While inspecting the roof of our country cottage barn preparing to replace the barge-boards I noticed some severe dry rot at the top. As I liked the perspective I took a picture. I did not realise at the time that I literal had a surprise waiting under my fingertips! (see lower left corner)
I broke away the little piece of rotten wood that came loose just before and to my surprise it contained three capsules, like little containers, obviously made from leaves.
Removing some more wood a line of in total 10 capsules was revealed.
Studying the wood a tunnel 8-9 mm wide and 40 cm long was found with one more or less concealed entry.
Not aware of what it was I asked my kids to have a look too. My eldest got some pointy knives and started to dissect them patiently.
The capsules where all the same: 12 pieces of identically cut leaves formed the outer shell. Inside an other “rubbery” capsule was placed containing a single larvae. To seal off a cap was placed. At first sight it looked like 1 leaf only but when picked up it turned out to be build from 5 identical round pieces of leaves. This cap was sealed with a plug of what appeared to be a mash of wood. Some of the capsules had larvae in them, some of them had not. In these capsules a residue was found that seemed to contain a load of pollen. In the capsules with living larvae the pollen was “missing”.

Many questions came up? Just a few of them: “How do these larvae get out of the tube?”, “Obviously not all capsules resulted in growing larvae, how do the living ones pass the non viable?”, “Where do these larvae get their oxygen from?”, “How is this creature able to count the amount of leaves used for capsule and cap?”(NB all capsules had the same basic count – apart from one that contained 8 layers in the cap), “How ever did this practise evolve over time to what it is today?”, “Did the creature that created these ‘capsules of live’ also create the tube or did it use the tunnel of a e.g. a longhorn beetle?” (NB Looking at the single entry point and it looking – to my layman’s eyes – as build for purpose I would not be surprised if the tube was created by the capsule maker itself.)

But last but not least “What type of (most likely) insect did create this wonder of nature?”

One of the neighbours, after some research, came up with the (Dutch) “Behangersbij” a specific type of bee. Its Latin name is – I think – Megachile versicolor. (German: “Blattschneiderbiene”) Apparently it uses the leaves of roses to create the capsules which is consistent with our observations (both from capsules and corresponding cut-outs from the leaves of our roses.

It is this type of little encounters that makes me marvel at nature’s complexity and diversity.