The Ridge-saddled carpenter bee1 is omni-present on the hotels and nests on all section with a clear preference for section 2.
The males of this mall bee roam the in the vicinity and inspect the entrances to the bore holes looking for females.
The females are busy filling up the nests and are interrupted every now and then by a pushy male….
A close-up of the nest cover of the Ridge-saddled carpenter bee, which consists of resin with small stones pieces and other materials which makes it harder for Ichneumon wasps to pentrate the seal2.
The females re-use the nests of previous seasons and first clean them out completely. With her legs all food rests and rubble are removed and pushed backwards out of the nest.
There are many Ridge-saddled carpenter bees in the hotels and every now and then mistakes seem to happen where a female enters the wrong nest. Sometimes even arguments seem to occur and some conflicts seem to result in a competing female cleaning out an existing nest, like in the picture below.
References1 Peeters, T.M.J., H. Nieuwenhuijsen, J. Smit, F. van der Meer, I.P. Raemakers, W.R.B. Heitmans, C. van Achterberg, M. Kwak, A.J. Loonstra, J. de Rond, M. Roos & M. Reemer 2012. De Nederlands bijen (Hymennoptera: Apidae s.l.). - Natuur van Nederland 11, Naturalis Biodiversity Center & European Invertebrate Survey - Nederland, Leiden.
2 Breugel, P. van 2014. Gasten van bijenhotels. – EIS Kenniscentrum Insecten en andere ongewervelden & Naturalis Biodiversity Center, Leiden., pag: 246