Every so often a fellow beekeeper calls and asks me to come take a look at a hive that has gone wrong. Below are my notes from one of those visits, written up the way I’d write a patient assessment back in my nursing days: what I was told, what I saw, what I think happened, and what we did about it. There’s a lesson or two in here for all of us.
The call
Complaint: A sudden (less than one week) drop in population, with an increase in dead bees and a “sawdust”-like material in front of the hive.
Location and weather: Swansea, SC. Mid-60s, overcast, light wind.
Equipment: 10-frame Langstroth, three boxes tall (two deeps, one medium), screened bottom board.
History: A new hive installed this season from a package. It had been doing well until a few days earlier. The owner inspected last week and reported “full boxes of bees.” She became concerned this weekend when she saw more dead bees on the ground and the sawdust-like material out front.
What I found
- An open feeder a couple of feet to the side of the hive. More bees were working the feeder than the hive entrance, and on leaving they flew off elsewhere. The owner told me a neighbor keeps several hives.
- Entrance: Little activity at the reducer (set to about a two-bee width). No fighting.
- The “sawdust”: Appeared to be animal scat made up largely of bee parts.
- Top medium: No bees on opening. All frames filled with capped honey.
- Middle deep: A cluster of roughly 200 bees. No queen seen. Three emergency queen cells on the same frames but away from the cluster. About 20 capped brood cells, no open brood. Queenless.
- Bottom deep: Partly filled with nectar that passed the “shake” test, so it was well on its way to cured.
- Screened bottom board: 20 to 30 dead bees.
- Sticky board (in place for an unknown length of time): a notable number of mites, a few small hive beetles, very little wax debris.
- Mites on bees: On about 25 bees gathered at the top of the cluster I could see 4 or 5 mites riding on thoraxes and abdomens. I don’t normally trust eyeballing bees for a mite count because most mites are hidden, so seeing that many in plain view tells you the real number was far worse.
- Capped brood: Pupae pulled from the remaining cells had been dead for several days and were drying out. No mites seen in them.
What I think happened
Robbing? With the neighbor’s bees around, my first thought was an abscond under robbing pressure. I ruled it out: there was no fighting or frantic activity at the entrance, no torn cappings or wax shreds on the bottom board, and the stores were intact.
A raccoon or other animal? The scat full of bee parts pointed that way. But raccoons usually scratch at the box and landing board at night to bring the bees out, and I found no scratch marks. The hive was also raised off the ground, which discourages raccoons because they have to expose their bellies to stings. My best guess is that something smaller, a toad, lizard or snake, was simply cleaning up dying bees in front of the hive. The lizards in my own home yard do exactly that and are a help to yard hygiene.
Yellowjackets: The owner reported more yellowjacket activity. I didn’t see any, but we’d had a couple of recent freezes. Another pressure on an already weak colony.
Varroa: This is the one I’d put my money on. Seeing 4 or 5 mites on 25 bees with the naked eye works out to something like 16 to 20 mites per 100 bees, and visible mites are only a fraction of what an alcohol wash would find. The Honey Bee Health Coalition suggests acting at about 1 mite per 100 bees in spring build-up and about 2 per 100 at peak population and late summer, so this colony was many times over the line. A mite load like that brings viruses with it, the bee population collapses, and what’s left dwindles away or leaves. That fits everything I saw.
What we did
- Reconfigured the hive, placing the box with the small cluster on the stand. I told the owner honestly that the colony was queenless and would not recover. She had no other hive to combine it with and didn’t want to shake them out, so we left them be, with instructions to save the comb once the bees were gone.
- Removed the boxes of capped honey for extraction.
- After extracting, the wet combs go outside for the neighbor’s bees to clean up for 24 hours, then into proper storage. We went over storage options (freezing, then sealed storage, or open, well-lit storage to keep wax moths away).
- Plan to restart in spring with packages installed on the drawn comb, a big head start.
Lessons for the rest of us
1) Don’t open feed next to your hive. An open feeder introduces your bees to every other colony in the neighborhood, and during dearth it helps robbers find the weak hives. I don’t think it caused this collapse, but it’s a stressor the colony didn’t need. Open feeding also passes viruses between colonies.
2) Measure mites, don’t guess. Do an alcohol wash (or sugar roll) of about 300 bees, roughly half a cup, at least once a month from spring through fall. A sticky board left under a hive for weeks tells you mites are present but not how many per bee. With several hives nearby, this owner should also expect mites drifting in from her neighbor’s yard.
3) Treat before the winter bees are raised. Here in the Midlands that means treating right after the spring flow ends and again in late summer, then checking that the treatment worked. By the time you see mites on bees with the naked eye, it’s usually too late.
4) Do your last deep inspection in early fall. Make sure the queen is where you want her (in the lower boxes) and check stores before any fall feeding. Then let them get their house in order. Remember, while we’re trying to help the bees, they don’t see it that way. To them, we’re just another pest in the hive.
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