Maybe it’s the feeling you get because you might imagine the insects crawling on your feet, or you stepping on them.
Why do I feel the urge to cover my feet?

When I see ants, I get all jittery and I can practically feel them crawling up me so I start shaking. If I wear shoes inside though, ones I haven’t worn outside yet, I feel a lot safer.
I have this weird feeling at the bottom of my feet and I don't know why. I think it has to do something with my arachnophobia. Whenever I see small skinny things with multiple legs I freak out and I want to cover the bottom of my feet (especially the middle of my feet).