bakers i wasn't certain they had been sprayed.....being the beekeeper in the family, i thought maybe your sister in law would have called you when they saw bees coming and going? when i saw the honey dripping, i thought there's no live bees in there...interesting that there are no robbers? perhaps as you said, wax moth, or other pest moved in, but what caused the bees either to die out or move out? very curious.