Ever notice spotted ants and wonder if they’re diseased? Those spots aren’t symptoms of a disease. Certain ants actually farm gardens of a spongy fungus that they sustain themselves on. Those white spots on the ant are bacteria that help the ants to survive by killing off the ants’ enemy, a weed fungus that has the power to destroy an ant fungus garden in just several days, turning it into a brown oozy mess.
You might be wondering how bacteria protects these ants and their gardens. The key word is antibiotics. Many bacteria actually produce antibiotics that humans use to treat various infections. In fact, scientists have identified this particular bacteria as belonging to the genus, Streptomyces, which happens to be the same genus of bacteria which has been used to produce a large number of human antibiotics like streptomycin.
The antibiotic that this particular bacteria secretes targets the enemy weed fungus, leaving other fungi unharmed. In addition, it seems to scientists that only the female ants carry the bacteria on their bodies, probably because the females are the ones who tend the fungus gardens as well as the ones who go out and start new colonies, thus passing the bacteria on to the offspring colony.
What’s particularly interesting is the evidence that suggests that this relationship between the ants and the bacteria is highly evolved, suggesting these ants have been using antibiotics a lot longer than we have, perhaps millions of years longer.