The wasps eat the catepillers that chewed the roses. Really. It's normal around here to see a wasp carrying off a catepiller.

I raise monarch catepillers and it's a big job to protect them from the wasps. (But monarch butterfly catepillers only eat milkweed, of course, but I guess the wasps don't care which kind of catepiller is tasty, so rosebud-chewing catepillers probably make a similarly good meal for them.)

There are more buds chewed off today and I can't find a single caterpillar on my roses ... looked under the leaves too.

In your neck of the woods with warmer weather it could be a grasshopper or a number of other types of insects that chew.
It's not the wasps doing it though.

I contest that

I have seen several wasps slowly eating the top of my rose buds!

(Darlene - forgive me, not helpful I know, but I couldn't resist!).

Since my smallest cat Lizzy has not been in your garden, it can't have been her, but she does eat rose and other flower petals in my garden! We take our three cats out for walks in the garden on leashes every day. The other two eat grass, like proper cats. Lizzy likes flowers! Yesterday I watched her go up to a large Morning Glory blossom, and contentedly eat the entire thing! She loves to eat roses, too. She stops after one, and we don't spray, so I let her. It is so funny to watch! She is not interested in the poisonous ones like the foxgloves - cats have a lot of sense! Sometimes she just sniffs them - like Ferdinand!

Jackie

Katydids will slice rose buds so neatly it looks like it was done with shears. They are mobile and well camouflaged. The nymphs (immature stages) of the local species are green and shaped like spindly grasshoppers 1/2" to 1-1/2" long. The 2" adults have wings like green leaves.