There's apparently four items in the game that have no known use outside of decoration, various bugs in a jar (butterfly, bee, moth, torchbug, and dragonfly).

I just noticed that there's letters scratched into the underside of the cork lids, but they don't seem to make any sense as words, so maybe they're initials?

My best attempt at reading the letters:

Torchbug: ZWKT

Bee: DKT

Moth: MT

Dragonfly: JWT

Butterfly: Gld orPig (I can't be sure which side is up)

If you want to take a look at them yourself in game, the quick way is to use the additem console command. Type player.additem 1

ID numbers:
Bee: 000b08c7
Butterfly: 000fbc3c
Dragonfly: 000fbc3b
Moth: 000fbc3d
Torchbug: 000fbc3a

thats a head scratcher for sure

I've never seen bugs in jars..
are they put in by the player or do you just have to find them lying around somewhere?

I wanted to add a butterfly in a jar to my bookshelf but it wouldn't let me, can they be placed anywhere?

Only got the bee never knew there were others and now you mentioned it I'll be looking for the letters. Hope this topic won't get lost. Love these mysteries.

Very odd, I'll post if I find anything

Just drop the jar and drag it like a dead body. Hold down E to do so if your on PC. If your on a console i'm sure your just have to hold down the loot button and it will do the same thing

Thank you, I will try that.

I found my first bug at the lighthouse on the northern coast, it was the torchbug. After noticing the writing, I found the item codes at the UESP site and added the rest to see if they had writing, too.

I'd like to think that they're some kind of code or hidden message for us to figure out, but I'm betting they're something more mundane, like the artists' initials -- I'd have to pay very close attention to the credit roll to see if any might match.

can't you just rotate and zoom it in your inventory? it's a feature of the game

They're talking about placing them on shelves and stuff like that.

OT: My hidden Detective Fund can now be put to good use.

Could it be a riddle? A word-scramble? Initials? A code? Sheogorath [censored] with us? Small children doing things to annoy us, knowing we can't harm them?

So many possibilities.

They most likely mean nothing.

I found the butterfly one a while back, it's in an alchemist's shack, south(ish) of that little village at the base of high hrothgar.

as for the letters, well they are insect specimens, would make sense that the letters would be abbreviations of the locations that they were collected, do they match the names of any places nearby?
could also have something to do with the scientific name of the species, or perhaps it's leftover from whatever was in the jar previously?

You find them around the world.

The scientific name theory is a bit hard to belive. There are around 20,000 different species of "Bees".

Poking around elsewhere on the net, I saw some people suggest that the markings were actually runes, but the runic characters that I've seen don't match up that well.

The intrigue really reminds me of the days when people were trying to figure out how to use Kagrenac's Tools in Morrowind to become gods and hoping to translate the Dwemer books to do it.

As much fun as hidden messages and secret quests are, I still bet the real story is that these are simply people's initials.