Desert Gardeners: Leafcutter Ants

You never know who you’ll encounter on a walk through the Sonoran Desert: javelinas and coyotes, Gambel’s quail skittering through the washes, cactus wrens perching quietly in cholla, Gila woodpeckers making a racket atop saguaros, Western pygmy blue butterflies flashing by so quickly you think your eyes are playing tricks on you.

But look more closely at the ground beneath your feet, and you might spot a tiny complex society. Builders and architects, gardeners and babysitters—desert leafcutter ant colonies are home to them all. As my husband, Will, and I walked the Terravita Nature Trail in Scottsdale last week, we were lucky to see them in action. On the surface, the construction crew moved one grain of sand at a time, while the foragers hurried past to shuttle leaves into the nest. Hidden from view were the underground farmers, who nourish a fungus that feeds the whole colony.

When I shared video clips of our sightings with Arizona State University postdoctoral researcher and ant expert Christina Kwapich, she confirmed my guess that the ants are of the Acromyrmex versicolor species. Though they’re often maligned for defoliating vegetation, they have positive effects on the life around them, increasing biodiversity, water infiltration rates and nutrient availability for plants. “Although leafcutting ant nests may become a nuisance in human-dominated systems,” wrote the authors of a study last year in the Journal of Integrated Pest Management, “in natural systems they increase landscape and plant diversity and can accelerate succession.”

As usual when I read such things, I wonder why it’s necessary to have so many human-dominated systems in the first place. It’s possible to create a world that isn’t so divided—to extend Woody Guthrie’s radical “This Land” perspective by making space for creatures who inhabited the prairies and deserts and forests from California to New York long before any of us humans did. Planting more plants that are helpful to wildlife—instead of needlessly covering millions of acres of land with lifeless lawns, gravel, asphalt and concrete—would be a nice start. I’m grateful to scientists like Kwapich, whose detailed photos, drawings and studies—addressing questions as varied as “Do harvester ants rescue nestmates from spider webs?” and “How do seasonal differences in diet influence worker development rate … ?”—demonstrate why we should protect even the smallest animals.

“It looks like they worked right through the holiday!” she wrote of our ants on the Terravita Trail, “though they are moving verrrry slowly due to the cooler weather we are having.” I can relate. Back home in freezing Sykesville, Maryland, I’m moving a bit slowly myself and, lacking a subterranean garden to retreat to, dreaming of the thaws of spring, when I can start ant-watching in my own garden again.

12 thoughts on “Desert Gardeners: Leafcutter Ants”

  1. I was in Tucson last week, and I think I saw what looked like small mounds like this. Are these ants in that area, too?

    1. Yes, I think they are! There is another species of leafcutter ant that’s not as common there, Atta mexicana; they’re occasionally seen in the extreme south, particularly at Organ Pipe, from what I’ve been told. So probably you saw these little guys that we saw in Scottsdale. 🙂

  2. I have always found ants to one of nature’s most interesting species. I could sit and watch them all day. It’s always puzzled me that so many just don’t talk the time to appreciate this tiny world of highly organized, dedicated and very busy individuals. Thanks for this insight into the benefits they provide. 😊🐜

    1. Hi Nicky! I so agree. They couldn’t be more hard-working and interesting — and really just content to do their own thing. People find them scary when they don’t look up close, I think — if they looked closer they might change their perspective!

  3. So peaceful to watch! It makes me sad to think most of us just trod upon small creatures. I will never forget witnessing a leaf cutter bee cut a small hole out of one of the leaves of my wild rose in my former garden and fly away. It felt like such a gift!

    1. Oh, thanks so much, Catherine. It is nice to hear from you, and I thought I responded a while back, but apparently not! You have motivated me to write more again soon. Hope you are doing well. 🙂

  4. Tiny animals have their mission on this planet, too. I wish I had wings on my feet so I could avoid stepping on them as I walk… Thank you Nancy as always!

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