How to randomize holes in a mesh, like with a particle system? I'm building a bush that has been ravaged by caterpillars. I am working with a set of leaves, see attached image, and some of them I have created holes in the mesh, you can see in the mesh which is selected in Edit mode. 

I'm trying to figure out a workflow to generate the holes randomly - sizes, location, shape - in the mesh. Thereby limiting the base set of leaves. I'm seeking a workflow similar to how you would add raindrops on leaves using a particle system: create a droplet; Particle: Hair; Render As: Object etc... 

Can you think of a clever method to achieve this? 

It doesn't necessarily need to affect the mesh itself, but just the transparency (transmission) for render. 

The answer to this question suggests a workflow using micro-displacements, that might be a good starting point ... not sure.  Maybe creating a texture with the holes, that can be UV mapped ... thinking out loud. Keep in mind the leaves already have a texture mapped onto them, and a solidify modifier with Subsurf Scattering in the material.

Grateful for any bright ideas you can share.



EDIT

An answer was offered to run a texture through the Alpha channel. It's close but not quite there yet. See the attached image for the setup. 


The Base Leaf Texture is connected to Base Color - this has been unwrapped using 'U Project from view and placing the mesh on the image in UV editor. 
This same image texture is used twice again with ColorRamps to influence Roughness input and Bump via Normal input. 
As per the suggestion, I created a black and white texture file of leaf holes and this connects to the Alpha channel. (My understanding is that Alpha works with 1.0 = White = Opaque / 0.0 = Black = Transparent, hence the black and white image).


You can see this sort of works. 

The issues:


This method is not random, the texture is the same on duplicates. (Might I perhaps use a larger file for the leaf holes and somehow manipulate it with an empty...?)
This method is indiscriminate on the leaf, I need to restrict the pattern of holes from affecting the stem  (Can this be done with texture paint - or weight paint - multiple textures onto an object? So the mesh can be unwrapped onto the Base Color image texture and the pattern of holes image texture for the Alpha channel be selectively painted? Can you explain how?) This still doesn't affect the randomness of the holes.
Finally there is an artifact in the cycles render, the 'holes' are dark transparent grey in accordance with the shape of the mesh rather than completely invisible. (See final attached image for the Cycles render).


Further clues are greatly appreciated. Sincere thanks for your efforts.
What about using the Alpha channel on the texture? Create a random noise texture (or any pattern you want) and plug it in the Alpha channel. I think that the effect should be believable enough.

I would then add a simple bump map in addition to that, so the corners of the whole are a bit smoothed.

EDIT:

So obviously you need to play around a bit with the generated textures, but this is the way I'd approach it. Here is a sample:



This looks stupid because I didn't use a leaf texture or the proper model, but I think it would look quite good on yours, and it's completely procedural, so it will be randomly generated automatically and you can define and keyframe the size.

I've added a small gradient so the leaf gets browner closer to the wholes (you could blend this with a nice brown leaf texture), and a bump map, so the holes don't have a completely hard border.

This is the node setup:



Hope that helps.