I found this "nest" inside a nest box that I was cleaning out in readiness for this spring. Can anyone identify it please?? The grubs I saw were between about 6 and 10mm long. It was noticable that in making the "nest" the insect/moth etc concerned had eaten onto the wood as there were many shallow "scoops" out that matched th shapes of the peanut shape coccoons. The basic meaterial seemsed to be like finely spun silk or whatever.
These are the cocoons of the Bee moth, Aphomia sociella. The female of this common moth lays her eggs in the abandoned nests of bumblebees and wasps, the ensuing caterpillars feed on the old comb, detritus, wax and any dead bodies of the former occupants. When they are ready for pupation they up and leave and pupate together in these masses. Could be that there was a Bumblebee nest in the nest box, or in a cavity or base of the tree- there will have been one very near at least.
Many thanks for that.... yes, bumble bees have nested within about 20 yards of this nest box. They nested under a garden shed (and probably on other places) but the nest box was about 10 ft high on a house wall nearby. It had not been used for about a year and was last used by Great Tits.