This time of year here they are coming in for water and any chance food they can find. I can coexist with them as long as they dont bite. I use Orange oil cleaner or Windex to distrupt their scent trail and kill the ones that have made it into the house. I prefer not to use insecticides myself.... Thats just me. We dont have fire ants here yet but if we did I would bring out the big guns.
Um if they scattered when the light came on .... are you sure they are ants? If they are not get that exterminator quick. Its also swarming season for Termites.... Have you found alot of little papery wings either outside or in the house? Termites are a similar critter in appearance... a little bit longer than an ant and Here in San Diego they are very dark brown.
If you can catch a few in a pill bottle to show the exterminator they will definately be able to identify it.
deb
I have an exterminator license although I have never done it professionally, got the license and for a variety of reasons decided to do something completely different.
These were definitely either ants or small aliens that look like ants and I know they are up to something. LoL