Parasol ant, parasol ant, how does your garden grow?

A lone leaf-cutter ant. Photo via Thinkstock.
A lone leaf-cutter ant. Photo via Thinkstock.

A lone leaf-cutter ant. Photo via Thinkstock.

Yesterday I met biology professor and insect enthusiast Rebecca Rosengaus to discuss a new paper on the horizon about ant immunity. It was a great conversation and I’ve never been so enraptured by a conversation about bugs (although, I think bugs isn’t actually the correct term…)

In response to my questions about why anyone should care about ant immunity in the first place, Rosengaus said “because they’re awesome!” and then proceeded to give me several examples of why that is so. Number one example: The total biomass of ants makes up 15 to 20 percent of the total animal biomass on. the. planet.

This fact got the old wheels turning in my brain. If ants take up so much physical space, I considered, they must have a pretty big impact on the overall ecological system, right? Rosengaus agreed and told me a fantastic story of a particular type of ant in Panama, which, like all wood eating insects, serves an important ecological role of replenishing the nutrients of plant matter back into the earth.

In the case of the Panamanian parasol ants, as Rosengaus called them, millions of the tiny insects live together in a single nest performing agriculture, constantly tending to their “fungus-growing garden.”

Here’s how it works: Worker ants come out of the nest and go foraging for a good tree. They cut out little pieces of the leaves, then carry them back to their nest, suspended like a parasol over their heads (hence the name). Back at the nest, they pass the leaf off to the next ant, whose job is to chomp, mush, and crumble the leaf into a pulp. This pulp gets passed to the next ant in line, who lays it delicately on the garden.

And what does the fungus do? It feeds the ants!!! Brilliant little arthropods, right?!