Yaeh, the fact that the capsule appeared undamaged is odd. I can think of two scenarios.
1. the cork bark was infested before being placed in the bottle or
2. (duh), the insect got in after the capsule was sealed, but didn't damage the capsule in doing so.
In doing a little research, I was surprised to find that the cork-tree genus Phellodendron is extremely resistant to insect damamge and that there are very few insects that naturally attack it- seemingly ruling out 1.
2. is possible if an adult beetle inserted an egg in one of the tiny perforation often present in foil capsules and the larva munched away until it got too big to get back out. It is possible that one of several different dermestid species might do this, but it seems unlikely- we'd hear about it a lot more if it was common.
I dunno- it's still something of a mystery to me. Was the recovered insect an adult, or still in the larval stage?
And as an aside, I first tasted port as a senior in college in my wine tasting class. The very first time I smelled the stuff (and forever afterwards), my immediate impression of the smell was "pickled bugs". No kidding- the stuff smells very, very similar to a jar of alcohol packed with insect specimens and left to sit for a year or two. I pointed this out to thebuggal, and it has permanently turned her off to port, the smell was so similar.
This is very unfortunate for me, as I've developed quite a taste for the stuff, even if it does smell like pickled specimens!
I never drank anything stronger than beer... before I was twelve.- W.C. Fields