UPDATE: Users all agree... Varroa. Thanks for the feedback.
This fall, I had three hives. Two of them seemed strong, but I was keeping a close eye on the 3rd as it was a caught swarm. I noticed that the 3rd hive was being robbed by yellow jackets. The wasps were trying with various degrees of success to get into the other two hives, but they seemed to be fighting them off. I added entrance reducers and hoped for the best, but at my next inspection, I realized hive #3 was not going to make it as there were very few bees in it. I'm hoping they simply left again to find a home more to their liking. The wasps were still hanging around, which I concluded meant they were cleaning out the hive. I broke the hive down and prepared the other two hives for winter. They other two hives were still being pestered by the wasps, but mostly they were focused on hive #3, the dead one.
Both of the remaining hives had nearly full honey supers on top. I am a rookie, but have over-wintered my apiary for four years without losses, relying on the bees natural instincts and leaving them plenty of honey plus granulated sugar on their inner cover. I went to check on them last weekend and maybe give them more sugar, but realized that both my hives were dead. I'm sorry I didn't take more photos, but here's what I observed:
1) No signs of excessive mite infestation. I do not treat the bees with anything other than powdered sugar for mite control and I'm pretty lax about mites, but looking at the bottom board and I didn't see a lot of mites.
2) I did not observe signs of diarrhea
3) There were some bees dead in the comb with their butts sticking out, indicating potential starvation. (See photo.) What is bizarre to me, though, is that they (likely) starved literally right next to capped honey (see photo.) I am wondering, if the wasps managed to raid the brood box and caused dead spots that they wouldn't cross
4) We also observed dead bees with their tongues hanging out, indicating possible pesticide poisoning. After researching pesticide testing, I decided it wasn't worth it as I think the bees have been dead for a while.
5) Most of the dead bees in hive #1 were on the bottom of the hive. In hive #2, they were at the bottom, but also in front of the hive (see photo)
The fact that all three hives were lost make me think that it wasn't actually starvation. It might make sense that one hive would starve with a full super of honey, but both? And losing the 3rd? It seems too much of a coincidence. Then again, I didn't pay much attention to the brood box frames and if it would cause the cluster to become trapped. The hives were located close to the property line. (They are in Long Island, NY) and it is certainly possible that my neighbor's gardener sprayed close to the apiary. It is common to spray for ticks, poison ivy and other weed control here. However, that is usually done early in the season, not in the fall. I also can't help but think the wasps are to blame.
What do you all think?
Dead bees next to honey.jpgDead bees on bottom board.jpg