Microbes vary their utility within a microbial community to optimize the performance of their effort, in accordance with a new study led by UCL and the University of Bath. Researchers made the breakthrough while probing one of the central questions in biology, namely, why individuals have progressed to collaborate rather than merely exploit the contributions of their competitors?
The report, released recently in PNAS, concluded that when microbes belong to groups consisting largely of their relatives, they greatly assist them in their cooperation, which is beneficial to the group. In contrast, when they are in a group of unrelated members, they will exploit the other members’ contributions.
The research crew investigated the social behavior of amoeba Dictyostelium discoideum or mud mold. These amoebas live on the soil as single-celled micro-organisms, but they come together to produce a slug-like creature once they are left with no food.
The new-formed slug-like unit can later develop into a productive organ made of a shaft and many spores. This is a process that calls for cooperation between the separate amoebas to develop into a productive and highly motivated unit.
Scientists noted that unrelated microbes within microbial community develop a shallow slug-like unit which crumbles eventually
Typically, biologists who attempted to answer this question tagged each individual as a collaborator or as a cheater. Nevertheless, this research demonstrates that even the simplest microbes comply to the economic fundamentals of collective investment, their contribution depending on the degree to which they participate in the success of the productive before-mentioned body.
“Many attempts to solve this problem are based on the assumption that individuals either cheat or cooperate. In these cases, cheating is often the best strategy and cooperation collapses, an idea demonstrated by games like the prisoner’s dilemma,” said Chris Thompson, a professor at the UCL and the author of the study.
The research team concluded that an equivalent combination of two phenotypes, in a microbial community where microbes are not related, did not lead any of the studied groups to sufficiently invest, resulting in a slug-like unit that didn’t turn into a productive organ, and which, eventually, crumbled.