Selection coefficients were determined for two-way competition experiments between <i>E</i>. <i>coli</i> (ancestral and evolved), <i>S</i>.

<p>Typhimurium (ancestral and evolved), and colicin-producing <i>E</i>. <i>coli</i>. Student’s <i>t</i> test was used to determine statistically significant differences between the ancestral and evolved communities, with correction for multiple tests done using Bonferroni’s correction method.</p> <p>(DOCX)</p>