Biological Warfare - Soil: Reflections on the Basis of our Existence - page 104

Antibiotic resistance is a serious and growing problem in the medical world and
we humans might do well take a leaf or two out of the ants' topic.
Ants can transport tonnes of leaves and are capable of causing significant dam-
age to tropical plantations. The most attractive leaves to the ants are thin and high in
sugar. When the scout ants locate a source, they emit an odorous substance and leave
a trail so worker ants can find the site. Ants structure their communities on clearly
defined roles. Like humans, they have colonised most environments and are particu-
larly successful in the Tropics. In some rainforests they account for a third of the ani-
mal biomass, despite representing only a few percent of the total number of species.
I share with leafcutter ants an interest in growing fungi, and for years have
dreamt of making a mushroom patch in my back garden. Mushroom growing is
the perfect complement to horticulture because the dark recesses of the garden
eschewed by plants make prime spots for fungi. Leftover mushrooms are also
Unconditional collaboration . Leafcutter ants carefully excise pieces of leaf of just the right size
for transport to their underground nest. There they chew the leaves into a mass on which a special
fungus grows and then live off the fungal mycelium. Both parties are completely dependent on
this coexistence, which has been ongoing for more than 50 million years. It is remarkable that
the ants have succeeded for so long without encountering the problems that have afflicted human
agriculture in its short history
The leafcutter ants tend their fungi carefully. They lick the hyphae clean and remove fungal
spores and other waste that can infect the colony. They also import bacteria that produce antibi-
otics which the ants then use to prevent undesirable bacterial growth. They place the fresh leaf
mass at the top of the culture, while the white fungal mycelium grows upwards. The ants harvest
the lower mycelium, which constitutes their only food