Leafcutter Ants- For Tomas

Several months ago, the world lost an incredible soul. My beloved uncle Tomas ended his painful, decades long battle with depression. He was one of the kindest, gentlest, most creative, and intelligent people I have ever known. The outpouring of grief and love from his family and community has been incredible and we all miss him terribly.

I was going to write this next blog post as though nothing had happened, as though my family hadn't been wracked with grief, as though the world would be the same without him. But I can't. My uncle had a wonderful passion and curiosity for the natural world which he shared with my cousins and me since we were very young. I remember a story of him tromping through the neighborhood on a search for monarch-sustaining milkweed with a pack of small children trailing behind, and that image remains with me. When I returned to school to study insects, he was one of my strongest supporters, always inquiring into what I was learning, sharing the knowledge he had gained, reading this blog regularly. Talking to him, he made me feel that my work was fascinating and important and propelled me to share more of the things I was learning.

His intellect and curiosity extended to all parts of the natural world: he loved birds, was passionate about the preservation of the Great Lakes, knew plants, and was interested in insects. He kept bees at his home in Wisconsin and was delighted by the leafcutter ants he discovered while traveling in Costa Rica. I always felt like the leafcutter ant was an appropriate animal for him- hardworking, an avid builder of beautiful things, grower of gardens, and committed above all to his family and community.

This is still a blog about insects, so in my uncle's honor, this will be a post about leafcutter ants. I only wish he could tune in to read it.


These are some of the videos he enthusiastically sent my after his visit to Costa Rica a few years back:

I love it. The wonderful green train of mismatched leaf pieces, wobbling comically in the jaws of the earnest ants carrying them. The tiny river that weaves nonstop down the trail.

The ants are like powerful and elegant tanks, carrying up to 5000 times their body weight in vegetation! Like humans, the ants build large and complicated societies with up to eight million individuals in a colony. The central part of their subterranean nests can reach more that 98 feet across, and are connected to small mounds extending out to a radius of up to 260 ft. Overall the colony can take up up to 6,460 sq. ft. of space!

You may think at first that these are herbivores taking their salad of leaves back to the nest to enjoy. But no, these are far more complicated creatures, in fact they are more often likened to farmers. Back in the nest, they grind up the leaves and use them to grow fungus, which then feeds the colony! Fungus is much higher in proteins and other important nutrients than plants, and the ants use this to their advantage.

A leafcutter ant fungus farm made in a lab (sse.royalsociety.org)

This is what the inside of a colony would look like if the rainforest floor suddenly became a series of plexiglass boxes.  A beautifully intricate structure that would be worthy of admiration on its own.

But wait, there's more. 

Ants applying pesticides. Yup, that's what I said.

See that white stuff on the heads and thoraxes of these ants? That is bacteria that grows on the ants that they spread to protect the fungus from harmful microbes and competing "bad" fungus. Essentially, the ants are using pesticides to protect their crops! Amazingly, ants have also "domesticated" their fungus crop so that it no longer produces reproductive spores, (spore producing structures (mushrooms) are not useful nutrition for the ants). Instead, new queens take a piece of the old nest to new nesting sites, allowing the fungus to spread to new areas. Over 30 million years, ants slowly domesticated fungus by adjusting the mixture of proteins and carbohydrates that they use as fertilizer; more protein causes the fungus to stop producing spore-producing mushrooms. The ants are instinctive propagators and biochemists! Mind boggled.  

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I am continuing this post after a long hiatus, during which there has been grieving, reflecting, and trying to make sense of things. Time has passed, but we still freely share memories and the accompanying tears and laughter. I remember my uncle's curiosity and wonder as demonstrated by his interest in these fascinating critters.

I'm not entirely sure how to close this post. I miss my uncle Tomas and I think about him often when I am exploring the natural world or building new things or spending time with my family. I miss his enthusiasm for the amazing things in the natural world, like those leafcutter ants in Costa Rica, and his respect and reverence for nature. I only hope that somehow, his spirit and energy continue to nurture the people and the nature that he loved.