Consider any viral infection in humans, a virus hardly even being an organism, that cause behavioral changes and forces the human to seek out large groups of fellow individuals (hospitals), only to involuntarily spray them with bodily fluids (vomiting, diarrhea).
And it isn't true that there aren't more of the fungus, like the article claims. Planet Eart clearly states that there are thousands. And I believe that an ant has a fairly simple cortex, allowing simple chemical influences to make it go up, left, right, to the sun, bite, etc.
When you have unlimited noise and only select the bits that makes for a good breeding ground for a fungus, anything possible that CAN happen, WILL happen. See - Murphys law accurately describes the principles of life!