Looks like one of the hives I put in the squash field swarmed. When I looked at it Tuesday afternoon, I only checked the super, and it was full of honey, but not capped yet. So I went over this morning to put another super on and decided to check it more thoroughly. There seemed to be little decrease in the number of bees, but there were no eggs in any of the comb. There was lots of capped and uncapped brood, even one and two day old larvae. I also found three nicely formed ripe swarm cells on the edge of a partially drawn starter strip I'd left in there. I couldn't find the queen, even looking through the hive twice.
How long does a queen quit laying before a swarm issues? They've obviously been planning this move for a couple weeks, given the age of the queen cells. But eggs were laid as recently as 4 or 5 days ago. Would they have swarmed 2 or 3 days ago? Or could it be the swarm has yet to issue, even though I didn't find the queen?
In another hive there, I'm fortunate not to have laying workers. The hive has been effectively queenless since swarming around May 6th. I spotted a skittish virgin queen in there in mid-May, but she must have failed to mate or otherwise got lost. There were no eggs, brood or queen in there when I checked Tuesday. I put a couple frames of eggs and brood in the hive, and sure enough, there were queen cells forming this morning. I put another frame of brood and eggs in, just in case I might have damaged the cells by pulling and tipping the frames when I looked. I'll leave them alone now for a few weeks, knowing the hive will requeen itself in that time -- and have several thousand extra young workers emerging, to boot.