Who could fail to find this little insect beautiful. It is only tiny, easily missed. Probably about 1cm in length.
It’s a ruby-tailed wasp (Chrysididae sp.). I’d like to say what species it is, but apparently they are difficult to separate unless under a microscope or you really know your wasps. It’s also known as a cuckoo wasp. And, yes, you’ve guessed it, it lays its eggs in the nests of other species, it’s a kleptoparasite. In this case it was on the hunt for the nests of mason bees and I can testify that this wall had a lot of nests to choose from.
The female looks for unguarded nests and lays her eggs inside. Once they hatch the wasp larvae eat the larvae of the mason bee and emerge the following spring.