Year: 2026
Type: preprint
Abstract: ABSTRACT A major transition in the evolution of eukaryotic cells was phagocytosis: the ability of one cell to engulf another. In some cases, the engulfed cell persists, forming an endosymbiosis which is often mutually beneficial. However, it is unclear whether the interaction between the ancestors was also cooperative. There are clear benefits to developing the ability to eat a competitor, but can it ever be beneficial to eat a cooperator? We use a dynamical systems framework to identify the ecological conditions under which phagocytosis can evolve from a system of cooperating microbes. Beginning with a system of two cooperating species, we use invasion analysis to identify the parameter regimes under which a phagocytosing mutant can invade and the subsequent population dynamics. We identify a critical threshold that determines whether an invading predator will coexist with the cooperative community or replace members. Repeatedly invading with different predators, we find that the system saturates when there are three coexisting species, though this community does not have a single optimal composition. However, if we incorporate additional costs, we find there is a single evolutionarily stable community of two cooperators and a pure predator. Ultimately, we show that it is possible for phagocytosis to evolve from a cooperative community and, moreover, coexist with the original cooperating species. Highlights Predation can evolve from a cooperative ecology, as long as the prey species is sufficiently abundant. A predatory species can coexist with its ancestral cooperative community. There is a niche separation with one species displaying more predatory and the other more cooperative behaviour. Imposing a cost to mixed strategies leads to a unique ecologically and evolutionarily stable community consisting of specialist species (the original two cooperators and a pure predator).
Institutions: Umeå University, Santa Fe Institute, Arizona State University
Language: English
Subfield: Genetics
Domain: Life Sciences
Open Access status: green
Funders: Santa Fe Institute, Vetenskapsrådet
OpenAlex ID: W7221320717