Earthy funk lures tiny creatures to eat and spread bacterial spores
The master chemists known as Streptomyces bacteria have turned a compound rich with the tangy odor of moist soil into a hitchhiking scam. This group of bacteria, the inspiration for streptomycin and other antibiotics, can release a strong, earthy whiff of what’s called geosmin. It’s not just an everyday scent for them. Some bacterial genes that regulate spore-making also can trigger geosmin production, an international research team reports April 6 in Nature Microbiology. When bacteria start making spores, geosmin wafts into the soil and attracts hungry little arthropods called springtails. They feast on the bacteria, inadvertently picking up spores that hitchhike to new territory, says Klas Flärdh, a microbiologist at Lund University in Sweden. Geosmin floats off many environmental microbes, including virtually all Streptomyces. People as well as many other animals can detect low concentrations of it. For instance, the common Drosophila lab fruit fly dedicates a circuit in its sensory wiring just to detecting geosmin, which the flies find repellant. That kind of disgust might...