UK scientists discover multiple antibiotics used by fungus-farming ants to protect colonies

Sunday, August 29, 2010

University of East Anglia researchers led by Dr Matt Hutchings have discovered that leafcutter ants deploy several antibiotics to protect fungi they grow as food for their queen and larvae. It is the first time ants have been found using more than one antibiotic in combination. The new antibiotics discovered have anti-fungal effect, and can be useful for modern medicine. UK Medical Research Council funded the investigation.

Leafcutter ant Acromyrmex octospinosus on a stick carrying a leaf
Image: Deadstar0.

Acromyrmex octospinosus leaf cutter ants form the biggest known animal colonies, reaching several million individuals. They are native to South and Central America, but are now found in the southern United States as well. They are known to grow fungi gardens, and this is why the researchers looked into the interaction of ants and fungi. The scientists collected them from three colonies in Trinidad and Tobago. UEA professor Dr Matt Hutchings explained, "This was really a fun project which started with a PhD student, Joerg Barke, streaking leaf-cutting ants onto agar plates to isolate antibiotic producing bacteria."

The health of a certain type of fungus gardens is vital for the ants colony since the fungus is used to feed larvae and the queen. The antibiotics act both as herbicides and regulators of fungus growth. The antibiotics are produced by actinomycete bacteria, which live in a state of symbiosis with the ants, and are found on the bodies of the ants themselves. The symbiotic relationships benefit both the ants and the bacteria.

As a result of the study, a new antibiotic has also been discovered. It's related to nystatin, one of the antifungals used in modern medicine. The researchers expect to discover more new antibiotics and are optimistic about their use in medicine. Dr Matt Hutchings who was leading the research said, "It's also very exciting that ants not only evolved agriculture before humans but also combination therapy with natural antibiotics. Humans are just starting to realize that this is one way to slow down the rise of drug resistant bacteria — the so called superbugs."


Joerg Barke, Ryan F Seipke, Sabine Gruschow, Darren Heavens, Nizar Drou, Mervyn J Bibb, Rebecca JM Goss, Douglas W Yu and Matthew I Hutchings (2010). "A mixed community of actinomycetes produce multiple antibiotics for the fungus farming ant Acromyrmex octospinosus". BMC Biology 107 (34). doi:10.1186/1741-7007-8-109.