The Chelostoma rapunculi  females are extensively using the bee hotels for nesting.
Every year the numbers increase with a current peak in 2020 when numerous specimen were active.
The nests are closed with sand fortified using small pieces of stone. Nectar and possibly saliva glue the components together .
References1 Nederlands Soortenregister
2 Breugel, P. van 2014. Gasten van bijenhotels. – EIS Kenniscentrum Insecten en andere ongewervelden & Naturalis Biodiversity Center, Leiden.