Together with some colleagues at Aberystwyth University I'm currently working on a project to characterise the exocrine gland secretions of solitary wasps. For this we need specimens and I'm looking at the common species we can collect in sufficient numbers. The sting and head glands of these insects only yield tiny quantities of material so we need about of 20 specimens of the larger species (along the lines of Cerceris rybyensis) and more specimens of the smaller species. What I'm looking for are very large aggregations of solitary wasps where the collection of the numbers we need will not impact the population. I already have sites for Cerceris rybyensis, but any suggestions for sites would be most welcome and I'll keep you up to date with our work. I've read about enormous aggregations of Cerceris arenaria in East Anglia and wondered if anyone had information on these sites?
Philanthus triangulum is not of interest as lots of work has already been done on this genus.