@yah: "And you gotta visit the trove at every session to enable that feature."

I'm almost a decade late but this does not appear to be accurate.
I just opened up the game, did not visit the trove, unlocked and solved some levels that I had never played before, that I could tell had moths (from the noise cue @jngyue14 mentioned), without collecting their moths, and then I went back to the hub and looked at the doors and they showed the "missing moth" indicators. So re-visiting the trove is evidently not necessary.

(Possibly what you said was true at the time but an update some time between then and now changed it so it's not.)

Thanks a lot!

Nice! Thanks! I didn't notice before, but if you listen carefully in these levels, you can hear small ringing sounds

Thanks, this is exactly the tiny amount of help I wanted.
Jeez, some of these levels, what a crazy person do you have to be to find em without knowing there's a moth to find.

Addendum: you gotta catch 15(?) moths to make the game start telling you which levels have a moth uncatched. And you gotta visit the trove at every session to enable that feature.

Pretty symbols. I wonder what they meant.

Присоедниняюсь к словам San_Ten .
Спасибо.

Спасибо. Только то, что я искала. Ничего лишнего.

Thanks a lot!