This is my first posting. I live in Oakland, CA and my neighbor keeps Bees and over the past year she has had a hive on my patio. I've spent many hours watching and listening to this hive of Italian "Blonds" which she bought from a bee breeder in Chico, CA. Since the hive was installed we have had a intermittent problem with ants. It seemed that the problem had been solved by installing a "moat" around the hive/ box. The box is on cinder blocks within a plastic pan of water.
The hive was removed from the moat when the ants gave up at the end of the summer. Even after the 1st storm in November there was no problem with ants. -That is - until the 2nd storm, which didn't occur until February (for those outside of CA. we're in the middle of a drought). The rain in February brought the ants back with a vengeance. The box went back inside the the moat. Cinnamon was sprinkled all around it, and I was on daily ant patrol. My neighbor used some "Ecosmart Organic Insecticide" which she had used in the summer without any ill effects. It consists of peppermint oil, rosemary oil, wintergreen oil, mineral oil, Polyglyceryl Oleate, and Sodium Benzoate.
This afternoon I went to check on the ant problem and it looked worse than the yesterday, when I bent down to rescue a bee that had fallen into the moat, I realized I couldn't hear any bees from inside the hive (there is usually at least one really loud one giving orders :) ). I also realized there were no bees coming or going from the hive. So I cracked open the boxes and saw no bees! They were there yesterday. A few dead bees inside the box, but otherwise just ants. There were no dead bees around the entrance to the hive or lying around on the patio either.
I watch the hive for around a hour. A few bees came by the hive, flew around it as if checking out the hive, then departed. Some bees came by to have a sip of the water that I keep nearby. I realized some of them were from another hive as they were a dark brown and larger (Russians?) rather than the small golden bees of our hive. ....Finally after around a half an hour a blond bee went inside, but she came back out a couple of minutes later, flew around the hive, went back in, then came out and flew away.
It's all so sad, a few days ago they were bringing pollen into the hive. Could the ants have brought something deadly into the hive? Could the moat have encouraged a fungus this time? There didn't seem to be any noticeable mildew. My neighbor is away for the afternoon & evening. I'm not looking forward to telling her that her bees are gone.
Sounds more like they absconded rather than collapsed/died. It is unlikely the ants brought anything deadly, and more likely that they harassed the colony enough that it figured life would be better if they just up and moved to a new location away from the infernal irritation of ants.