Fig. 3: Aiming and cost saving allow 2TFT to beat random attackers.

a Diagram comparing likelihood of successful T6SS attack for random firing (top) and retaliatory firing (bottom). b Measurements of absolute and non-clonemate cell hit probabilities from static, mixed-cell populations, for random (R, blue) and retaliatory (2TFT, yellow) T6SS firing. Statistical test for absolute hit probability comparison: two-sample, two-sided t test, no adjustment for multiple comparisons, t = −125.0560, effect size (Cohen’s d) = 17.676539, p = 2.2803e − 190. For comparison of non-clonemate cell hit probabilities, we use the same test; here t = −160.6783, effect size 22.6885, p = 1.0388e − 211. In both cases, n = 100 firing events taken from same sample, giving 198 degrees of freedom. Whiskers, boxes, and centerlines denote ranges, interquartile ranges, and median values, respectively. c Visual comparison of R and 2TFT cell growth rates during competition. Cell configuration and magnified sections are colored by cell type (left) or by growth rate (right). Magenta arrow highlights a single TFT cell whose growth rate is reduced by active firing; dead cells are outlined in red in the right-hand panel. d Comparison of R and 2TFT cell population average growth rates, measured at the end of five separate R vs. 2TFT competitions (statistical test as in b; t = −207.4396, effect size 131.3978, p = 3.2643e − 16, growth rate from ~10,000 cells across five independent simulations, 8 degrees of freedom). Circle markers indicate population means. e Comparison of R vs. 2TFT competition outcomes, in which 2TFT strategists are modified to remove T6SS aiming (bottom row) and/or cost saving (right column), for increasing weapon costs c (see legend, top left). Circles and lines correspond to data points and their means, respectively. In b, d, ***p < 0.001. Source data are provided as a Source Data file.