A couple weeks ago, I started seeing these bees curling up their abdomens and showing off the pollen collected on their fuzzy undersides.
The picture doesn’t show it well, but the curling up of the abdomen is really conspicuous. Along with this curling up, I also observed, what appeared to be, aggressive behavior to others of the same species. Maybe they were defending a territory or particular flowers?
Doing a little research to learn more about what I was seeing, I found out that only leafcutter bees, members of the family Megachilidae, collect pollen on their abdomen. Also, a basic bee fact that I learned, in general only female bees will have pollen collecting hairs, or scopae. Only female bees need to collect and provision the nest with food. The food placed in the nest with the egg is called “bee bread” and is a mixture of pollen and nectar.
Some quick searching on Google scholar revealed some older papers describing foraging territory defense by male leaf cutter bees and defense of nesting sites by females, but nothing specific about the behavior I observed. I’ll need to do a little more research.