Localized decision making in distributed biohybrid swarms. (a) Snapshots of the signal concentration field for two populations of NanoBEADS seeded at various ratios leading to steady state activation (green) of the larger and steady state inactivation (black) of the smaller (i), steady state activation of both (ii), and steady state inactivation of both (iii), average signal concentration perceived by the agents of the larger (b) and smaller populations (c) vs time for each ratio (legend indicates percentage of total dose), average intracellular GFP concentration for agents of the larger (d) and smaller (e) populations vs time for each ratio, (f) the activation time for each population of agents for each ratio, and (g) activation time for each population of BacteriaBots seeded in an analogous scenario across five simulation replicates. The overall concentration of NanoBEADS and BacteriaBots contained an equivalent concentration of bacteria (4.8 × 109 ml−1; 1 per NanoBEADS or 12 per BacteriaBot) in all scenarios.