This post is quite appropriate with us seeing the latest Ant Man movie last weekend. On a walk last week, my father-in-law pointed out the Palo de Diablo, or “devil tree”. Triplaris americana is found throughout the neotropics, from Panama to Brazil. It is a well known tree because of the poisonous ants that live inside it. Psuedomyrmex ants and the Triplaris tree form a symbiotic relationship. The ants protect the tree from insects and herbivores who want to eat the leaves and they also prevent seedlings and lianas from growing under or on the tree. When the ants die, the tree also gets a nitrogen from the decomposing bodies. In return, the ants get refuge inside of the tree and they also feed on sugars produced by the tree. Trees that benefit from ants living inside them are called myrmecophytes. There are many different types of trees that do this. I am most familiar with the Acacias of Costa Rica that were well studied by the famous neotropic biologist and one of my heroes, Daniel Janzen.
In the photo above, you can see the red-orange ants scurrying over the surface of the tree. We strongly tapped the tree several times before they came out. You can see in the photo below, my sister-in-law hitting the tree with the stick. The tree goes by many names, it was identified as a Palo Santo (Holy Tree) at an ecological park we visited yesterday. My favorite is the “Novice Tree” which it is referred to in Brazil. It is called novice, because only a rookie or someone new to the forest would disturb it. The sting from the ants delivers lots of pain which lasts up to 8 hours. I read of the poor tourist who was docking a boat in the amazon and grabbed the nearest tree on the banks to tie the boat and received multiple bites. There is no medicinal relief to the pain.
The tree unfortunately prefers disturbed habitats, which means the sides of roads (above) and other inhabited areas frequented by unlucky people. Triplaris species are members of the knotwood family (Polygonaceae) which is known for its swollen nodes present in some species. The tree has extremely large leaves and bright, pink, showy flowers and is often planted as an ornamental in gardens.
The leaves and buds of the Novice Tree (above). I read one story (unconfirmed) that villagers lynched a suspected motorcycle thief by tying him to a Triplaris americana. I read another story that the a compound in the toxin produced by the ants may have beneficial effects on arthritis.
A fascinating relationship and an example of the complex ecology of the neotropics. Speaking of ants, I have been seeing trails of the famous leaf cutter ants while walking out in the countryside. It is amazing how large the piece of leaf is compared to the size of the ant. They are so strong for their size! Taking the kids of the movie gave them a better appreciation of the ants they encounter here in Bolivia.