Thursday, June 29, 2017


I'm a big proponent of learning through reading and listening to experts. On the other hand, I also believe that you have to trust what you see with your own eyes. To quote Syrio Forel, the fencing teacher from The Game of Thrones, "My words lied. My eyes and my arm shouted out the truth, but you were not seeing."

That's why my #1 lesson learned from 2016 was pull old comb. Be ruthless. Forget what you've heard about reusing for three years and stop worry about the energy spent on drawing wax. After watching my bees for a couple of years, I could see the ones who'd been given a "jumpstart" with old comb constantly struggling. (BTW, by "old comb" I mean comb that was built during the previous season and contained brood at some point.) The ones that drew fresh comb outperformed "the cheaters" every time.

Finally, I came to the conclusion that I didn't need to keep old comb around because even during a horrible flow, my bees could still fill up their hives and start swarming. It made more sense to let them build fresh, clean comb. By doing so, I could kill two birds with one stone. 1) The bees would have a more healthful environment. 2) Swarming could be delayed (hopefully), or at least better managed.

Well, that was my personal conclusion, but now I've been vindicated! I read an article by Jennifer Berry and Keith Delaplane on the effects of comb age on honey bee colony growth and brood survivorship. Their research, conducted at the University of Georgia, compared colony growth and brood survivorship in hives with old comb vs. hives with new comb over a three-year period. It's a fascinating article, so I highly recommend reading it. However, if you decide not to, here's a summary. Colonies with fresh comb produced a greater area of brood, a greater area of sealed brood, and heavier individual bees. Interestingly, colonies on old comb had a higher survivorship of brood, but as the study pointed out, that really is not a reason to keep old comb around. To quote the authors, "it is possible that the economic savings of using long-lasting comb may be offset by deleterious effects of old comb acting as a biological sink for toxins and pathogens or as a physical constraint on larval development."

Well, that's it in a nutshell, but here are a few more tidbits from the article that I found especially interesting.

On Age of Comb

The article indicated that the combs used in the experiment were of unknown age, but they "were dark and heavy as typical of combs one or more years old." [Bold face is mine.] OK, so maybe some  or most of the comb involved in the experiment was really old, but some could have been only a year-old. So I feel like my decision to cull 1-year-old comb isn't so crazy (or wasteful) after all.

On Brood Production

  • Old comb harbors numerous toxins and disease-causing contaminants such as nosema and foulbrood, which are spread from colony to colony by infectious wax. The queen may avoid laying in these cells.
  • Old comb may also be permeated with brood pheromones that can inhibit egg-laying because the queen perceives the cells to be occupied.
  • "Bees prefer to store honey and pollen in cells that have been previously used for brood rear-ing. In the wild, as a colony grows and continues to add new comb, brood rearing gradually shifts into this new comb and the honey is stored in the old brood comb." Actually, I thought this was interesting because all the books say that you should add empty bars between the brood and honey areas to keep the bees by the entrance and honey in the back. I've never found this to work for me. My bees just keep moving the brood further and further toward the back and storing honey in the emptied nest. Now I know why!
On Brood Weight
  • The cells in old comb are smaller than in new comb. As a result, the bees that are produced in old comb don't grow as much as bees in new comb. In fact, "Diminishing space may force larvae to moult to the non-feeding prepupal phase prematurely, causing nurse bees to cap the cells before larvae have developed maximally."
  • In this study, bees raised in old comb averaged 8.3% lighter than bees raised on new comb. However, other studies have shown that bees raised on new comb can be up to 19% heavier than those raised on old comb. It may not sound like much, but put it into human terms. Let's say an average woman weighs 140 lbs. A difference of 8.3% - 19% is 11.6 - 26.6 lbs. If a normal, healthy 140-lb woman lost 20 lbs, she'd be pretty unhealthy.
On Brood Survivorship

  • This is the one area in which old comb sort of outperformed new comb. Because comb absorbs and retains pheromones, the authors hypothesized that nurse bees may have been more stimulated to care for brood in old comb.
  • However, this performance was qualified because although brood in old comb was more likely to survive, colonies with new comb produced far more adult bees. This is probably due to the sheer volume of brood produced in colonies with new comb. More eggs are laid and more brood is sealed in colonies with new comb. (See table before.)
  • Although more brood survives in colonies with old comb, the number of adults in colonies with old comb was still lower. At least 35 different contaminants in wax have been documented. These contaminants may cause a high mortality rate in adult bees. Additionally, it's possible that returning foragers have a more difficult time locating their colony as contaminants may mask the hive's signature scent.

What do you think? How long do you wait to cull comb? Have you observed any differences in colonies with a preponderance of old or new comb?


  1. Interesting post. I have started a thread on biobees here : to discuss it.

    I am happy to continue the discussion in either forum or both.


  2. OK, I have quickly read the original article and here are my initial thoughts:
    - first, there is a reasonable argument about replacing comb, particularly when you live in an agricultural area where pecticides, neonicitinoids and other nasty things are used on a regular basis
    - second, this article provide no useful evidence for natural beekeepers one way or the other. If you look in the methodology section, they started from packages, they treated with various chemicals, they fed with sugar, they started with potentially contaminated foundation, and then they only ran the experiment for 28 days !

    I have also looked up Oconee County, Georgia. Apparently it was ranked the "third-best rural county to live in by Progressive Farmer magazine in 2006". Not necessarily a claim to fame, but it might well be that the older comb was contaminated by chemicals used in the average US farming environment, and that therefore the results do not generalise to other environments.

    I have already mentioned that the experiment only lasted 28 days. I would also challenge some of the evaluation criteria. Why is the amount of brood created in the first 28 days important ? Why is the total weight of brood in the first 28 days important ? Small bees are good, since it means that the varoa have less time to breed. "Survivorship" may be an indication of this, although I would guess that the interaction with varroa is not apparent until a lot longer than 28 days.

    While not fundamental to the study, some of the comments about white comb being better and propolis, fungus, bacteria and other stuff being bad are very anthopocentric and not at all backed up by any evidence.

    My opinion is that in a natural environment, there is a postive interaction between new comb, old comb, wax moths, and all the lovely propolis, creepy crawlies, fungus and other stuff in the hive that is best. So in environments close to this, we should leave as much of the old comb in as we can. But many modern environments, particularly rural environments, are nothing like this. In those environments, it might make sense to take out old comb because all the poisons in the environment collect in the old comb.


    1. Hi, Adam, Thanks for your thoughtful remarks.

      For the most part, I think the methodology makes sense. Packages may not be ideal, but I can see how they were trying to equalize all the factors. However, like you I would have liked to have seen this experiment run longer than 28 days. I don't know why they stopped.

      Like you, I believe that hives are complex organisms that requires bacteria, yeast, etc., and there is a synergistic effect that takes place between all of these elements. Without bacteria, yeast, even viruses, etc., the colony is not a balanced organism.

      On the other hand, I've watched my own bees progress over the course of years, and I've noticed that my queens prefer new comb to lay in (common knowledge to many beekeepers), and the bees prefer to store honey in old comb. So I really don't see the point in saving old comb for the queen to lay in, especially in a TBH when the hive is not expandable anyway.

      Also, I agree with you that many modern environments are not natural environments. I'd go so far as to say that most modern environments are not natural environments. Certainly not in my suburbia where neighbors and businesses are dumping fertilizers, pesticides, herbicides, fungicides, etc. all over their lawns. Plus, there are all the chemicals that people inadvertently dump into the environment just by driving and heating houses. I read a study once about the levels of toxic/petroleum-based chemical on plants located near roads. It was through the roof. Yet that's the kind of environment I live in. So yes, over the course of years, I've noticed a consistent trend in TF hives with old comb to underperform TF hives that build new comb each year, and I think it does make sense to remove as much of it as I can. (BTW, there is obviously some comb carried over from year to year, but I try to minimize it.)

  3. I think Adam's final paragraph is key - there are very few natural environments any more. That's not limited to rural areas - suburban and urban environments are teaming with poisons. Gardeners in these areas use higher doses of poisons per acre than in agricultural areas. So, I think for hobbyist TB beeks, rotating out old comb is a good idea.

    My question is more on method. Every time I try to move out old comb, it usually has brood in it, or at least pollen/nectar stores. How do you go about moving it out of the hive? In the spring when the population is low, this might be a bit easier. I typically move drone comb to the back of the hive for honey storage, but worker brood comb always seems to have valuable stores in it when it's not filled with brood.

    I also have a problem in the spring when I'm trying to get swarms/splits started. I like to provide them with some (older) comb to jumpstart things, but then I'm in the same position where they are still using it and don't know when to remove it.

    1. Thanks for weighing in, Don. I agree -- Unless you live in some incredibly remote area, it's really hard to find a natural environment.

      There are a couple times during the year when I remove as much old comb as I can. When winterizing, I'll pull any empty combs and melt them down. If we get a freakish warm day during early spring (about late Feb or March for me), I'll go in again and remove any empty combs.

      One of the weird things about my bees is that they really don't follow the rules regarding where the nest/honey should be. In early spring, the nest is near the entrance, but as the season wears on, and I add more and more empty bars in front of the honey bars, the bees build new comb and move closer toward the middle/back and start backfilling the vacated combs in front. I used to keep swapping them around, but I gave up on that a few years ago. Now I wait until after the spring flow has ended in order to prep the hives for fall by moving the brood back to the entrance and the honey to the back. I put the oldest combs all the way at the back so they get harvested. (Hmmm... Maybe, I should try just overwintering a colony with the brood at the back and honey at the front...)

      During the spring flow, if I notice any old brood combs or drone combs during an inspection, I also move them toward the back of the brood nest so that they're still part of the nest and can be cared for, but they're next to the honey area, so when they are vacated, the bees can fill them with honey in the fall.

      This year, I tried something different with Elsa hoping she'd keep most of her brood near the front and honey at the back. I started inserting bars at the front of the hive between the brood and pollen bars. It only sort of worked for awhile, then the brood nest started moving toward the back again. I have to assume they know what they're doing better than I.

      Like you, I also provide my splits with comb to jumpstart things. I just treat it like any other comb in the hive. If I see it getting dark, I rotate it to the back of the nest and remove it whenever I'd normally remove old comb (Winter, early spring, or part of a honey harvest).

    2. Julie and Don are both agreeing with each other, saying "Unless you live in some incredibly remote area, it's really hard to find a natural environment". And then using this to explain why they do a lot of comb replacement.

      Well ... I live in suburbia in North Manchester, England. I sometimes label my honey "M60" honey because I can guarantee all the honey in the jar has come from within 6km of the M60 motorway which encircles Manchester :).

      Of course this is not an unpolluted environment. But relatively speaking, because there is no large scale agriculture near by, and there is quite a lot of green belt, including the park where some of my bees are, it's not that bad. It is certainly not as bad as it is in the countryside where crops are grown on a large scale. There is quite a lot of forage, and it is generally speaking not polluted with fungicides, pesticides and neonicitinoids.

      I don't do comb replacement ( and in some of my hives, it would be an impossible operation anyway ). I do leave old comb in hives as a swarm lure, and I find that most hives where the colony has died out are re-occupied the next year as a result.

      Barbara on biobees - who if you read her post is only now considering a comb replacement policy when she has a colony reach 5 or 6 years old, and this is after many years beekeeping - does live in the countryside, but by and large it seems to be grass fields for livestock, so she too has a *relatively* unpolluted environment. As she says, she has a lot of very old comb in her hives and they are very successful and long lived.

      I'm not saying your observations of your own hives in your environment are wrong. But I don't think it should be advocated as a general policy.

    3. Adam, I'm glad to hear that your hives are doing so well. I'm very interested in Barbara's situation. Perhaps there is an environmental factor at play. I also wonder what type of hives she has. It may be that she keeps something expandable like Langs or Warres. Or it In that case, it could be that that ratio of old/new comb is such that it works for her.

      In any case, I would not presume to tell someone else how to run their own hives. However, I do know what I've observed and what works for me. Other people have to do the same.

  4. I'd like to post a link to Barbara's post on biobees. She has two very old colonies which are only now running out of gas. And there is an interesting observation about swarms' preference for old comb. The post is here :

    1. Thanks for the link. I'm aware that swarms prefer old comb. It makes sense. Something like 3 out of 4 swarms dies within the first year, and building a new colony requires a lot of resources. So if they can find a cavity with old comb, then 1) it's a signal that the hole is a good home for bees and 2) they don't have to spend as much energy/resources building comb.

      On the other hand, I'm not trying to attract swarms. Plus, the space in a TBH is limited, so I actually have to reduce the tendency to swarm. One of the best ways to do that is to remove old comb and give them empty bars so they can build new comb (which the queen prefers for eggs anyway).


Thank you for your comment! I can't wait to hear what you think!