Answer:
The holes were formed from either.., bugs could have ate the starch and the polyethylene was not a deterrent?
It may be biodegradable because it is edible to bugs? I'm not sure that makes it completely biodegradable though.
https://www.livescience.com/58810-caterpillar-biodegrades-plastic-bags.html
copy and paste this link. Explains alot?