The buzz on buzz

The term "buzz pollination" is new to me. It's used in this article praising native bees for their unheralded work among the flowers. I've always known a lot about how they pollinate, but never this expression. We always keep all sorts of plants just for the birds, the bees, and the butterflies in all their stages. I have never been able to find out what are those very large, iridescent and metallically blue insects. I've always thought that bumblebees are hairy, but I don't think that these are. Some insects permit a close approach, but these don't. Perhaps they're some sort of beetle. They're very large, with a large and rounded thorax and abdomen, as I recall. I haven't seen any yet this season, although I have seen those very big red wasps. I'm happy to say that we see honeybees throughout the year and that they don't seem to diminish in numbers, at least not in our yard.