InsectNet forum

Looking for an educated guess on what these are or were...
Got the books online with those stuck on them. First assumed those were clothes moths but I don't really have an idea. I read that pantry moths larvae like to chill away from food before they pupate. Can you guys tell if those pupa cases are new or they pupated long time ago? Could have they layed eggs on the books, if they damage books or could have infested my bookshelf while the books were sitting there?
I didn't actually see any living moths or larva.
Currently have placed trichograma sachets on the bookshelf.
Any other ideas are welcome.
Thanks alot!

These look like empty pupal cases. The moths have already emerged, and they may have emerged some time ago, probably even before you received the books. I suppose this was a good place to pupate, probably the larvae didn't eat the books as I cannot see any sign of damage, but I can't advise further.

Adam.

Adam, glad to see you're still here. I assume you and your collection survived the earthquake intact. How far are you from the epicenter?

Yes - quite possibly the empty pupal cases of Plodia interpunctella, or a similar species -

https://bug.news/blog/moths/indian-meal-moth/

58chevy wrote: Tue Apr 01, 2025 5:07 pm Adam, glad to see you're still here. I assume you and your collection survived the earthquake intact. How far are you from the epicenter?

You could say "shaken, not stirred", but yes I, my family, house and collection are all fine. It was the strongest earthquake I have ever experienced, the house was not damaged but water slopped out of the fish tanks despite lids so I had to mop up as my wife was out at the time. We had a power cut for over an hour, but otherwise no problems.

The epicentre was about 500km away from here and 1000km from Bangkok where a building under construction collapsed and there was other damage to buildings. Sadly 20 people are known to have died in Bangkok, but maybe another 70 construction workers are still in the rubble of the collapsed building.

Adam.

Glad to hear you're well Adam and thanks for the answer!

livingplanet3 wrote: Tue Apr 01, 2025 6:51 pm Yes - quite possibly the empty pupal cases of Plodia interpunctella, or a similar species -

https://bug.news/blog/moths/indian-meal-moth/

That's very helpful. Thanks for the link. I hope I can find similar pages for the other housemoth speces.
Question: 1. Can we say, despite apearance of pupal cases that there are no eggs and the books weren't infested?
2. Is this behaviour of cocooning away from food strongly asociated to the Indian meal moth only?

I wouldn't draw those conclusions.
Larva pupate where it is advantageous to them, where that is, could be anywhere.
There is a good chance that you still have moths, if the infestation came from your
items that have been indoors.
Insects leave when conditions are better elsewhere, or what they came for is no longer available.
Ants are the issue at my house, and while killing them is possible, it's easier to prevent them discovering the spilled sugar.

kevinkk wrote: Wed Apr 02, 2025 4:48 pm I wouldn't draw those conclusions.
Larva pupate where it is advantageous to them, where that is, could be anywhere.
There is a good chance that you still have moths, if the infestation came from your
items that have been indoors.
Insects leave when conditions are better elsewhere, or what they came for is no longer available.
Ants are the issue at my house, and while killing them is possible, it's easier to prevent them discovering the spilled sugar.

I actually haven't had an infestation still. Books came second hand in the mail with those empty pupa cases stuck to them as seen in the photos. I haven't even seen alive any moth or larva. I'm now trying to find out if I have to prepare for an infestation cause I really don't want to put any books in the freezer. And keeping in mind my wife's expensive wools. I actually already got rid of the books in the picture. I don't know if the larvae were just chilling there and bailed out before I got the books or there could have been other livig larvae that I didn't spot and that decided to dine on my other books. And if they even like to eat books could have layed some eggs on those second hand books that are shaken off still sitting on my bookshelf.

Given that information, I'd probably think the moths were there before you got the books.
If you had to, you could always use a sealed bag or container in the freezer, or with a fumigant.
There are a number of moth traps for indoors,as well.