This is a male specimen of an introduced species in North America. These bees are becoming extremely numerous here in Illinois - they are large and aggressive towards other insects competing for flower nectar.
This is a female specimen of an introduced (invasive) species in North America. These bees are becoming extremely numerous here in Illinois - they are large and aggressive towards other insects competing for flower nectar - in this case, the crown vetch plant - Coronilla varia, itself an invasive species.
I believe these bees are mating - the larger male bees are constantly harrassing the females, which appear to be more interested in gathering nectar. Once the male actually 'grabs on', so to speak, he may hold the female motionless for several minutes.
