What's Eating My Rose's Leaves

[Streetgardener]

Hey Everyone,
I've been working on saving a rose I discovered as I mentioned in a previous post.
http://www.helpfulgardener.com/forum/viewtopic.php?f=7&t=65013

It's starting to make a comeback but as the leaves started to develop, something has started munching on them at night. At first I thought it was the nocturnal adventures of earwigs since it would happen at night, but when I placed some traps out all I caught were a few Roly Poly bugs.
https://en.wikipedia.org/wiki/Armadillidiidae

I was wondering if anyone had any insight into what could be eating my little guy's leaves and how to possibly stop it.

Some notes: I'm in Zones 4/5 in Toronto, Canada.

Here's an image:

[Marlingardener]

I'm not arguing with you, but are you certain the damage is done at night? I ask because the damage looks like leaf-cutter bee (aka Mason bee) damage, but they are not nocturnal. Leaf-cutters take a bite out of a leaf, roll it up and use it for making nest cells. There are also leaf-cutter ants and leaf-cutter bugs (the bugs are small elongated ovals, bright green, and have long legs). If you see any of these they won't do serious damage to your rose, and with the exception of the ants, are pollinators.
I'm sure someone else will have a better answer!

[imafan26]

Beetles and snails will putholes in the leaves but both would munch on more than one leaf. If you think it is getting nibbled on at night you can go out with a flashlight a couple of hours after sunset. Look for slugs, snails and slime trails. If there are any beetles they usually feed for about four hours or so after dusk. You would see them in the air or on the plants. Roly poly are related to shrimp and they eat mostly decaying matter in the soil. They usually don't climb up on plants.