Propolis – Another 5 Percenter

Bee Culture, May 2009

by Walt Wright

Several years ago (July 06), the first article on “five percenters” appeared in this magazine. That submittal dealt with the gains of adequate hive ventilation. It was stated that other 5 % subjects existed, but this beekeeper has been preoccupied with more important subjects since that time – like CCD. Having had my say on nutrition as a factor in the CCD epidemic, we can return to general beekeeping considerations.

To recap the classification of five percenters, several worker jobs can be considered as occupying hive populations in activities that do not directly support honey production. The effects of a large portion of hive population engaged in non-production activities is difficult to measure, and is definitely not obvious to observation. But it should be easy to understand that bees engaged in work not related to your goal of honey production would make some dent in that production. Since the diversion of that portion of the work force is not readily measurable, we just arbitrarily assign that consideration to the 5 % classification. Some will be more or less of that much impact, but the combination of all of them could be worth the effort to minimize the effects.

The subject here is propolis – that stuff that glues everything together in a beehive. It gets a fair amount of bad press in the literature, and is reported to be collected from plant resins. I personally have never seen bees collecting those resins at their natural source, but I see the effects. I have occasionally seen them retrieving some propolis from boxes left in the hot sun long enough for the propolis to warm to its tacky state. They carry it on the spurs of the “pollen basket” – much like a pollen load. Once applied in the hive, it hardens into a brittle solid that often defies removal by a standard hive tool.

Just yesterday (2-17-09) I showed a local beekeeper how to checkerboard a colony for swarm prevention and increased production. He winters in a deep and a shallow – ten frames. Since it was my game, he watched and I worked. Who knows how long those shallow frames had been in the same position, but they were well propolized. To shorten a long story, it took four hours to do 8 colonies, but I was careful not to wreck any frames in the process. When we were done, I told him it is much simpler and quicker with nine frame brood box spacing. He muttered some negative comment and I left for home. I don’t think there is any danger that he will ever adopt my management approach.

Yes. Propolis is a problem for the keeper, but a valuable defensive asset for the bees. The intent of this submittal is to provide some recommendations for a compromise between you and your bees.

First, we need to understand the defensive nature of the use of propolis by the bees. Consider for a moment the size of larvae of the wax moth or small hive beetle. They are tiny at hatching. If that pest larvae hatchling can find a crack or crevice of a size that the bees can not penetrate, it is safe for the moment. Often, the adult pest actually deposits her eggs in a protected spot to start the process.

To roust the pest from the colony, whether adult or larvae, the bees use their mandibles. That means they need head room for access. Any space, from a crack up to bee access space is filled with propolis. Even an inside 90 degree angle, like the inside corners of the hive box, are rounded (construction jargon – coved) to insure access to the deepest part of the angle.

Both the wax worms and the beetle larvae have a defensive mechanism to protect them during development. The wax worm builds a webbing to keep the bees at bay. Webbing to protect the larval stage is not unique to the wax moth. Many other insects use that technique. You are probably familiar with the tent caterpillar that feeds at night on tree leaves and retreats to the tent during daytime when predatory birds are active. As the wax worm larvae grow, they extend the webbing to eventually completely enclose the whole brood nest where pollen is stored. The bees are helpless to stop the expansion of the larvae base of operations, so they take the preventive approach of stopping them before the larvae get started – by propolizing hiding places for eggs and small larvae.

The beetle larvae have a different defense mechanism against the bee colony invaded during development. When I saw a maturing beetle larvae climb up one cell wall partially filled with nectar, and nonchalantly crawl down into the adjacent cell of nectar, headfirst, it reminded me of the botfly larvae. For those of you unfamiliar with the botfly life cycle, the adult lays an egg on the skin of a warm blooded animal. The larva penetrates the skin and feeds on the flesh below (sometimes called wolves). As it grows, a pocket of fluid (lymph?) develops – making a bump on the skin surface. Often the first clue to the animal’s problem is a wet streak from the larva’s breathing hole. Existing in a liquid environment, it maintains a port in the outer skin to come up for air – much like the seal’s hole in overhead ice. The beetle larvae hatchling only needs to make it to an open cell of nectar/honey to be “home free.” (Safe in the kid’s game of hide and seek).

As much as I have read about the beetle, I have seen no reference to the larva defensive mechanism of living in a fluid environment. The clues are there. Honey on the honey house floor, larval feces in the honey, and slime on the bottom board are reported vividly. Pictures of larvae frolicking in the bottom board “slime” abound. Do the “experts” not recognize that living in a fluid is the larvae defense mechanism? Bees are not known for their swimming skills. Moving on, it should come to their attention, sooner or later, that the “slime” is caused by honey oozing from the breathing holes of the larvae.

If you paid any attention to my past opinions you will know that I am not enamored with Langstroth hive design. Propolis tends to make the objective of movable frames more difficult than it needs to be. With all the cracks and right angle turns in the frame rest area of the box rabbet, that area is often a solid mass of propolis. The frame spacing shoulders of a frame are cemented together for the full depth of the spacing width of the end bar. For either the frame rest area or the spacing shoulders of the frame, when you break the propolis joint, some hardened propolise stays on both pieces of the separated joint. Unless you put it back in the same position it came from, the chunks on both sides will not match up, and the frame will not go into a different slot willingly. Get a bigger hammer! An alternative is to scrape the outside perimeter of each frame down to the wood as removed, all the way around, and clean the frame rest rabbet with your trusty hive tool. Very labor intensive. The bees are certainly entitled to implement their time – honored method of pest control, and to their credit, they often err on the side of safety. Too much is better than too little.

Having wandered through more miscellaneous misinformation than you thought you wanted to know, will try to drift back to the subject of this submittal.

One advantage of the metal nine frame spacers that we use from the bottom board to the cover was not mentioned in the article (BC Jan 06) on nine frame brood chambers. The sides of the position slots are angled up and away from the bottom width. With some gentle leverage off the next adjacent frame the frame lifts up and away from the base of the slot. The primary resistance to upward movement is the propolis between spacing shoulders and excessive propolis at the upper end of the top bar. (More is better.) It’s easy and quick to remove the excess at the end of the top bar and slicing the propolis between spacing shoulders is not that tough. The eighth inch space will accommodate the thickness of the hive tool. This paragraph is only relevant to upcoming recommendations.

One of my favorite contributors to this magazine years ago was O.B. (Older But) Wiser – an obvious pen name. He was located somewhere in the desert southwest and called ‘em like he saw ‘em – without regard for other opinions. My kind of guy. However, he wrote one article I was inclined to disagree with. (We’re inching back to the subject of this submittal.) He recommended a late winter “clean up” of hive parts “down to the toenails.” His description of clean up included scraping all woodenware inside the hive to remove unnecessary wax and propolis, to start the new season with a neat hive. If he lived far enough south that the bees maintained brood all winter, they would emerge from winter with wax making capability. In that case it would be okay to remove wax stored as bridging and burr comb. Further north, the colony has uses for their stored wax in early season. Give them credit for limited waste of resources – they are efficiency experts.

(We’re back to the subject) Scraping all the propolis internal to the hive would cause the colony to start over on sealing cracks and crannies. If they get a vote, they will not abandon their pest management program.

The literature tells us that propolis workers are a dedicated group of specialists. They gather the goop in the field and putty the cracks. No intermediate bees in the process. I’ll take their word for that much. The bees are very good at apportioning the work force to accomplish multiple tasks in parallel. It stands to reason that the greater the need for propolis the more of the work force is applied to the task.

It’s the application of that portion of the work force that is the subject of this submittal. To qualify as a five-percenter, there be must ways for the beekeeper to minimize that work force to reduce the number of bees necessary to perform that duty. Presumably, any portion of the work force relieved of that duty will contribute to honey production. That colony has a finite amount of energy to apply to generating surplus honey is the basic premise of the five – percenter classification.

That opens the question of what can we do as beekeepers to reduce propolis needs. This season I will do two things to get started. Since the frame rest rabbet area is a known inconvenience area for me, that problem will be attacked on a priority basis. Frames have been modified to slope the sides and ends of the top bar tab (ear) that supports the frame weight on the box rabbet. It will not be necessary for the bees to fill the space at the end of the frame and should reduce the need for propolis on the base of the tab all way around the tab joint to the frame rest ledge. Propolizing the joint is expected, but there should be less of it. The slopes (45 degrees) open up the angle and should provide more head room without weakening the tab strength much. The figure shows the end tabs of three frames. The center frame is unchanged, while the left and right frames have been modified. The left frame tab is angled at the end only, and the right frame tab is angled on the end and both sides for comparison of effects.


Secondly, on a lower priority, any new boxes assembled this season will have a flat surface, top and bottom. It’s easy to assemble a box that does not have a flat surface and causes the bees to fill the cracks left between boxes where there are open spaces. If you look at a propolized box joint, when separated, you can often see evidence that the mating face was propolized from both inside and outside – none in the middle, because the bee pushes the propolis into the crack with its “feet”. Occasionally you will see a propolis worker filling a crack on the outside. I am puzzled by the outside work. “Bees are insects and don’t think.” It is difficult for me to believe that a bee trained to the entry/landing board accidentally stumbles on a crack that needs filling at the back of the hive – 4 stories up.

To insure flatness of the mating surfaces a test surface is needed. Steel plate would do it. A box on the flat surface will be trimmed until no light is seen between the plate and the box. High spots in mating surfaces can be trimmed in many ways. Small amounts can be done with a power sander with coarse grit, but that is fairly slow. For larger adjustments, I have been known to drag a circular saw backward along the edge to take off the desired amount. Not recommended for the novice circular saw operator. Point is: I have been making boxes with relatively flat surfaces for years, but intend to do a better job in the future.

Making the box mating surfaces absolutely flat will pay dividends for the life of the box. Each year, less workers are needed to propolize the box joints which should improve your honey yield by some unknown amount. A more positive gain is that in beekeeper time spent in routine hive management and honey house operations. When honey supers are cycled through the honey house each season, it’s nearly mandatory to scrape the box joints, top and bottom, down to the wood. Depending on how well the propolis is cured that can take time and effort, not needed on the tight fitting joint.

If not scraped clean for reuse more propolis accumulates each season because of last season’s mismatch of residual accumulation. If you only had a few hives, it might be feasible to put boxes back on in the same sequence they were used last season – forgoing the clean up and reducing propolis work. Otherwise, clean mating surfaces.

It’s a little late for this season, but there is another propolis reduction to be implemented. My boxes are ready to go for the build up starting next month. With nine frame spacers mounted on the frame rest, there is no need for the spacing shoulders on frames. The one eighth space is regularly propolized. By shaving a sixteenth off both sides, the space is increased to a quarter inch (head room) which would obviate the need for propolis. I look forward to getting all – up with these changes and returning to the “joys of beekeeping.”

Two other five-percenters on the list remain untreated. Paying attention to bee space between boxes and over-supering are both relevant to the closing comment. When supering “as needed”, significant interbar comb results. Over-supering results in very little comb being added between boxes.

Perhaps we’ll get around to those other five-percenters and maybe not. But in case you already take care in those areas, a flat mating surface on boxes will make it easier to separate boxes during hive breakdown or harvest. Be advised that my overall approach to hive management is oriented to maximizing honey production with the least time and effort on my part.

The referenced, older articles can be found on line at . Click on Point of View.

In summary, with the beetle spreading across the country, it would behoove us to pay more attention to the merits of propolis. I believe that we can help the bees and our production by taking steps in advance to minimize the need for small pest larvae defense.