The ants go marching one by one!
They will no longer walk through each other. Perfect for using the ability "Mighty Roar" to create a line of ants to slaughter!
I have been trying to get this to work for a very long time. Today it just clicked and I was able to get the Physics 2D layers to play nice with each other. Huntsman Spiders, Venus Fly Traps, Worker Ants and HoneyPot ants all obey each others physics and/or layers.
Sometimes you just have to keep trying, even if it takes you months. Never give up. Revisit your ideas at a later time if you are getting frustrated. Your thinking may be different and you'll approach things in a new light.