Figure 1. Pa stably coexists with Aci2 when co‐cultured on alanine and glutamate despite being competitively excluded when co‐cultured on either resource alone.

1. Pa (Pseudomonas aurantiaca) and Aci2 (Acinetobacter sp.) were co‐cultured with a 10⁴ dilution every 24 h and 0.1% w/v alanine supplied as the only carbon source. Two biological replicates were performed for each of four initial Pa fractions: 0.1, 0.25, 0.75, and 0.9. Population sizes were measured via colony counting after the first, third, fifth, and seventh days (Materials and Methods). With only alanine supplied, Aci2 competitively excluded Pa.
2. An identical experiment was performed with 0.1% w/v glutamate supplied as the only carbon source. Aci2 again competitively excluded Pa.
3. A third experiment was performed with both 0.05% w/v alanine and 0.05% w/v glutamate supplied. Pa coexisted with Aci2 and reached a population fraction between 0.34 and 0.42 independent of initial starting fraction. Two‐resource coexistence was unexpected given the single‐resource competitive exclusions.