What I meant was when I shop for cat food I just grab any old bag. I don't have an allegiance to any particular brand.
Oh there's the problem. Ever hear - you get what you pay for? Try at least once, buying the most expensive food available and see if that makes a difference.
As far as returning to the same spot either there might be a low in that spot or there is a trace of something drawing them there.
Can you put the metal part in the oven at high temp to kill any trace or microscopic subjects that are drawing them to that area?
One other idea is can you line the bowl with wax paper and tape it around the edge and then see if they appear on top
of the wax paper or underneath the wax paper?
Also just to be clear - do these bugs appear everyday? Do the Cats finish the food in less than 12 hours?
Have you tried smaller amounts of food (but maybe more often if you want the Cats to have the same amount everyday) with
the same results?