I'm trying to figure out what caused a CCD-like collapse of one of my hives.
Hive was originally the bees left behind after a swarm, but they had no queen, or the many competing left over virgins killed each very quickly. They killed the first Italian queen that I introduced, but accepted a Michigan hygienic queen.
But from the beginning the hygienic queen laid a bit off, laying eggs a bit randomly and the worker bees having to lengthen the new wax for the bees. That was okay-- she eventually had frames of well-laid brood.
After about of month of thriving on her part, we decided to treat for mites with hopguard. The strips were gone from the hive each time we came in to put more, or vigourously chewed. At the same time, we had a hive go queenless and start storing up much more honey than it seemed they should have.
On the third week of treatment, the hive was gone. Only two-three frames in the second box remained occupied, probably with a hundred bees or so. Some spotty dead brood were in frames throughout the first boxes. The queen was still there, clinging to the side of box two. She had about 8 spotty larva on the frame next to her. The hive was clean of honey. There were no dead bees anywhere to be found-- just a normal amount on the ground outside.
My current analysis makes me suspect that the queenless hive robbed their weaker cousin when they went queenless, but then my question becomes-- where are the dead bees? The second treatment of hopguard, I didn't see any unusually low populations of bees, but the bees were simply gone by week three. But why was this hive shredding a chewing the strips? I did see so much activity at that hive and thought the new brood was really helping things pick up. It's also possible some of the hive drifted to their more closely related cousins instead of stick with the only Michigan Hygienic queen in the yard, right?
Another possibility is the queen was somewhat subpar-- in fact, my local beekeeping shopkeeper suggested it was just a poorly mated queen and that I should pinch her. I left her in a single box with a robbing screen instead, and a frame of honey. Perhaps she was poorly mated, but if so, that means I should expect failure from another package queen soon, and my other package queen already magically disappeared. :/ This is news I don't want to accept. Also a bit mad that he sold us the packages with failing queens and the queens we requeened with also failed. :/ His solution is of course-- buy more queens. He never offers to replace.
I thought at first pesticide exposure, or hopguard caused absconding, but why didn't they take the queen? This now seems the least likely, as the other hives were fine.
What do you all think?