Figure legends
Fig. 1. Design of range expansion evolutionary experiment and long-term time series of dispersal in the experimental treatments. (A) Starting from a mix of 20 Paramecium caudatum founder strains, experimental population were allowed to disperse in 2-patch dispersal systems. For the range front treatment (red), only the dispersers were maintained and propagated for 1 week, until the next dispersal episode. In the core treatment (blue), only the non-dispersing residents were maintained at each cycle. In the control treatment, both residents and dispersers were maintained. (B) Observed levels of dispersal over the whole duration of the experiment (161 cycles, ca. 3 years). Lines show the trajectories for the individual lines (n = 15), the circles indicate the mean dispersal per treatment and cycle.
Fig. 2 . Model endpoint predictions for (A) dispersal, (B) growth rate (r0), and (C) equilibrium density (N ̵̅). In each panel, left: model predictions for the 3 treatments; right: posteriors distributions of the most likely winner strains in the range core (AMF_11_11A) and range front (goe_14) treatment. Circles are the average values measured for each experimental lines after 15-25 cycles (“short term”). Different colours represent the different treatments. The black circles represent the ancestral means (founder population).
Fig. 3. Winning probability (frequency of going to fixation in 10k model runs) of each of 20 strains from the founder population, as a function of its dispersal, growth rate (r0) and equilibrium density (N ̅), shown for range front (A-C), range core (D-F) and control (G-I) treatments. Full circles denote the potentially fixed and open circles the eliminated strains, according to genetic analysis (COI genotype). Regression lines obtained from multiple regression models. Different colours represent the different treatments.
Fig. 4. Short- and long-term traits associations observed in the experiment, in relation to short-term predictions in the model. (A-C) Bivariate correlations between dispersal, growth rate (r0) and equilibrium density (\(\overset{\overline{}}{N}\)). Circles are the average values measured for each experimental line in year 1 (cycles 15-25; “short term”). Stars refer to year 2 (cycles 74-84) and cross symbols to year 3 (cycles 154-161). From the distributions of the model predictions (outer part of graphs), the central range of each trait (50% high density probability interval, HDPI; thin lines) can be defined; the overlap zones of the HDPI (shaded square areas) represent the predicted trait association for each treatment, after short-term evolution. Observations falling outside of the overlap areas indicate deviation from the model, possibly due to de novo evolution (year 2 and 3). The black circles represent the mean ancestral trait association (founder population). (D) Principal Component Analysis (PCA) of all three traits combined according to the first two principal components of the PCA. The arrow length represents the loading value of the trait, while opposite arrow direction indicates opposite trend between traits. Different symbols correspond to the different years (circles, year 1; stars, year 2; cross, year 3). The ellipses are the 95 % containment probability region per treatments and year. Different colours represent the different treatments.