Due to the definition of life an ant colony acts and reacts like a life form. There is even a "Ant colony optimization" Example Algorithm...
Does this mean that the whole pile of ants, not its individual antz (sorry Z), counts as an single, more or less, intelligent being?
EDIT: If you need focus on the "less intelligent" side for an affirmative answer, do so...
A colony of ants exhibits more intelligence than a single ant. Intelligence emerges from their interaction (as you probably know from reading about swarm intelligence). Exactly how analogous this is to "conventional" intra-organism intelligence is open for debate, but an ant colony isn't generally considered a single intelligent being.
The ant colony optimization you link to mimics a natural system because that system happens to be surprisingly efficient at solving certain kinds of problems, but that doesn't necessarily mean an ant colony is as cohesive as single intelligent being.
A significant difference to a real living being is the time scale (and development over time) on which a pile of ants acts like a single intelligent being.
However, the same question can also be asked for fungi, where it becomes a serious biological question. My biological knowledge is a bit too limited to give a definitive answer here. I believe that the spores, which can generate multiple (visible) mushrooms, count as a single intelligent being. And I think that they count as a single being, because they really are a single being from a biological perspective, whereas a ant colony is not.
There are at least two definitions of "intelligence" for which I would say that ant (and termite) colonies exhibit "collective intelligence":
My examples are primarily in the context of leaf cutter ants and/or termites that grow fungi :
In terms of being able to execute complex patterns of activity in order to achieve (apparently) purposeful goals. No single individual carries out all of the steps from gathering forage, through chewing it up, through growing the fungus that ultimately the colony survives on. Thus, as a whole, the colony grows the fungus that they live on, while no individual is capable of doing the whole jobs.
There is a pattern of pheromones that exists around/among the individuals that guides the manner in which they conduct their activities. This pattern of pheromones encodes information about the state of the colony and its environment in a manner completely analogous to the way in which the pattern of neuronal connections and activity encodes information in more obviously intelligent agents, like humans.
The second point presupposes a bit of materialism with respect to intelligence, but I'd claim that being able to identify the physical embodiments associated with different forms of intelligence makes it more clear that "ant colony intelligence" is of a similar enough kind as "human intelligence", that for some discussions lumping them together is appropriate.
To me the key point is that you can take at least some features that we usually describe of as intelligent, see that they exist in an ant colony as a whole, yet do not apply to individuals within that colony.
Self Organization in Biological Systems has several chapters related to social insects.
I think it depends on what you mean by intelligent? In what way would an organic lifeform be considered intelligent? What are the criteria that you would posit in order to say, "aha, that is intelligent life"?
As in human intelligence, this question is already contentious. To consider this of animals, even more so.
One often used criteria for animals is whether it has some kind of self-consciousness, is able to give itself an identity, or whether it is able to solve analytical questions that may be manifested in various forms. For instance, whether the decision of a lion (or some other animal) to favor a relative over another is due to biological or social condition or due to cognitive processes. By this reasoning, individual ants would not be considered intelligent.
However, in groups, it may take on the form of intelligence. But this does not mean that individual ants are intelligent, only that they behave in what seems like intelligence to us. There is an important difference here. The system or movement/activity of ants may seem like it is behaving intelligently but what could actually be the case is its reaction to external processes, that are ecologically shaped. That would not be considered intelligent in our sense of the word.
