One of my all time favorite "hard scifi" movies is 1974's Phase IV available on Amazon. What I mean by "hard scifi" is it only takes a little bit of suspension of disbelief to really think it could happen. Think Andromeda Strain or Colossus: The Forbin Project.
The movie starts out with a simple explanation that some astrological event happens and scientists wonder what will happen to the planet. Something small does happen instead of something big. Ants. Ants become more intelligent. They begin to behave differently. Two scientists are tasked with studying the problem using computers and crypto analysis.
The movie is filled with beautiful macro photography of ants working against the humans. Stuff like infiltrating the AC so the computers can only work at night. Bringing bits of poison to the queen so the next generation of ants is immune. And finally communicating using geometry!