All the colonies survived into March but Clarissa did not last into April. Since that happy day of observing traffic from all the hives, we had been uncertain of seeing any from her. Confusingly we would see foragers come to the entrance, flit about a bit, and then suddenly dart off to enter Beatrix or Dorcas. A very few may have entered but we were unsure. The other hives definitely had traffic.

Three Sundays ago we were sitting on our bench, watching bees at work, and finally lost patience. Without suiting up we impulsively opened Clarissa and had not a single bee come to question our intentions. Grabbing a hive tool, we somberly poked through the combs. She resembled a typical winter varroa death as described in this article. [Edit: 2021-Apr-23 Changed to link to a newer version of the article per comment from its author.] Looking at its points in detail:

  1. The colony was big and looked healthy in the fall.

    Yes, it did.

  2. A lot of honey is left in the top supers.

    Equivalently for our horizontal hive, the combs furthest from the winter entrance are full of honey while those nearest have just bit at the corners with slightly moldy cappings.

  3. The cluster is now small, maybe the size of a softball.

    Smaller. And moldy.

  4. There are hardly any bees on the bottom board.

    Definitely dead bees on the floor. Not as thick a carpet as we have seen but more than “hardly any”.

  5. Near or just below the cluster is a patch of spotty brood – some fully capped, and some with bees dying on emergence (heads facing out, tongues sticking out).

    Nearly no brood at all. We did see one cell where the occupant had just cracked open the capping and expired.

  6. If you look closely in the cells around the brood, you will see white crystals stuck to the cell walls, looking like someone sprinkled coarse salt in the brood nest.

    In past years before we took varroa monitoring and treating seriously, we would see such small crystals in many cells. We thought they were sugar until we learned that they were guanine from varroa waste. We see some such cells this time and more with large blobs. Incontinent varroa on diuretics? Could they possibly be larvae that had gone through a few freeze thaw cycles? We have not read of such a thing but the color and volume of these deposits do not quite match varroa poop descriptions or our previous experience.

  7. You don’t have records showing that varroa was under control.

    And there is a bit of a puzzle. We do have records indicating that varroa was under control except in Dorcas, not Clarrisa. We applied the oxalic treatment to all the hives anyway and verified that the mite count in Dorcas had declined to our target level. It is true that we did not check Clarissa’s mite count post-treatment but it had already been fine pre-treatment.

So Clarissa may not tick all the boxes for winter varroa death but it still seems the likeliest explanation at this point. And our fault yet again.

Long time readers will recognize the significance of the black border. Yes, we are once again bee-less. We long suspected that Beatrix and Frankie had died when we saw no flights on the few, isolated, warm days but Dorcas still reliably produced clouds until recently and we had been counting on splitting her to repopulate our beeyard.

We began this warm weekend by opening Dorcas and found moldy but largely empty honeycomb without any sign of varroa crystals in the cells. As we cut away and discarded the combs an increasing number of neighborhood bees began arriving to mock us and clean up the dribs and drabs of honey we were spilling. We should have looked for mites among the dead bees carpeting the floor but forgot. We are poor coroners in the throes of grief. Our suspicion is that she died of starvation. We did pop in a feeder a few weeks ago but it was too late.

Moving on to Beatrix we found, except for the carpet of dead bees, a textbook case of winter death by varroa. A formerly populous colony reduced to a tiny cluster among much honey and the telltale varroa crystals in empty cells. Not entirely unexpected. We have learned the importance of a late season oxalic treatment but life kept us from applying it last year. The honeycombs were quite moldy. We would be denied the honey harvest consolation of our previous deadouts.

Finally in Frankie we managed to find a little honeycomb that was not moldy along with another dead bee carpet. No varroa crystals. Our guess is that she simply had not grown large enough to keep herself warm in spite of all the insulation we added.

We found a few, dead small hive beetles in Beatrix and Frankie. The bees apparently kept them under control until they could die together. No sign of wax moth either. None of the combs were slimed by either pest.

The bags of silica gel were saturated and we had the passing thought that they had, perhaps, been less effective than the wool we had used and the bees got damp. But then we considered that the bees themselves manage to keep air circulating to control humidity and, just as the mold appears after there are too few bees for this task, so too might the bags have become sodden after most bees were dead. A result, not a cause.

In our misplaced confidence we did not order any just-in-case nucs or packages so it is not clear where we shall get our bees for the season. Perhaps another swarm will visit our apple tree but we can not count on that. At least we will be able to perform various intended repairs and modifications on empty hives without troubling any stinging residents. Not exactly a silver lining.

 

 

April is the cruellest month, beeking.
Sisters on the dead floor, lying.
Wax comb and honey, molding.
Dead hive with spring winds.

And there we shall stop mauling T.S. Eliot to report that Clarissa is dead. A mere few weeks ago all three hives were flying on a brief warm day, bracketed by weather too cool to be out, leaving the bees cowering and clustering inside. Then last week there came a few days of greater cold, freezing nights, and fierce, blustery, undying wind causing much disarray including the removal of Clarissa’s front insulating panel. We do not know how long it lay unnoticed with the wind striking full on her unprotected face. We taped it back up in haste but it would not stay. It was pulled off again. We again reattached it more securely and the wind eventually died down.

Then Wednesday was a very warm day and two hives were flying. Not Clarissa. Thursday was even warmer but she still showed no signs of life. We opened her up and found a half inch deep layer of moldy bees over the entire floor. As further insult even the plentiful honeycomb was moldy, depriving us of the one consolation previous deadouts gave us.

So what killed them? The mold comes afterwards when there are not enough bees to circulate the air and control humidity. In the past we have readily blamed cold when varroa was the actual culprit. And it is true that we were unable to give Clarissa the usual, late-year oxalic treatment. But those previous colonies had received no treatment at all, died in February if not earlier, and did not leave so many bodies. This time perhaps it really was the cold? So many bees, so much honey, and yet not enough warmth could be generated? Disheartened we bagged the dead bees and moldy comb for trash and closed the hive for a proper cleaning later.

She is survived (so far) by Dorcas and Beatrix, who is still booming with more bees than seems possible.

 

The warm Saturday (40°F/5°C) should have seen cleansing flights but there were none. Out we went to thump the hives with rubber mallet in hopes of rousting a guard bee or two or, at least, raising a buzz audible through our stethoscope. No joy at all.

Removing the roof from Beatrix exposed some mouse nesting material atop the eke, which itself was intact. Lifting the eke and opening the hive we found combs of plentiful honey and, as expected, dead bees, most on the floor and a lesser number in cluster. There was also a snugly nested live mouse, which we evicted. At least there was no sign of damp.

Disheartened and learning nothing useful from our comb-by-comb inspection we gave Clarissa and Dorcas the most cursory of examinations merely to establish that they were mouse-free and turned to Dr. Meghan Milbrath for professional help in conducting the post mortem on the other two hives. While she rightly warned us that it could be difficult to come to a specific conclusion for the reasons for a deadout, we were rightly certain that she could point out things we had missed and their significance.

The following Tuesday we opened Clarissa and Dr. Milbrath worked her way through the hive from the follower board towards the brood nest. The combs began with a good number full of honey. Then a few less full and with some uncured honey. Finally in the brood nest, a small cluster around the original marked queen at the top of the comb. And eggs! Also a small bit of bee feces. But her most critical observation was how many of the odd flecks of detritus on the floor were dead varroa. Dorcas showed a similar pattern with an even larger brood chamber. We had certainly been lulled into false security by the lore that says first-year colonies need not worry about varroa. While often true any colony with a lot of brood is vulnerable, even a first-year if it grows to strength quickly.

The scenario proposed by Dr. Milbrath as likely is that the varroa weakened and killed many of the winter bees, those produced at the end of summer. That alone could have doomed our colonies but the warm spell we had made things worse by prompting the queen to lay eggs. When the temperature again dropped the diminished colony could not re-enter cluster as it fecklessly tried to keep the new brood warm and was further diminished. In addition the uncured honey may have fermented and sickened any consumers. Finally the tendency to climb rather than move to another comb for food would work against such a small colony even if it were not stuck trying to protect brood.

To prevent a recurrence with the nucs we have ordered for this year our plan is:

  • Monitor varroa, remove drone comb judiciously, and be ready to intervene with gentle chemicals.

  • Apply a mouse guard of some kind in the fall since our single entrance hole is less inaccessible to the little rodents than we had thought.

  • Crowd the bees once the drones are gone, that is, be slow in adding topbars. This will encourage the bees to backfill and cure the honey nearest the brood nest.

  • Be less timid about working the hives in colder weather.

  • In winter add a spacer under the eke where food can be placed (candy board or honeycomb from the back of the hive) and spread top bars to allow access to it.

  • Improve ventilation by make holes in the styrofoam top of the eke. This would allow gentle diffusion of air through the wool batting beneath without risking drafts. Possibly add small upper entrances or vent holes to the hive body.

Some of these are leading us away from our inclination to let the bees manage on their own as they see fit but that has not been working out well for them.