How plants evolved to make ants their servants. Plants have evolved ways to make ants defend them from attacks and spread their seeds, and this new study shows how it happened. In a new study breaking down the genetic history of 1,700 species of ants and 10,000 plant genera, researchers found that the long history of ant and plant co-evolution started with ants foraging on plants and plants responding by evolving ant-friendly traits. Source 4y.