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.
別の仕事をしに出て行きました　アリが出入りするときに 別のアリと会う割合が 外に出るかどうかや どの仕事をするかという判断に影響を与えます