i had this problem with my super nintendo controller, it was very strange, the controller was an off brand one and it was left sitting next to one of the name brand ones but the off brand one was the only one that got infested, and nothing else around had ants in it. there must have been over 1000 tiny ants in the thing and i have no idea why because i took it apart and there didn’t appear to be anything spilled into the controller. my solution was to put the controller into a ziplock bag and spray raid into the bag (not too much) to suffocate all the ants that came out and then i took the controller apart and thoroughly sprayed the rest of the buttons and the front and back plates with raid and then soaked all of the pieces (except the circuit board) in a sink of bleach and water. worked good, (not suggesting you do the same with your laptop) I’m posting this because i too am finding small ants starting to crawl out of my macbook unexplicably all of a sudden, i must have left it in the wrong spot one night.