Which Wasp

I decided to try and work out which species of wasp this is, feeding on the Ivy flowers in our garden. Having got so far, I have given up for now.

Apparently the first thing to do is to determine the caste. Queens are seen in Spring. And are larger. So these are either males or workers. I think they are males.

The second thing then is to differentiate the species, which involves a lot of detailed anatomical investigation (there are a number of species which look like this) and is made more difficult because of individual variability.

Anyway - it’s a wasp. And during a dry period on a wet, grey day it and it’s fellows were taking every opportunity to feast on the Ivy bounty.