Beware of questions of the form of: "What is the purpose of..." Such a question is meaningless in most cases, and from different points of view one gets different answers.
Are you asking the question as, for example, a philosopher, a biologist, a farmer, a human, an ant eater, or a fire ant? For the philosopher, if there is an answer, it might be something like: "It depends on what you mean by having a purpose, which is not in general obvious. There might be many purposes for many things to many interests, or there might be none at all. If there must be some purpose, it is not clear that we can know the purpose for everything; the purpose of a hammer in a hardware store might be to make a profit. In a carpentry workshop it might be to drive a nail. In the hands of a burglar it might be to break a window. On a scale it might be to balance a weight; in a doorway it might be to prop the door open. To an experimenter the purpose of a fire ant might be to find out whether other fire ants are likely to bite, or sting, or both."
The biologist might say: "The purpose of the fire ant, if you insist on having a purpose, which is a very artificial and strained kind of idea, is to make lots more fire ants like itself."
The farmer might say: "To kill pests that eat my crops, or, evilly, to prevent my cattle from grazing in my pastures."
The ant eater might say: "Yum yum."
The human might say: "To obey my commands, because I have dominion over them. I have a little book that tells me that."
The fire ant might say: "To provide food and shelter for myself and my nest mates, and to kill and eat anything that interferes with that."
Until you can make sense of such ideas, and work out what the idea of purpose means for such points of view, there is no way to answer the question.
And while we are thinking of treacherous kinds of ideas, another kind of question to beware of is: "Why..."
Such questions can mean too many things or too few to answer.
Why are such questions dangerous? What is their purpose?
What is the purpose of people, or frogs or hermit crabs? The only purpose which any biological species has is to breed and create offspring to perpetuate that species.
Their purpose is to survive, which in the case of ants, is accomplished by a highly cooperative community working together.
Yes - they are basically an egg-laying machine. Their sole purpose is to increase the size of the colony, by laying eggs that will develop into new adult ants. These will replace ants that have been killed by disease or other animals.
Entymologists have discovered that ants (and other insects) exude pheromones (smell hormones, simply put), which are perceived as instructions by other ants, depending upon the characteristics of the pheromone exuded.
Ants milk aphids. Otherwise, another good name for them is just "plant lice."
There is a "queen ant", which is a breeding female. There is no "king" ant, male ants are called "drones". The non-breeding (sterile or sub-fertile) female ants are called "workers". Depending on the species, there can be anywhere from one to ten queen ants in a colony. They are raised from larvae specifically for the purpose of breeding.
Yes ants do produce ants to continue the family.
red ants
Elmo's Ants.
The main job of a queen bee or termite is to lay eggs to supply new members of the colony.
These are all types of ants
Ants that eat other ants.
Not all flying ants are carpenter ants. However, all carpenter ants can fly. There are various types of flying ants. Carpenter ants can be distinguished by their larger size and reddish tone to their body.
Like all living things, ants primarily serve their own purpose, especially Prime Directive #1: Survive, and Prime Directive #2:Reproduce. They are also decomposers, they farm fungi, and they aerate the soil.