This video was made possible by two things. 1: A toggle save video feature, which I didn't have in the last video (hence filming my screen), and 2: Cake. Ants love cake, and giving the ant a little piece of something colorful means you can follow that instead of making your tracker insect-specific.
I am still trying to make the tracker more robust. I followed this guide by Adrian Rosebrock to implement a generic tracker than can except bounding box coordinates of what to keep an eye on. The idea is that you could use your neural network or whatever to identify the bug in just one frame, and then the tracker would handle subsequent frames (as opposed to looking for the bug in every single frame, as I'm doing with color in the video above).
But even if you give it the coordinates manually by clicking and dragging, the trackers are just too slow and dumb, and the ants are too small and fast. But I'm still trying on and off. In the meantime, enjoy the above ant footage, which I personally think is pretty cool by itself.