Heat, as a form of energy, is critical for beekeepers to understand and bees to conserve.

Without a clear understanding of how heat is used in a hive, beekeepers will miss opportunities to aid in the flourishing of their bees — which is, of course, the chief responsibility of the beekeeper.

Bees instinctively know how to apply and conserve heat, but they are limited by their surroundings.

In this article, we’ll first outline a number of ways in which heat affects the survival of a bee colony. Later, we’ll describe the benefits of thinner walls between cells as it relates to thermal efficiency in a hive.

By developing a thorough understanding of heat’s role in a hive, the beekeeper will discover new ways of conserving it and consequently protect the creatures they so love.

Biology 101: A Quick Recap

Elementary biology tells us that a species’ primary objective is survival. Survival indicates that an organism — whether a single-celled bacterium or a 600-pound grizzly bear — remains living, which requires energy to do.

It’s simple enough to think of survival, then, as a trade between kinetic energy (i.e., energy in motion) and potential energy (stored energy).

Bees forage for nectar as humans search for the nearest burger joint.

It’s difficult for humans to naturally grasp the concept of trading kinetic energy for potential energy in the form of food. After all, we don’t find ourselves physically spent after a trip to the grocery store (or, rather, we shouldn’t!)

Think of the cheetah: She exhausts an enormous amount of energy (in a rather short amount of time) during her hunt of a gazelle. Eventually the cheetah must decide, “Do I continue burning precious energy for the chance that I may receive an abundance of potential energy, or do I throw in the towel now?”

Bees don’t chase after gazelles, but they do forage for nectar and pollen. 

As nectar is their primary source of energy in the form of carbohydrates, foraging workers must consider the return of their labor — i.e., how much food is provided to the hive for how much work it cost.

As it turns out, we are able to quantify the amount of energy harvested. 

How Heat Is Involved (And How It’s Helpful)

Now, the nectar collected by bees is only the raw ingredient for the actual entrée — honey.

Turning nectar into honey requires energy as water is removed via evaporation. Bees catalyze this process by absorbing some water themselves, warming the air with their body heat, and fanning the air with their wings.

A quick breakdown of the numbers for our honey recipe:

• Nectar is composed of 20% sugar and 80% water

• Honey is composed of 80% sugar and 20% water

• 1 pound of honey, then, requires 4 pounds of nectar 

  • 1 lb honey = 0.8 lbs sugar

  • 0.8 lbs sugar / [20% sugar] = 4 lbs nectar

But the numbers don’t end there. The process of converting nectar into honey requires additional energy in the equivalent amount of 2 lbs of nectar (on paper).

We indicate “on paper” because this equation assumes 100% thermal efficiency — i.e., that no heat energy is lost in the process. In actuality, a substantial amount of heat is lost as it flows from warmer areas to colder.

For a close-to-home example, think of how much harder the heater in your house works during the colder months (please excuse the pun).

This article by Derek Mitchell, which dives further into the numbers of thermal efficiency, reasons that 50% thermal efficiency is fair and accurate. 

If the bees lose half of this heat due to thermal inefficiency, we’ll have to double the amount of original nectar required to convert nectar to honey (2 lbs). 

Now we’ve arrived at a total of 8 lbs of nectar to produce 1 lb of honey. 

Sit back and awe in wonder at this amazing feat for a moment.

You can now see why thermal efficiency is incredibly important to the survival of the honeybee.

As a final note on the importance of heat in the hive, consider this article we published in July of 2020 on the role of heat in treating varroa infestation. It’s been shown that heat inhibits varroa infestation, and these thermal treatments are only increasing in popularity as more real-world success stories surface.

In sum, heat has been demonstrated to be a valuable “resource” in the hive during honey production, colder temperatures, and for varroa treatment.

How Much Heat Is Too Much?

Conventional wisdom says that heat is generally bad for bees.

This is true, but the question is to what extent. Alison McAfee explains in “Thermal Treatments for Varroa” that some laboratory tests have shown heat to be just as detrimental to drones as mites, but the real-world examples suggest otherwise.

Bees are adaptable creatures, perhaps more so than mites. By tolerating increased temperatures for a time, the overall health of the colony might stand to increase.

But the temperatures suggested here are really beside the point of this article. Slight temperature increases with the goal of increasing thermal efficiency is unlikely to have a serious effect on a colony, as we’ll see more below.

The risk lies more with ineffectiveness than with harm.

Thinner Cell Walls Can Increase Thermal Efficiency

We have seen how increasing thermal efficiency stands to reduce the workload of bees required in honey production. 

When less nectar is required in the honey recipe, less time is spent foraging in the environment, enduring its elements, and collecting potentially harmful chemicals. Likewise, less nectar translates to less wingbeats during the evaporation process, saving both energy and potential damage to their wings.

But how might a beekeeper apply this knowledge? How might they increase a hive’s thermal efficiency? 

One answer may involve assisting heat transfer between cells. By incorporating a foundation with thinner cell walls, bees will draw comb with thinner walls (and waste less energy in the wax-making process). Thinner walls mean more heat is transferred between cells, slightly raising the temperature of its interior and contents.

When a cell contains an egg, larva, or pupa, this has a mostly neutral effect.

But when a cell contains a nymphal Varroa mite or the makings of honey, this is entirely a good thing.

Conclusion

Thermal efficiency is highly important to the health and productivity of a colony. 

We’ve seen how conserving heat reduces the stress on bees to make honey, as well as some ancillary benefits of a warmer cellular temperature.

At Premier Bee Products, we’ve been vocal about the advantages beekeepers have enjoyed by incorporating Premier Foundation in their hives. One of those benefits comes from its 36% thinner cell walls, which, as this article alludes to, is a major draw for both bees and their keepers.

Perhaps bees consciously choose Premier Foundation over others due to these more favorable cell dimensions (more likely it’s due to better smelling wax coatings, but that’s another topic for another day). 

Whether intentional or not, however, we wholeheartedly believe every bee stands to live a less stressful life through the aid of Premier Foundation.

Sources

Mitchell, D. (May 22, 2019) “Thermal Efficiency.” Bee Culture. https://www.beeculture.com/thermal-efficiency/

McAfee, A. (January 1, 2020) “Thermal Treatments for Varroa.” American Bee Journal. https://americanbeejournal.com/thermal-treatments-for-varroa/

“Why and How Bees Forage.” PerfectBee. https://www.perfectbee.com/learn-about-bees/the-life-of-bees/why-and-how-bees-forage