibitors in forager hemolymph. If this is the case, then there is not only a behavioral difference between small and standard cell reared bees, but also a physiological trigger to this. These findings may suggest that beekeepers could benefit by using multiple sizes of comb foundation in order to allow the differentiation of physiology and size that would be naturally occurring in a wild hive. This differentiation would potentially allow for a stronger hive that has at somewhat greater built in safety measures against disease or other threats to the hives wellbeing, as well as encouraging a specialization of the bees in the hive which would not be seen if only one size of comb were used. The use of various foundation cell sizes would allow a beekeeper to continue to discourage their bees from building large brood cells that may harbor more varroa while still encouraging natural diversity in their hives.
Dziechciarz, Piotr et al. “Effect of Comb Cell Width on the Activity of the Proteolytic System in the
Hemolymph of Apis mellifera Workers.” Animals : an open access journal from MDPI vol.
12,8 978. 10 Apr. 2022, doi:10.3390/ani12080978
Larsen, Alejandra et al. “Fundaments of the honey bee ( Apis mellifera ) immune system . Review.”