Organized Forces Defoliating Amazon Rainforest: And They Ain't Human!

In every country in the Americas, except Canada and Chile, forces with tight organization and profound commitment to their mission are systematically defoliating the Amazon rain forest, as well as plants and trees in other ecosystems.

They're not human. Literally. They are ants: leafcutter ants.

"The Biogeography of Leaf-Cutter Ants (Atta cephalotes)"
by Airlangga Djajadi, student in Geography 316 (Fall 1999)
Department of Geography, San Francisco State University (Fall, 1999)

"Kingdom: Animalia
"Phylum: Arthropoda
"Class: Insecta
"Order: Hymenoptera
"Family: Formicidae
"Genus: Atta
"Species: Atta cephalotes

"Description of Species

"There are three castes of leaf cutter ants; workers, females, and males (Weber 1972). The workers are females and cannot reproduce eggs that become other workers but can make eggs that produce males (Weber 1972). The role of the female in a leaf cutter ant colony is very important, queens are essential and are part of the female caste structure. Males on the other hand do not work in or out of the colony and are winged to inseminate the virgin queens (Weber 1972)...."

There's quite a bit more: rather informative, if clearly written by a college student fulfilling the requirements of a class.

There's even a sort of rogue's gallery of these pitiless despoilers of the rain forest:


(Weber, via San Francisco State University Department of Geography, used w/o permission)

Leafcutter ants are remarkable creatures, and have a fan who has produced and maintains a more polished website:

"The Guide to Leafcutter or Leafcutting Ants"
A. San Juan

"Leafcutter ants (Atta, Acromyrmex) represent the pinnacle of social and technological expression in ants. Not only are they the only animals (other than humans) that cultivate their own food from fresh vegetation, but they also use sophisticated antibiotics against fungal pests in their gardens!..."

"...I've been studying leafcutters since 2001, and I invite you to contribute to our knowledge of these absolutely fascinating animals. So please join me and learn more by exploring the many notes, images, movies, and other information on leaf cutter ants in this site!..."

Never mind the impression of breathless enthusiasm given by those exclamation marks: A. San Juan seems to know his facts - and has put together a rather impressive website. His site has workable navigation, and is divided into sections: including an impressive array of photos from various sources, and - for those whose life would not be complete if they did not have their own leafcutter ant colony - a section entitled "Care and maintenance of Leafcutter ants."

Much, if not all, of the site is in English and en Español (sorry: there's quite a bit to this, and I didn't check every page).

For the rest of us, who may have an attitude toward leafcutter ants which is at best ambivalent, Orkin has a page on the critters:

"Harvester Ant"
Orkin

"The common species of harvester ants - the Red, Western, and California harvester ants each have unique behaviors, castes and tasks, feeding, nesting patterns and defense mechanisms. The harvester ant behavior differs between each species, seen through their feeding and nesting habits. In addition, unlike other ants that infest indoor structures, all species of harvest ants prefer not to invade houses and buildings, but will establish their nests around gardens or yards, often destroying vegetation.

"The red harvester ants can be aggressive. They give out a painful sting. Sometimes, the stings of red harvest ants can cause allergic reactions, especially to those sensitive to their venom. Aside from their powerful stings, the red harvester ant also bites viciously. However, due to the competition for food with the ferocious red fire ants, the population of red harvester ants appears to be declining...."

Wait a minute! This post started out with leafcutter ants, and now I spring "harvester ants" on you, the reader?!

Orkin explains:

"...Leafcutter ants also have been considered harvester ants. They exhibit high degrees of polymorphism with castes including the minims, mediae, minors and majors. They are divided based on their size to perform different tasks. For instance, the majors are considered the leafcutter ant soldiers, while the mediae are known as the foragers of food. The minims tend their fungus gardens, while the minors guard the nest from predators. Leafcutter ants, particularly the majors, are strong enough to cut through leather...."

You'll have to go back to the San Francisco U. paper for more detail on those "high degrees of polymorphism with castes including the minims, mediae, minors and majors." I did, but I'll freely admit that not everybody is quite as interested in polymorphic ants as I am.