A little while ago, a question was posted about sleep in bees. I wrote to a colleague at the University of Texas, Barrett Klein, who has done some work in this area. Here is his reply:
dear Dave Green,
I studied sleep behavior in a species of paper wasp and am currently conducting research on sleep in honey bees (Apis mellifera). Sleep has been well described for this species, and a preliminary look of some sleep characters was examined in some solitary cuckoo bees in Arizona. Aside from that the "sleeping aggregations" of male bees in blooms, etc. are mentioned or described in a handful of scientific publications. No serious research has looked at this phenomenon shared by a number of bee species, although it would be a good guess to suggest that what the males are exhibiting is sleep.
If you'd like to read some honey bee sleep work, feel free to peek at my abstracts, which reference a couple of key papers.
Faith B. Kuehn, Ph.D.
Plant Industries Administrator
Delaware Department of Agriculture
2320 S. Dupont Highway
Dover, DE 19901