“If I were Ant-Woman, I don’t think I’d fight crime. I think I’d totally be going down there to see what they were doing.”
Erica Parra, an undergraduate researcher from California State University, is smiling as she pages through photos of ants on her computer. Yesterday, she spent part of the afternoon, along with her labmates, screaming at a televised soccer game in the corner of the dining room, but today she’s sitting at a lab bench, a battered field notebook on the table nearby. With long wavy black hair, a nose ring, and a colorful tattoo on her upper arm, Erica is a former art-student-turned ecologist who is determined to figure out how ant life varies under a messy cover of leaves and sticks on the tropical forest floor.
Erica is a first-generation college student from Los Angeles, the daughter of Mexican immigrants who she said would have preferred she work a little closer to home. But since an ecology class inspired her to change her major three years ago, Erica’s passion for ant biology has brought her all the way to Costa Rica, where she can explore the spectacular array of ant species that live in the tropics.
“I was so excited!” she says, reflecting on her first opportunity to try an independent research project at La Selva Biological Station three summers ago. She’s been coming back to the station every year since then, and for an ant enthusiast, it’s easy to see why. Here, where biodiversity seems to seep out of every available inch of ground, airspace, tree trunk, or puddle, the three-feet square plots where Erica does her experiments all have the potential to house not just one six-legged life form, but dozens. And they are certainly not all the same.
It turns out that the mess of cast-off leaves and sticks underneath the canopy—referred to as “leaf litter”—is actually quite variable. Leaf litter provides habitat for ant species, which are important for a number of ecological processes in the rainforest, but the depth and compaction of leaf litter changes as leaves decay or are disturbed by passing animals. Erica is curious to know whether the changing conditions in the leaf piles influence how many ant species are able to nest there.
Erica agrees to show me where she’s set up her plots, and so we don our backpacks and head out into the forest. On our way, she asks if I want to take a look out at the river, on the other side of the trail. While I’m pondering the misty fog rising up over the current and the wide, graceful tree limbs arching over the bank, my companion is instead crouching close the ground, delighted by the line of army ants just beside our muddy boots.
“I’m going to SnapChat these bitches,” she says, taking out her phone.
Erica’s plots are scattered close to the trail, and she lifts the protective screen off of the top of one so that I can see what’s going on beneath. An uneven layer of soggy leaves covers the ground, and on this plot she’s tacked down a thin layer of black mesh to further compress the leaf mélange. She’s attempting to mimic the process by which passing animals, such as peccaries, may trod on the fragile ant habitat, compacting and changing the depth of the layers below.
Erica thinks that where the leaf litter is deep, the temperature is more consistent, making the piles more hospitable places for ants to nest. To test the idea, she spends much of her time squatting next to a leaf pile, peeling back the sheets of debris in hopes of discovering ants wrapped cozily within the folds of a wet leaf or woody splinters of a small stick. As we’re examining the plot in front of us, she picks up a small twig and begins snapping it into one-inch pieces, showing it to me. She finds lots of tiny ant colonies living in sticks just like this one, but this time we’ve drawn a blank.
There are other ants around, though—Erica gleefully takes out a pair of tweezers and grabs a bullet ant off of a tree for closer inspection. Bullet ants are named for the painfulness of their stingers, and most researchers at La Selva take care to avoid provoking their retaliation. Recently, an artist visited the station looking for subjects to pose for photos while getting stung by one. Erica says she at first just wanted to watch, but then volunteered.
“It smells like garlic—can you smell that?” She smiles and gestures for me to come closer, but I hesitate a second. I’m clearly not as fearless as the woman holding the creature out to me, and as I watch the angry bullet ant thrash and squirm in protest, I’m not particularly eager to stick my nose right next to it. I ask her why she faced the stabbing pain of retribution from this one-inch little monster, just for a photograph.
She shrugs it off and laughs a little. “Just because.”