Hummingbird Feeder Ant Trap

This is my "Hummingbird feeder Ant Trap". All spaces inside are 1/2". The oil cup is filled with mineral oil. The ant cannot cross the trap without crossing the oil, a 1/2 inch wide pool, which they cannot do.

To my knowledge, not a single ant has crossed one of my oil cup barriers. This one is based on a design I used for my bee hive ant barriers. This one is different from the bee ant barrier in that it has straight sides. The important parts are the same, though. There is nowhere a