I was on Pinterest the other day, searching out some fabulous thing or other, when I happened across a photo of ants running a chalk maze. Clicking through to the original article from the Examiner (you might notice one eyebrow raising if you could see me, and if I could actually raise just one eyebrow), I was informed that ants will not, or don't care to cross lines of chalk, and so if a chalk maze is drawn around them, they will move through the maze rather than crossing the lines of chalk.
C (age 10) informed me that wouldn't work. Apparently, back in her younger days, she used to draw circles around ants with her chalk, to try to trap them (they were playing a lot of Zoo Empire back then). According to C, her ants would act trapped and confused for a few minutes, but then they would cross the chalk, out of the circle, and continue on their way.
We proceeded outside to find the first ant we could (it happened to be on our very dilapidated back patio - which isn't really good for chalk, but good enough for our purposes). Just as C thought, when confronted with a line of chalk, the ant did at first act upset and confused - it even started out walking our quickly drawn maze.
But, after a few seconds it tired of the game, grew used to the chalk, and walked right across the lines.
So, it would appear, that while ants might be momentarily disturbed by a line of chalk (or just about anything) placed in their path, and it might slow them down - in the end, it won't stop them. Ants will, most certainly, cross a line of chalk.