Students Accidentally Discover Incredible Ant-Plant Symbiosis, Thanks To A Slingshot Wound

An accidental slingshot wound to the trunk of a tree has led a group of high school students in Panama to discover an incredible ant behavior. They were able to understand how Azteca ants defend and repair their host plants.

Cecropia trees are "ant-plant" trees that have a mutualistic relationship with Azteca ants, the Smithsonian Tropical Research Institute (STRI) noted in a news release. In many ant-plant symbioses, the plants provide the ants with shelter, while the ants protect the plants against herbivores, said the authors of a study, published in the Journal of Hymenoptera Research.

At the beginning of the pandemic, a teenager in Panama accidentally shot exit and entry holes on a Cecropia tree trunk using a slingshot and clay ball. The next day, he discovered that the wound has been patched up by the ants living in the tree.

Five high school students then joined the STRI's volunteer program and conducted an experiment wherein they drilled holes into the trees and documented the ants' responses. They received help from STRI scientist William T. Wcislo and the experiments were conducted from June to November 2020.

The student team found that the ants began their repairs "immediately" using plant fibers and an "unidentified binding liquid," which is "probably" plant sap. The ants were able to reduce the size of the hole in just 2.5 hours and complete the repair work within 24 hours.

"Many organisms that build physical shelters for themselves or their offspring will regularly repair them when damaged, as do humans. But here we demonstrate that ants will work to repair a living structure, using plant material from inside the stem," the researchers wrote.

However, they also noticed that only about half of the colonies repaired the damage, while the other ants didn't or only did so "minimally." The researchers noted that this could be due to factors such as the size of the colony or the age of the plant.

The results of their experiment show a "new level of attention by the ants to their host plants," the researchers noted. Not only do they minimize the damage done to their host, but also "actively" work to fix the damage even if it may be for their own benefit, the experiment showed.

"Sometimes messing around with a slingshot has a good outcome," study lead author, Alex Wcislo, said in the STRI news release. "This project allowed us to experience first-hand all the intricacies behind a scientific study. All in all, it was a great learning experience, especially considering the difficulties associated with fulfilling this due to COVID-19."

The researchers thanked those who helped them to complete the study, which included Panama's Ministry of the Environment for giving them permits and even the police patrols who "tolerated" their activity during a time when there were "severe restrictions" on movement.