Fungi interacting with Animals

One of the most ancient and complex mutualistic associations between fungi and animals is the farming of fungi by leafcutter ants.  

47 tropical species in two genera (Atta and Acromyrmex)

This relationship between ants and fungi has evolved over the last 50 million years. The ants and the fungi have become so dependent on each other that neither can live without the other. 
        

Leaf cutter ants cannot digest plant material and rely on fungi to digest it for them. The fungi benefit from nutrients in the leaves that the ants feed to them. 
    

These ants are members of 47 tropical species in two genera (Atta and Acromyrmex). Beneath its central mound, a leafcutter ant colony's underground nest can reach a size of more than thirty meters, and have smaller mounds radiating out to take up anywhere from 320 to 6,500 square feet of space. Such a colony can contain up to eight million individuals. Leaf-cutter ants seek out, cut, and collect leaves that they are unable to digest.

They build nests from the leaves and grow fungi on them. The ants actively cultivate their fungus, which varies according to the species of ant. They keep the fungus free of diseases and molds and feed it fresh leaf material. As the fungus grows, the tips of its hyphae swell up as they fill with proteins and carbohydrates synthesized from the nutrients in the plant leaves. 

The ants in turn feed on the rich hyphae tips. Thus, the ants receive nutrients from the plant leaves by way of the fungi. The fungi also break down toxic compounds in the leaves that would otherwise harm the ants.

The mutualistic relationship has even more complex adaptations. For example, a bacterium that lives on the ants secretes chemicals that act as antimicrobial agents (antibiotics). The ants also detect chemical signals from the fungus; if the fungus indicates that a particular type of leaf is toxic, the ants stop collecting it.

 underground nest can reach a size of more than thirty meters

Other types of insects also have mutualistic relationships with fungi. 

Ambrosia beetles live in the xylem of dead trees. They burrow tunnels into the xylem and inject fungi, which they cultivate. The fungi digest the xylem and the beetles and their larvae graze on the fungal mycelia. 

beetles and their larvae graze on the fungal mycelia. 

Wood wasps (Sirex sp.) inject their eggs along with spores of the wood-rotting fungus Amylostereum areolatum into pine tree xylem. They also inject a mucus that kills the tree. The fungi feed on the dead wood, and when the eggs hatch, the wasp larvae feed on the fungus. 
 

Female Sirex drilling into living Pinus radiata to insert eggs

        

Amylostereum areolatum

    

      
The wood wasp was introduced into the United States from Eurasia and is considered an invasive pest. 

Termites on the African savannah also cultivate fungi.