Many ant species form symbiotic relationships with plants. Symbiotic means that both the plant and the ant benefit from being together.
These plants make nectar for ants to eat, and grow hollow thorns for the insects to live in. This proves beneficial to the plant, because ants eat the plant’s fruit and spit the seeds somewhere else so they can grow. So, the plants grow and the cycle continues. But, scientists are not sure how or when this relationship between plants and ants first began.
The relationship between plants and ants goes all the way back to prehistoric times, when dinosaurs lived. That is why it is hard to tell if plants started using ants or if ants started using plants. All the evidence that scientists have is fossils, and those are few and hard to find.
Scientists were curious to know if plants first used ants to spread their seeds and serve as their bodyguard or if ants first used plants as a home and as food. Scientists use the word bodyguard because the ants believe a tree is theirs, so they attack anything that tries to get close.
To really find out, Matt Nelsen a researcher from the Field Museum led his coworkers in using existing data on ants and plants to determine the correct sequence. The scientists conducted a study to attempt to crack the age old chicken and egg situation. They determined that ants were relying on plants long before the plants evolved the hollow thorns. Therefore, ants started to rely on plants first.
[Sources: Phys.org; Field Museum; Discover Magazine]