Really, in order to 'solve' your problem, you need to 'identify' it first. The bugs can be anything. Talk to neighbors. Maybe someone at the Municipal Office, like a Plumbing Inspector or something, knows what they are. (Bring one w/you.)
I don't know of any 'bugs' that eat cement. There's absolutel no nutritious value in it. I think they like the 'living conditions' there. If your system drips, which most do, maybe you can route it to another 'place' with a tilted-pan that has a hole at the low end. Or a 'slit downspout' or gutter, or something.
If your system is 'surrounded' by bushes and such or is shaded by trees, try to 'alter' the living conditions. In the vast majority of cases, by simply altering the conditions, you can 'fix' the problem. Raise the temperature or dry out the area can have a dramatic impact. As a general rule, I don't gro ANTHING other than flowers anywhere near the foundation. That's because bushes and 'thick' plants obstruct airflow around the house, thus, increasing the conditions that promote mold, mildew, and moss. Termites like these conditions too!
These are a few things you can do. I wish I had a direct answer for ya. My best to ya and hope this heps.