postmortems & mysteries

CSI: colony postmortem

Here’s an exercise for all you hive detectives out there. Beekeeper Aaron Althouse from here in the Pacific Northwest recently lost one of his two hives. He performed a postmortem, took many photos, and wrote an analysis, all of which is posted below. Your task is to see if you agree with his conclusions or have another idea altogether.

I have my own opinion but I will wait to see what you think. This is a good opportunity, especially for new beekeepers, so see what a dead-out hive might look like. It is also a chance to see how a thorough colony postmortem is done.

Nice job, Aaron. Thanks for sharing!

Colony Postmortem by Aaron Althouse

Olympic Peninsula, Washington


One of my two colonies recently died out. I don’t recall exactly the last time I saw bees flying from the opening, but I’m pretty sure it was about 3 to 4 weeks ago, since I know I checked them after the cold snap we had about mid-December.

Last Wednesday (January 14) we had a brief respite from the rain and wind, and the sun poked its head out for an afternoon. I walked up to my apiary and looked at what was happening, and saw no activity in that hive, while the other hive a had small number of bees flying and moving about its opening. Expecting the worst, I went ahead and took the lid off and lifted up my moisture quilt box. I saw a number of dead bees on top of the frames, many of which seem to be in mid stride. Since I didn’t have a lot of time, I put the quilt box and the lid back on and waited for a dry day to do a more thorough investigation.

General Findings

  1. The wood shavings in the quilt box were dry as a bone. I did not see any sign of infestation or anything else that makes me think that some other creatures had moved into the hive.
  2. Looking down into my top deep, I saw what I refer to above, a number of bees on and in between the frames that look normal, except that they are not moving.
  3. I removed the (very heavy) top deep and inspected the bottom deep. I see a little bit of bridge comb as expected, and not much else. There are again a few bees here and there that look normal, but none are moving. I do see some evidence of mold, but that is likely not the cause of the dead out.

I broke down the hive and put in my wheelbarrow and wheeled it down to my garage where I could take a closer look without being rained on.

Frame Inspection

The manner in which I loaded my wheelbarrow meant that I started inspecting the bottom deep 1st.

Bottom Deep

  1. The outer frames have what I am pretty sure is pollen; some of it is starting to mold. It seems a bit wet. The frames are only partially drawn out.
  2. As I move to the next set of frames, I’m finding more wet pollen, this time with more mold, and good amounts of capped honey. I don’t think I see any brood yet, which is expected since this was the bottom deep.
  3. Getting into the 3rd or 4th frame, I see a number of uncapped honey cells, which are bubbling. My assumption is that this is “wet” honey that has gone to fermentation. At this point, I also see some cells filled with white goop that I think may have been brood.
  4. The capped honey is generally found on the section of the frame that would be away from the side of the hive facing the sun. I do not see the classic pattern of brood, pollen, and honey arc.
  5. I removed the rest of the frames and pulled the hive body off of the bottom board. I see what I think is about 1000 dead bees that are now mostly moldy. If I combine them into one group, they would probably cover about one third of the screened bottom board, one layer deep.

Top Deep

  1. The top deep feels like it is loaded with honey. It is heavy and awkward to move.
  2. The 1st 2 frames I pulled are filled with capped honey. There are a few bees on the frames, none are inside the cells.
  3. The 3rd frame shows a bit of cross-comb but nothing dramatic. There is plenty of capped honey and a number of empty cells. There is more of what I think is old brood.
  4. Between the 4th and 5th frames I see what I am pretty sure is the remnants of the cluster. It is about the size of a racquetball; way too small to be effective. It is on the sun-facing side of the deep body. There are bees in the cells and appear to be surrounding something. I’m pretty sure that if I dissect it I will find the queen. That particular frame has almost no brood or pollen, but does have capped honey on the far side. There does appear to be some capped brood right next to the cluster.
  5. On the next frame, I find lots of wet pollen, capped honey, and more of what I think is old, capped brood. I am not sure, because it is tan in color and the capped honey is white, but when I scratch off the capping, it seems hard as if it was animal fat or lard. I did not use grease patties.
  6. The 6th or 7th frame shows only one old supersedure cell, that does not have deep cells in it, so it may just be some burr comb.
  7. The remaining outer frames are filled with normal, capped honey.


  • My initial thought was that the bees starved. Upon finding bees in and around capped honey, I can’t say that this is a very good likelihood.
  • There was no significant moisture in the hive; it was dry except for some of the uncapped nectar that drained out as I was moving frames around. The bees do not show signs of infestation, Nosema/dysentery or foul brood:
    • They are not greasy or black.
    • They do not have separated wings or K-shaped wings.
    • They did not die with their heads in the cells; the weather was previously cold.
    • There no dead bees seen outside the hive.
    • There was no discernible smell other than the sweet smell of honey. There was a distinct lack of what I could determine as likely to be brood, capped or uncapped.
    • There are no brown or yellow stains all over the outside of the hive. It’s true that these could have been washed away by rain, but I have never seen anything like it and I walked by them on a regular basis.
  • Given the cluster size, I have to assume that during a break in the weather, the bees broke cluster and were caught in a sudden cold snap and were not able to regroup and generate enough heat to stay alive.
  • One other possibility is that the queen died unbeknownst to me and did not lay any brood, so the majority of bees died of old age and the remaining few that were there clustered around themselves in a feeble attempt to stay warm.

Click on any photo to see slides.

Editor’s Note: My own theory will be in the next post: “Last thoughts on a lost colony.”

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  • How big was the family going into the winter and how was the mite load. I’d expect the dead bees to be piled in the middle of the bottom board. They seems to be spread in an unusual manner, implying bees crawling all over the place as if maybe loaded with parasites. Even queenless bees will make a clump when chilled, so this is strange.

    Assuming no bees were carried out, the ‘dead” count does not look like more than 2 frames of bees. That will not take cold easily. Small clump unable to move certainly chilled and starved out. The mold on the frames implies moisture without circulations. The quilt box still needs heat from the colony to carry air up. If there is no heat……

  • Sorry for your loss Aaron, it’s never easy. That supercedure cell (which looks strangely sideways) has me thinking Aaron’s second hypothesis is correct. It seems to me that this colony definitely did not have enough bodies to stay warm, but did have sufficient numbers in the past to stockpile good quantities of stores. I’d guess that the queen died or swarmed late in the season, and the emergency queen that the remaining workers raised could not find a mate in time. Without new recruits the colony gradually dwindled to the point of no return.

  • Judging from the small size of the final cluster and the amount of dead bees on the bottom board (not many), my guess is the colony was too small to begin with and gradually froze to death. Just a guess.

    A mouse might have spooked them, but I can’t see any signs of mice in any of the photos. No comb or frames chewed way. No slivers of wood on the bottom board. No droppings. Plenty of honey, so they probably didn’t starve, unless they were too small to break cluster.

    At least he has plenty of drawn frame to work with in the spring.

    Here are two more postmortems I did — of a starved out colony and one with a mouse — with detailed photos and video for anyone interested in seeing it up close.

  • I am most anxious to see what you think. I have no thoughts – so look forward to yours and any others that are posted.

  • My guess would be that the queen died (or stopped laying) and the hive dwindled to the point that general housekeeping gave out (hence the dead bees, etc.). Given the lack of queen cells, it may be that she stopped laying viable brood a while before she died, so there wasn’t any opportunity to try to raise a new queen until it was too late.

    I’m curious to hear what other theories there are out there about this mystery!

  • A better photo of the clustered bees might show the classic example of a colony that died because of tracheal mites. Since the colony was not treated with grease patties and the few bees that are visible are laying flat against the comb I would consider tracheal mites as being the main culprit.

  • If this were in my area (zone 7 SW Oklahoma) I would say there is a possibility that mites killed many bees then they got so small (the cluster)they couldn’t keep warm and they froze to death. This will be an interesting subject. I am anxious to read the last line. I opened my hives today and found that I had lost a colony. This seemed to be a fairly strong colony in the fall. I had dead bees not too different from these except I found no cluster. In my hive there was no honey left in the comb. I think this had been robbed by another hive. I really don’t know how much honey they had when the last bee died.

  • Sure hate to hear of a colony dying. If the cappings on the frame where the colony finally died are raised, then the colony went queenless prior to clustering and they started raising drones as a laying worker, but I can tell on my screen. There is definitely a moisture issue there. Moldy frames of pollen are a sure sign that ventilation is a key issue. The bubbling nectar is another key sign of moisture as well as the moldy dead bees. It would be helpful to know if the queen was indeed not present? I would suggest taking the bee bread out and keeping it dry and feeding back into a survivor colony…this becomes rocket fuel for late winter build up. And of course get some venilation on the second colony, if it is set up the way as the dead colony, and stack the full deep of honey on top of the remaining colony for storage.
    Keeping bees can be tricky and has steep learning curves…but in time makes for a good beekeeper!!!

    • Bill – As a new [3 yr] beekeeper, I really appreciated your last line. I live in southern Indiana with wildly unpredictable winters and extremes in temp. I have had a terrible time getting my hives through the winter [0 for 2 this year again.] However, I do feel like I’m learning a lot and I live in hope that one year everything will click and I’ll be able to not only get them through the winter, but actually start a thriving bee yard. Thanks for the encouragement.

  • I lost my one and only hive too. From all I’ve read it says “starvation” is the culprit. My frames look exactly like the ones posted here in addition I have little bee behinds inside the cells. It’s as if they all froze in place. It has given me much worry and I am unsure of my skills as a novice beekeeper and am skeptical to try again this Spring.

  • Late Fall/early Winter queen failure, and/or starvation due to the bees getting themselves in a corner too far from food.

    Was the queen in the midst of that little clump of dead bees? There are too few bees remaining to support a queen.

    For a double deep going into winter, I’d expect the top deep to be still solidly be filled with honey/pollen and the brood nest in the bottom deep surrounded by honey and pollen but, perhaps, beginning to move up into the lower part of the upper deep. These frames seem way too empty for January.

    Would like to know what the last 2014 inspection showed in terms of the colony’s configuration within the 2 deeps – honey, pollen and brood nest.

  • As a first-year beekeeper you’ll have to take everything with a grain of salt but here is what I think of the given analysis:

    “Given the cluster size, I have to assume that during a break in the weather, the bees broke cluster and were caught in a sudden cold snap and were not able to regroup and generate enough heat to stay alive.”

    I don’t think a cold snap could happen fast enough for this to be a viable explanation. It’s not as though it was an 60 degree day and they were plopped in a freezer all of a sudden. Unless a majority of bees were outside the hive and unable to return I would think there would be enough biomass in the hive in general to moderate such temperature swings. Also, there were what seemed to be a lot of bees on the bottom board. Enough to make me think that with as much food as they seem to have they should have been able to make it.

    “One other possibility is that the queen died unbeknownst to me and did not lay any brood, so the majority of bees died of old age and the remaining few that were there clustered around themselves in a feeble attempt to stay warm.”

    This seems more likely to me. In looking at the pictures the lone supercedure cell makes me suspicious. I “know” that brood production slows to a crawl or stops during the winter but not seeing much / any new brood in January seems like they wouldn’t have much time to build up for spring if they waited much longer. So I’m not sure that the queen died, but perhaps she was a failing queen that the hive waited too long to replace.

  • I love post mortems! I’m interested in what everyone else thinks too! Please let me know what you think of my notes – and thanks for posting this challenge.

    There is no mention of what came before this inspection. What I’d ask if I were there in person:
    1) How much honey did the hive go into winter with vs what is there now?
    2) How big was the cluster going into winter? (population change from then til now?)
    3) what was the last mite count and when (did he count?) Did he treat? feed? add anything else to the hive? if so, when, how much?
    4) if dead bees are relatively “fresh” – were they greasy appearing? (I can’t tell from pics)
    5) did any dead bees have deformed wings? half bodies? tongues out? were there any newly emerged bees in the pile of dead?

    Some conclusions I’d make based on what was offered:

    -Based on pics/description – I’ll Rule out robbers and Starvation as THE cause of death.
    Why? Since the bees were observed alive in December – very likely wasn’t killed by robbers/fighting (death would have been in the Fall). Robbing could have been a factor/problem in reducing population size before winter, but having more info like estimated population change between then and now would be helpful. I’ll have to use other clues…

    – By size of footprint of uncapped honey – looks like the colony was sizeably larger at one point this winter…so I don’t think they went into winter as a small cluster. Rather, something caused them to die off slowly over time after winter started.

    – the position of the remaining small cluster (on the side and sunny side) tells me they were likely too small to stay warm and were seeking heat – which appears away from available food on that frame. Interesting.

    –Doesn’t appear to be a lack of food…no butts sticking out of cells and plenty of food left

    – the fact that there’s a cluster at all (vs just all dead bees on the bottom board) points me to say…

    Cause of Death: The simple answer is they froze to death due to small cluster size complicated by dwindling populations due to some other cause.
    Inquiring minds want to know… what made them too small? (what was the REAL cause of death)

    – No mention of if guano was seen on tops of cells – I’d look for white deposits on brood comb – if there, mites were likely a factor in reducing population. If dead bees were greasy appearing or deformed wings, then mites were definitely a factor, if not THE major factor in this hive’s demise.

    – Was nosema a problem? Would need lab test to confirm. Nosema Ceranae maybe – since there’s no obvious defecation inside the hive which would lead me to think apis.

    -The “lard” looking stuff is likely ivy honey that has crystallized.( I still can’t figure out why the bees put this away- I don’t see them eat it later (rusty??) I don’t think this is a contributing factor in the hive’s death, but good to note.

    That’s my 2 cents. Feedback??

  • Alright, I’ll throw a bone out there. I am a new beekeeper that just lost my only hive recently (I’m in Western Michigan). That cluster looks terribly small for a winter colony. I’m doing little more than guessing but it doesn’t look to me like there is honey near the bees. I think he lost the queen over the winter before there were any fresh eggs for them to work with. So I guess I’m going with the last conclusion he went with as the cause.

  • I don’t have an answer or even a guess, but I’m not sure I agree with “no significant moisture in the hive” if variables include “mold… wet pollen… more mold”

    Im curious to know what to do with those moldy pollen frames. Stick them back in another hive [assuming the cause of death was not disease]?

  • Of course this is just guessing. First I would try to send in a sample of the bees for an autopsy. I am guessing pesticide poisoning because of them dying all over the hive seemingly carrying on normal life. But then again the two unidentified objects are suspect just because I have no idea what they are.

  • Aaron,

    Sorry about your loss.

    My two cents worth would be that your experience with this hive is not all that unusual. I know I have seen similar dead-outs in my short 10 years of beekeeping. I suspect that the cluster became too small to be viable and froze. Why it became too small could be queen loss, Varroa infestation or probably other reasons. But something caused the population to become to small before the hive was lost.

    The hard substance found in some of the cells in the top box might be crystallized honey. All the other symptoms mentioned here are fairly common in my opinion.

    I’m anxious to read some comments from more experienced beekeepers.

    Nice photography. Very descriptive.


  • Hi Rusty,

    Greetings from northwest Wisconsin and thank you for a wonderful site. I will throw my two cents worth in. It looks to me that the amount of bees present in the hive are very few. I don’t think the colony was thriving before the on-set of winter, whether that was due to a poor queen or lack of one I couldn’t tell you. Lack of bees equals lack of cluster, no cluster equals not enough warmth for the brood to survive (if the queen is even laying) or for the colony to be able to move laterally within a hive, no brood equals no survival. The colony can still starve with honey stores in the hive, if the honey is unattainable for whatever reason. Either way I think the decline and eventual death was caused by a queen issue.

  • Looks like they lost the queen or absconded and left the hive to it’s own devices. The bees clustered may be remaining workers that returned afterwards.

  • I would be curious what the varroa count was going into fall, and if there was any treatment for varroa. I’ve been hearing about a lot of beeks having hives die off already this winter–usually hives starve out later in winter. One experienced beekeeper has put out the idea that maybe tracheal mites is making a comeback, due to decreased miticide use. Maybe we need to be sending samples of these dead hives off for testing. It seems tracheal mites most often kill off a hive in winter. It’s hard for me to diagnose, but I would lean towards mites–varroa or possibly tracheal.

  • Too few bees to survive the winter. Not enough dead bees to make a sufficient cluster. My guess is no queen. When I have lost hives in the past, there was always some of the wet pollen, mold. I have never known which came first, loss of colony or mold.

  • My guess is that there was poor ventilation contributing to the mold issue. The plastic foundation seems like it would inhibit moving around and clustering.

    We had two hives abscond and so were hoping to learn something from this too.

  • Hi Rusty, looking forward to reading your assessment of what happened. The mold inside the hive box bothers me but not sure if this would affect the health of a colony or not.

  • Observation from a first season novice in the UK…….

    1) Two deeps for a small colony? Was it a small colony that needed combining ahead of the winter? Seems like a big space, but was probably not the key factor.

    2) Was there any Italian blood in the queen…..and she started laying a few eggs during the warm days when there would never be enough workers to keep the brood warm plus to cluster and keep themselves alive.

  • I have lost three colonies this winter – same tale – plenty of stores, few bees and not showing classic symptoms of head-in-cell starvation. I too feel that they were just too few in number to keep themselves warm. I have made note to unite small colonies in the autumn in future.

  • I am most surprise at the authors reaction (non-reaction) to finding mold inside the hive. Is that condition usual in the Pacific Northwest?

  • Cluster was too small, in the cold the bees couldn’t stay warm enough to get to the honey and starved/froze?

  • I’m a fairly new beekeeeper and not aware of all the various diseases and pests. My best guess is that the queen died earlier. Aaron never found the remains of the queen? Swarming, perhaps. But it seems like the wrong time of year.

  • Sorry to hear about this Aaron – you sound like an excellent beekeeper, with great attention to detail and a caring attitude to your bees.

    When bees die overwinter I always wonder what varroa treatments were done during the year. You don’t mention if you have an open mesh floor (called unscreened floors in the U.S.) and if so what the latest varroa drop count was.

    Given the amount of honey in the hive, my suspicion is that varroa weakened the cluster until they were no longer able to maintain the correct temperature in the hive, causing the brood to die and mould to set in. But that is just a guess and I can’t see the photos too clearly on my phone. Nosema could also be another possibility – it does not necessarily cause the bees to have dysentery so there could be nosema and no outward signs.

  • Agree with his analysis and conclusion at #4. Other than the mold and brood, this sounds exactly like a hive I look after for a Nature Center near here. They had sugar cake (part-eaten) and honey near them, thus did not starve.

    What the meteorologists call “non-diurnal temperature pattern” – when it turns cold through the day, rather than at sundown – is on the increase and, I think, represents a serious threat to bee colonies. Don’t they depend on the sun’s angle to know when to fly home? If the temp drops while the sun is high, they may become too cold to fly.

    Wonder what we can do about it, other than keep sugar right above the cluster so they don’t disperse too far when it does get warm? We are in 50’s days, 30’s nights right now, warm enough for the Water Maples to bloom, but not for them to forage much.

    Aaron, Thanks for the pictures and thorough description. This kind of analysis helps us all to be better beekeepers.

    Corinth, KY

  • No mention of beekeeper’s fall mite count or treatment protocol. While he does mention no k wing, this is less significant as phoretic mites are feeding on adult bees when no brood is present (as would be the case in winter). K wing bees would likely have died out earlier in my opinion. Being just strong enough to fly away from the hive? Had the author mentioned mites or fall treatments/IPM I might have a different perspective. Admittedly, While on my mobile device, I did not dissect the analysis carefully. Instead, somewhat jumping to the conclusion that it was mites because this seems to be classic symptoms of a mite kill and mites remain the #1 reason for colony loss.

  • I believe the hived died out right after it was checked in mid-December.

    Reasoning for this is the amount of mold in the hive and moisture content. There was considerable rain during this period of time. Bees could not keep the moisture from accumulating because of the size of the cluster. It is possible that the visit in mid-December chilled the hive killing the capped and uncapped brood.

    Cluster was not big enough to handle to cold snap. Bees were located away from the honey. Cold snap prevented them from moving over to the honey stores. Had the cluster been large enough they could have moved to where the majority of the honey was located in the top deep.

    A cluster will not leave viable brood. Because of the size of the cluster, they couldn’t retain a large enough area to protect the brood. They stayed in place and died from lack of heat.

  • Queen failure maybe, but no indication they were trying to replace her? Lack of bee bread? Multiple causes and the cold wet weather just finished them off as the colony was too small to maintain any warmth.

  • Too bad the pictures won’t enlarge on my computer. It took me a while to figure out what the moldy pollen was. I’d never seen that before, and unfortunately I’ve seen quite a few deadouts. I guess it’s just too dry here in Colorado. Based on the pictures and Aaron’s description, I think he’s right about isolation starvation. But I will venture to say that varroa was also a factor. When I see so few bees on the bottom board, I figure the bees removed a lot of sick bees. I’m curious about #5 in the top deep. What’s the stuff he describes as fat or lard? The few times I’ve removed a larva or pupa, it was pretty liquidy.

  • Sometime Mother nature is “cruel.” Not everyone lives all the time. I would like to know if the queen was in the cluster. I am a novice, but venture that this was a weaker hive going into the winter. I look forward to more experienced answers.

  • I had the same thing! Just checked my hive over the weekend to find all of them dead. Word for word I found what you found. Although, I think I had to much moisture. some black spot where mold has grown into the wood on the inside. Found the queen. Around a small cluster about the size of a racquet ball as you did. So close to coming out of winter… Just a couple more weeks. Darn it!

  • As a second year beekeeper going into my 3rd spring I have learned to keep my mouth shut, but I a anxiously waiting to see if my opinion matches others. What a wonderful exercise. It made me go back to my training books.

  • Could it be that the honey had granulated and, like oilseed rape honey, become unusable to the bees, causing starvation? (That’s the guess of a first year at school).

    England is currently in a cold snap following many mild damp days. No activity at the hive but a quick peek under the crown board proved feed being consumed and lots of faces looking up at me! So far so good in my first winter….but a way to go yet.

  • How old was the queen?
    Look for the dead queen, if not found it is possible this is the result of a failed replacement.

  • These are just closely spaced queen cups, not supercedure cells. They are not drawn out to be called a cell. If one looks carefully two openings can be observed. You can find these cups throughout the hive. So definitely not a sideways supercedure cell. Aaron, could you find the queen in the midst of the dead in the comb bees? She is usually among the last to die. If she is there, you can rule out non-cooperative queen.

    Secondly, if quantity of bees is not adequate, the workers will regulate how many eggs are raised by the queen. I personally believe the queens are sensitive to the workforce abilities too. Just some queens are more optimistic about the future, and some are more conservative. So if the colony was small there was not going to be hurried brood rearing in December to correct things. They just hope for the best but get what’s coming.

  • Thank you everyone for replying. I’m sorry to be a bit slow on getting back to you, but I am on the road for work and won’t have a lot of time until I get back home next week. I will try to give some general comments about the common themes I’ve seen in the questions above.

    This hive was extremely strong going into the winter. It did not swarm this past summer whereas my other hive, which is still alive, did. The 2 hives/queens were new this past Spring, 2014. Carniolan packages.

    As for mite treatments, I did not do any, nor do I have a mite count going into fall/winter. I’m aware of the issues and will likely do more about them in future seasons.

    I have not dissected the cluster yet, but I will once I get back home, and will report back my findings.

    The reason I appear to not be concerned about the mold is because my working theory is that it happened after the hive died out. This may be wrong headed of me, but I have my reason. I live in a wet area and know that we have issues with mold and need good ventilation. I have a vented lid and as the quilt box shows, it was dry. I do use a screened bottom board as seen in the images.

    Other things I did not do (yet)
    • Add a slatted rack. Bought 2 of them; could not lift hives to place under – this season. Planning to once spring rolls around.
    • Add an eke or feeder rim under the quilt boxes – for feeding in case they need it.
    • Provide a wind block for the openings. I did reduce them but that may not have been enough.

    Thanks again all for your input. And a big thanks to Rusty for allowing me to share this on your site!

    • Hi Aaron,

      I’ve written a detailed assessment myself, but I won’t post it until tomorrow. I’m bogged down with jury duty, etc. Anyway, I’m impressed with all the replies and all the thought that went into them. This was a fun exercise, although I feel bad for your bees.

  • I’m in the same boat as Heidi. I’m a first year beekeeper and I lost my only hive this year. My cluster looked very similar to yours and like Heidi I had little bee butts sticking out of my frames. I have to say that the cold hit so fast that they weren’t able to get into a big enough cluster fast enough to stay warm and died from cold/starvation.

  • I’m with others who suspect Varroa involvement. I suspect the population was just low enough to be adversely affected over the winter and the balance tipped.
    Is it possible that the hive becoming cold and then warming caused the condensation after the bees were dead? The moisture could be post mortem.

  • Hi
    People are saying there is no dysentery, I can clearly see dark spots of dysentery on the top bars and side of box near the tiny cluster. Dysentery can be a symptom of any of the following, not just Nosema apis:
    Amoeba, Chronic Bee Paralysis Virus, Nosema apis, Poisoning, Late feeding in autumn, Granulated, fermented or under-ripe honey, Impurities in stores, heather honey, Hard winter so unable to go out to defecate,
    confined indoors while active (wet summer).
    If they had lost their queen in late autumn when they were a reasonable size, they would have become drone laying workers and there would be drones on the floor and in the cluster and seen in the brood, but that would not be the main reason for such a drastic reduction in population. In the UK the bees hatching in the autumn become long-lived winter bees not dying of old-age until March unless they have another problem.
    The final little cluster probably died of starvation but that is neither here nor there, it is what killed the rest of the bees that is important. The photos of the actually brood area are not clear enough to diagnose but it is likely to be a disease of some sort or sub-lethal pesticide effects. Many of the original bees must have died away from the colony as there are not really enough on the floor to account for a normal colony. Do not re-use the frames with stores without treating with acetic acid for a week and then ventilate thoroughly and do not re-use the frames that are dark and have been used for brood rearing at all. Virus is a distinct possibility and maybe Nosema (ceranae or apis) and this is transmitted by faeces and comb so it is not worth the risk, for a small investment of time and money it is better to start again with clean comb.
    With many years of beekeeping and most of the UK beekeeping exams under my belt I can say that replacing comb regularly and not re-using old, is one of many ways to keep bees healthy and prevent the spread of disease.

  • Interesting replies. Here is my 2 cents, but with a couple questions for Aaron. First, what was activity like near the hive in the fall? Were there a lot of yellow jackets? How many dead bees did you notice outside the hive during fall ? Did you notice any activity (or lack of) at the entrance during the winter?

    It does not look like the bees died of starvation. There are sufficient honey stores, but there are no bees in the cells head first which usually happens when they starve with honey stores available. As the cluster fails, the bees will focus on eating the honey in a single cell, but since it is too cold to move, they exhaust the food supply in the cell and die there.

    My best guess is that the colony had survived a yellow jacket attack in the fall, but was left with insufficient numbers to make an efficient cluster. They also went into the winter queenless; the queen was probably killed off during the attack in late fall, and they tried to raise a new queen but did not have enough time. Had numbers in the hive been larger, you would have noticed piles of dead bees on the bottom of the hive.

    You should also notice (on warmer days in the winter) dead bees that are removed from the hive by the caretakers. If it is too cold they don’t bother caretaking, but on days that are above freezing, I usually notice dead bees that have been pushed out of the hive to keep the entrance clear. When the bees are starving or freezing to death, the bees just pile up.

    The too long/didn’t read version: Your bees died of cold because they were unable to make an adequate cluster. This was compounded by the lack of a queen. The hive numbers needed to overwinter and the queen were lost in late fall during an attack on the hive.

  • I keep my bees in a wet climate and I find mold on the frames every year. The amount of mold on Aaron’s frames is normal for me and the bees have no problem cleaning it up in the spring, though it’s usually with empty frames, not honey frames.

  • Sorry for your loss Aaron. A great excercise and teaching/learning opportunity for us all. I was impressed by all the comments but saw there was little mention of that superscedure cell in the frame. Why were bees superceding their queen in Winter? Something went wrong with that original queen at some time, maybe during the Fall and they just didn’t have enough bees to keep the operation running. There should be brood in the colony at this time-there was none. It was a downhill fight. The little cluster of bees on the frame, were the “last girls standiing.” They try so hard to survive and we get to witness their last attempts.
    Very sad but that’s the way Nature bats.

  • Stunning similarity to the events played out in my apiary on January 18. There was one striking difference; I trudged uphill to the house filled with heartache over my loss to locate the address for the research center in MD and left my hive behind until the following day. Midday I headed back to the apiary with intentions of inspecting another nearby hive and collecting samples to be analyzed. In utter amazement, I stopped in my tracks and stared gape mouthed at the flourish of activity in and around the hive that had absolutely appeared by all measures to have been lifeless. I fed the bees and thanked the powers that be for the Lazarus-like miracle. I watched them joyfully for the duration of a cup of tea and pondered what I had missed during my inspection. I concluded that what really mattered is that nature is greater than I can even imagine.

    • Keller,

      This sounds like robbing to me. You should check to see if a colony is actually living in there.

      • That was my first thought. I did recheck the activity inside the hive. I do still have concerns about the overall health of this hive. I made the mistake of purchasing used wooden ware and certainly have learned a lesson about cross contamination. I plan to replace the dark foundation and clean my frames. I will also move the hive to a sunnier location.

  • Can’t wait for your analysis. I am a “NewBee” myself. Those photos look just like what I got into this morning. I had a 3 box hive that I thought was thriving. Upon further inspection, after I noticed very few bee activity, the frames and bee population looked just like the photos. The top 2 boxes were full of honey which I am extracting today. I saw no queen or brood. And the remaining bees weren’t too interested in protecting the hive.

  • I don’t think the quilt box worked. I haven’t read all the above but sounds like moisture and freezing.

  • Aaron’s situation is much like mine, except that I do have a very small handful of survivors, but I cannot find their queen or any evidence of egg laying. I see some spotty brood pattern and something else… Lots of chewed wax particles (?) I think. It looks like little flakes of light colored wax and it was all over the dead. I also have quite a bit of very dark capped….. honey? I also see what looks like bee poop, but not dysentery per se, just fairly solid, dark spots here and there, no drips. I cannot tell by looking at the dead whether they are diseased because they may have been dead for quite a while.

    My question is: Should I introduce a new queen to the very small number of survivors? Thank you so much for your help. And Aaron’s testimony is so generous ~ it was the only one I could find to fit my own description.

    • Christel,

      Such a small number of bees may not be able to support the brood raising necessary to get the colony going again. You may be better starting from scratch or combining your stragglers with a stronger colony.

  • Thank you for this gorgeous, informative site, Rusty. Beautifully photographed and cleverly written. What a treat! I realize I am five years after the fact, but a hive inspection today revealed a very similar situation here to what Aaron documented in his thorough analysis. Specifically, I am wondering what he did with all of his honey. Between two dead hives, I have 4 westerns fairly full of honey, with some intermittent mold growth. What is the best way to manage/store this honey for future use with new nucs coming in several weeks? (I have ruled out foul brood and assume it is ok to use with new nucs?)

  • To answer Stephanie’s question, I put the boxes in my garage and waited for package season to come around. Back then I’m sure I worried too much about the mold, old pollen, crystalized nectar not-yet-evaporated into capped honey, and so on. As much as I could I heat treated the boxes, bottom board, and other non-frame areas. The I let the new tenants do their thing for the new season. They know more about being bees than I do about being a beek. 🙂

    I’m glad this post still gets read… and Rusty – thank you so much for the site!