The effect of bottleneck size on evolution in nested Darwinian populations

Previous work has shown how a minimal ecological structure consisting of patchily distributed resources and recurrent dispersal between patches can scaffold Darwinian properties onto collections of cells. When the timescale of dispersal is long compared with the time to consume resources, patch fitn...

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Bibliographic Details
Published in:	Journal of theoretical biology Vol. 561; p. 111414
Main Authors:	Nitschke, Matthew C., Black, Andrew J., Bourrat, Pierrick, Rainey, Paul B.
Format:	Journal Article
Language:	English
Published:	England Elsevier Ltd 21-03-2023
Subjects:	Biological Evolution Ecological scaffolding Evolutionary transition in individuality Major transition Population Dynamics Probability Stochastic model Stochastic model Evolutionary transition in individuality Major transition Ecological scaffolding
Online Access:	Get full text
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Summary:	Previous work has shown how a minimal ecological structure consisting of patchily distributed resources and recurrent dispersal between patches can scaffold Darwinian properties onto collections of cells. When the timescale of dispersal is long compared with the time to consume resources, patch fitness increases but comes at a cost to cell growth rates. This creates conditions that initiate evolutionary transitions in individuality. A key feature of the scaffold is a bottleneck created during dispersal, causing patches to be founded by single cells. The bottleneck decreases competition within patches and, hence, creates a strong hereditary link at the level of patches. Here, we construct a fully stochastic model to investigate the effect of bottleneck size on the evolutionary dynamics of both cells and collectives. We show that larger bottlenecks simply slow the dynamics, but, at some point, which depends on the parameters of the within-patch model, the direction of evolution towards the equilibrium reverses. Introduction of random fluctuations in bottleneck sizes with some positive probability of smaller sizes counteracts this, even when the probability of smaller bottlenecks is minimal. •Analysis of bottleneck size emphasising stochastic effects and few cells.•Direction of evolution at higher level depends on bottleneck size.•Significant evolutionary change can arise from occasional small bottleneck events.
Bibliography:	ObjectType-Article-1 SourceType-Scholarly Journals-1 ObjectType-Feature-2 content type line 23
ISSN:	0022-5193 1095-8541
DOI:	10.1016/j.jtbi.2023.111414