Halictid bees Halictis sp.

Many of the holes at the college site appear to be the nests of halictid bees, possibly Halictis rubicundus. I observed them entering and leaving holes and feeding on Yarrow flowers. I also saw Philanthus capture bees—sometimes on the wing—sting them, and fly away with them.

Given their numbers at both sites, these halictids may be the cornerstone of these communities, serving not just as food for Philanthus (5), but also ants (6).