A female Passaloecus sp. closes up her nest in the bee hotel section 3 block 14. I suspect it is P. insignis based on the longer yellow labrum but the other characters are not visible in the photo’s.
She has spend a long time closing the nest and made numerous detours on and around the neighbouring bee hotels to collect closing material. The nest plug consists of resin in which al kinds of materials are stuck like pieces of sawdust. She would go to closed nests and remove material from the nest plugs.
References1 Nederlands Soortenregister