A number of plant species have come to depend on ants to disperse their seeds. To entice the ants, the seeds have a tasty, lipid-rich structure called an elaiosome at one end, and the ants carry the seed along when then take the elaiosome back to their nest. Here, a Formica exsectoides mound ant has found the seeds of leafy spurge, an invasive pest plant whose spread might be facilitated by ants. Wisconsin, USA
Plants of the genus Inga have nectaries on the upper surface of their leaves to attract ants that may remove the plants' herbivores.This one has brought in a Camponotus carpenter ant. Napo, Ecuador
Pheidole minor workers gather nectar from an Inga leaf. The plant uses the nectary to attract ants that clean the plant of herbivores. Maquipucuna reserve, Pichincha, Ecuador
