Biological Warfare - Soil: Reflections on the Basis of our Existence - page 103

Magic chemicals . Plants and fungi produce all sorts of substances to defend themselves against
external attack. Many have long been used in human medicine. At the Eden Project in Cornwall,
modern-day shamans from Peru have painted their most important medicinal plants on the wall
of an enormous greenhouse containing an entire rainforest. Tourists and school classes come
from near and far to visit the Eden Project and learn about the rainforest and the people who live
there. The plant in the picture is called chiric sanango in Spanish and grows in Amazonia
We Have Much to Learn from Fungi-Friendly Ants
Humans are not alone in harnessing the benefits of antibiotics. In a rainforest in
Ecuador I watched a long line of leafcutter ants descending a tree trunk, clutching
large pieces of leaf in their jaws on their way to their underground nest. Leafcutter
ant nests can be several metres deep and cover tens of square metres. In the nest,
ants chew the leaf pieces brought in by the workers to form a paste that serves as
a substrate for a fungus that lives in symbiosis with the ants. The ants eat the tis-
sue of the fungus, which could not survive without the care lavished on it by the
ants. The ants tasked with this role are tiny and their job is to patrol the fungal col-
ony and lick dirt from the hyphae. On their underside the ants carry Streptomyces
bacteria which produce the antibiotic that the ants distribute in the fungal garden
to keep unwanted guests at bay. It is clearly a highly successful method, consid-
ering that the ants have been cultivating the same fungus for millions of years.
Over time, unwelcome microbes acquire immunity to the antibiotic, but new varie-
ties are constantly evolving and the ants seem permanently to be one step ahead.