They've gone out to do different tasks, and the rate at which they meet as they come in and out of the nest entrance determines, or influences, each ant's decision about whether to go out, and which task to perform.
Han estado afuera haciendo diferentes tareas, y el ritmo al que se topan, a medida que salen y entran, determina o influencia, la decisión de cada hormiga de salir o no, y que tarea ejecutar.