The Best Insecticide

Surprising invaders greeted us this morning.  From Photo 1 you can see what are known as warrior ants or soldier ants, and they streamed into our office. Their way of life is to move through the rainforest, in columns like the Roman armies. For that reason they are also called legionary ants. You can see them moving in Video 1. During their travels, they carry queens, eggs, larvae and also food. When they locate a new area they build a camp at the base of a tree or in a hole in the ground. Later hunting groups are organized and they go out to explore. They are one of the most feared predators of the tropical rainforest:  confronting them is crazy and can end very badly. All you really can do is just get out of their way.

Photo 1: Eciton Burchelli Group

Eciton Burchelli on the move

Video 1: Eciton Burchelli’s moving column

For us, as humans, they are very good visitors. They are great hunters and can eat almost everything, even small mammals like rats and other pesky animals. Rats can only flee from them, for while the warrior ants are tiny their coordinated columns will overpower the small mammal. People are often, but needlessly, afraid of these wonderful predators. People are so afraid of them that there is a 1954 film called The Naked Jungle (In Spanish: Cuando ruge la marabunta) in which these ants appear. It is a classic of the horror films of bugs and in the film we can see a young Charlton Heston fight against these indefatigable ants (Foto 2).

But for humans they are not dangerous.  A professor of mine at the University of Salamanca told me that in Brazil the indigenous people use them to eliminate the pests of certain crops. The indigenous supposedly manage the warrior ants with fire or using captured queens, but I have not been able to confirm that the story is true. I have also heard that once two drunken people died from being unconscious and eaten by these ants, but I have not been able to find a reliable reference to this either. I once had the opportunity to see one of these armies attacking a yellow hornet wasp. The hornet nest was bigger than my head and the wasps tried to defend it. The fight began with the fall of the sun and spread throughout the night and part of the morning but the wasps were ultimately unable to resist the attack. The nest was destroyed and all the wasps and all the ants that died during the battle were collected by the soldier ants.

Photo 2: Poster of the movie The Naked Jungle

In Costa Rica we have several species of these ants but the most common is Eciton Burchelli. Those who have visited us today seem to be of that genus, but we are not sure of the exact specie. They have left the building completely clean in a matter of a few hours. The animals that have not managed to flee have been hunted by the ants and transported to the jungle. They will be part of the colony dinner. We thank them for their work and they can come back whenever they want. But if you don’t want them to enter your house or room. You can do the following. When the first ants in a column enter the door you must kill three or four. The column will withdraw and regroup, they will try three or four attacks after that they will decide to go to another place to hunt.