It is. Is it an artificial intelligence?
Well, I'm inclined to call a termite mound an artificial construct created by termites, and a beehive an artificial construct created by bees. If an ant colony is an intelligence (which I'm not as confident of as you sound), it seems no more problematic to call it an artificial intelligence created by ants.
Serious question. No single human being can build a nuclear reactor, land on the moon or calculate pi to the billionth digit, but humanity can. Does it qualify?