Evolution: Ant trail pheromones promote ant-aphid mutualisms.

Summary A new study shows that trail pheromones produced by an invasive ant species suppress the dispersal and stimulate the reproduction of cotton aphids that the ants can ‘milk’ for honeydew. Aphids use these pheromones as a signal of ant presence and respond adaptively, analogous to early stages of animal husbandry where animals were attracted to human settlements.