A surprising discovery has resulted from an unintended slingshot hit on a Cecropia tree in Panama: the Azteca alfari ants that dwell inside these trees are often willing to repair damage to their living habitats.
Alex Wcislo, a high school student from Panama, shot a hole through a Cecropia tree with a clay ball thrown from a slingshot while wandering in the forest. The ants residing inside the Cecropia had neatly sealed up the slingshot hole when he returned to the scene the next day.
Wcislo and five of his student friends continued their research by drilling holes in other trees to examine how they could be patched up.
Sure enough, the ant repairs occurred on numerous occasions. The experiments were then written up and published as part of the Smithsonian Tropical Research Institute (STRI) volunteer program in Panama.
Azteca ants and the trees that host them have a well-established symbiotic relationship: the ants will try their best to defend the trees against herbivores in exchange for nutritious oily secretions from the leaves to consume and shelter within hollow stems.
What's unique here is that the insects also repair damage to their tree buddies if their refuge is threatened. According to the new research, this appears to happen more frequently when a colony's brood (eggs, larvae, and pupae) is in danger.
Repairs are created utilizing material discovered within the plant stem itself, but this does not happen in every case - in fact, only 14 of the 22 drilled holes were repaired. Further research could be conducted to determine why this is the case.
"The reasoning behind hole repair behavior could be because a hole in the wall exposes the ants' vulnerable immature stages to external pathogens, predators, or changes in other environmental parameters," write the researchers in their published paper.
The team, however, can't totally rule out the possibility that the tree is gaining some advantage from this ant behavior, such as antibacterial secretions near its damage.
The holes created by the toenails of sloths and anteaters are often an issue for Cecropia trees, which may be why the ants they're sheltering have evolved to behave in this way.
For these young scientists, understanding what variables encourage ants to take action could be the focus of future research; however, this could be something they can tackle after graduating from high school.
The research has been published in the Journal of Hymenoptera Research.
