'Here I call attention to evolutionary addiction, whereby a host trait evolves a need for microbes without having been improved by them. Evolutionary addiction should be considered when interpreting microbe-removal experiments, as it is a distinct and potentially common process. Further, it may have unique implications for the evolution and stability of host–microbe interactions.'

https://www.cell.com/trends/microbiology/fulltext/S0966-842X(23)00224-X