how have these ants evolved?
They forage for leaf sections, but then convert their primary food source to the fungus these leaf cuts grew.
Fungus-growing ants
Early ancestors of attine ants were probably insect predators. They likely began foraging for leaf sections, but then converted their primary food source to the fungus these leaf cuts grew. Higher attines, such as "Acromyrmex" and "Atta", are believed to have evolved in Central and North America about 20 million years ago (Mya), starting with "Trachymyrmex cornetzi." 
what is lycoperdon echinatum? A type of puffball mushroom. where is it found? Africa, Europe, Central America, and North America are there any species similar to it? L. echinatum you mentioned it was a type of mushroom, what was it again? Puffball mushroom is it edible? Young puffballs can be edible. are you able to classify this mushroom? Yes, the true truffles (Tuberales) are gasteroid Ascomycota. what is the last word you just mentioned? It is a phylum of the kingdom Fungi. are they beneficial to humans? Yes, ascus fungi have brought some important benefits to humanity. how do these mushrooms reproduce? It produces microscopic spores inside special, elongated cells or sacs. what kind of relation do they have with animals? The genus "Xylaria" colonize the nests of leafcutter ants and other fungus-growing ants. the last type of ants that you just mentioned, how do they mate? The winged males and queens then take their nuptial flights to mate high in the air. do these ants help in farming or gardening in any way? Yes, it helps in both. where are such ants normally found? UNANSWERABLE what is their habitat? Lower attines mostly live in inconspicuous nests with 100-1000 individuals and relatively small fungus gardens in them.
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Fungus-growing ants [SEP] Evolution
Early ancestors of attine ants were probably insect predators. They likely began foraging for leaf sections, but then converted their primary food source to the fungus these leaf cuts grew. Higher attines, such as "Acromyrmex" and "Atta", are believed to have evolved in Central and North America about 20 million years ago (Mya), starting with "Trachymyrmex cornetzi." While the fungal cultivars of the 'lower' attine ants can survive outside an ant colony, those of 'higher' attine ants are obligate mutualists, meaning they cannot exist without one another. Generalized fungus farming in ants appears to have evolved about 55-60 Mya, but early 25 Mya ants seemed to have domesticated a single fungal lineage with gongylidia to feed colonies.