[Michael.N.]

Might be the glue, might be the type of wood- Birch? They really do seem to love Maple but not dry Maple. One thing I do know for sure is that they absolutely adore damp conditions. I used to house bash many years ago, damp cellars and under leaking baths was their favourite hunting ground. I even had to replace several joists in my own cellar because they had got at them - a severe infestation. It's a damp cellar and had little air circulation. I replaced the joists, put in 5 or 6 air bricks and everything has been fine since. That was over 10 years ago.
I remember removing a side bath panel for a customer and the floorboards were absolutely riddled with them. Further inspection revealed that it wasn't just the floorboards. The joists were also riddled with holes. So bad that it was a miracle that a full bath didn't land in the floor below. But it was just confined to the section under the bath, the rest of the bathroom and the other areas on that floor were perfectly fine. No evidence at all.
Probably the clue to this is how old Radios have been stored. I suspect many found their way to Cellars and outbuildings that are a little on the damp side. I know my father had dozens of old wooden radios in the attic and I can't remember ever seeing a cabinet that had woodworm.
The radios have gone but that attic space is now my workshop. I have never seen evidence of woodworm other than stuff that has been brought into the workshop. I've had active wood brought in on a number of occasions. I've even watched them exiting, seen dozens of the little blighters land on the walls. Not once have they gone on to infect my wood and there's plenty of unvarnished wood for them to go at!