Adam and I went to check on bees the other day, and we found interesting things. Here he is with the 5 hives. Each hive started on April 2 with a queen and about 10,000 bees.
Here's a frame of pretty new comb, with lots of bees, busy at work. They are making drone comb. Drone bees (male bees for mating purposes only) are larger bees, so their nursery cells must be larger too. The drones born in a hive cannot mate with their own queen, however; they must go elsewhere.
Adam wasn't too worried about this hive movement. It's fairly normal, and he didn't really "lose" the bees in this hive; they just moved. Later, he can split the heavy hive where they moved to, and force them to make a new queen, and he'll not be any worse off.
The first dead hive, though, did concern him, so he inquired online at some of his beekeeper forums. They told him that that queen was probably also weak, and many of her bees left as well. Adam agreed with this, because he'd noticed that hive box was light-weight, and he'd switched places b/t it and another, heavier hive. (As the forager bees return at the end of the day, they return to a location, and if they bring food with them, they're admitted.) In this way, he'd hoped to strengthen this light-weight box. But the queen was too weak. Many bees left. And the house-bees who were left to care for the comb were not enough to maintain the temperature and keep the hive cool enough. Thus, they died from heat. That was the consensus on the beekeeper forums.
This is good news because it means Adam didn't lose many bees after all. And if these dead bees met their demise from heat, and not from disease, then he can use the hive boxes again, without fear of harming bees who'll live there later. Diseased hive boxes must be burnt.
Evidently, when one buys new hives, there's a period of time when the bees are not as strongly attached to their queens and hives as they are later, and bees will move around, looking for the best queen. My mother says Julia should write a story about the activities of bees in a hive. Sounds like an interesting plot already!