Eco-evolutionary significance of 'loners'
Tarnita, Corina et al. (2020), Eco-evolutionary significance of 'loners', Dryad, Dataset, https://doi.org/10.5061/dryad.zs7h44j4k
Loners, individuals out-of-sync with a coordinated majority, occur frequently in nature. Are loners incidental byproducts of large-scale coordination attempts or are they part of a mosaic of life-history strategies? Here, we provide empirical evidence of naturally occurring heritable variation in loner behavior in the model social amoeba Dictyostelium discoideum. We propose that Dictyostelium loners—cells that do not join the multicellular life-stage—arise from a dynamic population-partitioning process, the result of each cell making a stochastic, signal-based decision. We find evidence that this imperfectly synchronized multicellular development is affected by both abiotic (environmental porosity) and biotic (signaling) factors. Finally, we predict theoretically that when a pair of strains differing in their partitioning behavior co-aggregate, cross-signaling impacts slime-mold diversity across spatio-temporal scales. Our findings suggest that loners could be critical to understanding collective and social behaviors, multicellular development, and ecological dynamics in D. discoideum. More broadly, across taxa, imperfect coordination of collective behaviors might be adaptive by enabling diversification of life-history strategies.
Excel file containg the data used to create figures: 1, 3, 4, S1,
Video S1: Strain NC85.2 is shown aggregating in a 2% agar substrate.
Video S2: Strain NC85.2 is shown aggregating in a 3% agar substrate.
Video S3: Strain NC28.1 is shown aggregating in a 2% agar substrate.
Video S4: Strain NC28.1 is shown aggregating in a 3% agar substrate.
Video S5: Closeup of Video S2 in a region that ended up with high loner density.
Video S6: Closeup of Video S2 in a region that ended up with low loner density.