Scientific ANTics

It’s a pretty average night with a slight breeze blowing through the forest. I’m going about my work, just trying to bring my leaf back to the colony, when all of a sudden a giant beam of light appears and giant metal spears grab me and my friends and pull us into the air... After hours of sitting in a clear plastic cage, a giant appears, grabs my friends one by one and starts decapitating them… Excerpt from “Nightmare at La Selva: A Leaf-cutting Ant’s Tale.”

Now that isn’t a real book, but if it was would you buy it? This past week I’ve been working on my independent project, which involved killing many leaf-cutter ants in order to study them. As I went along I often thought about my project from the ant’s perspective and wondered how they would tell this story. The reason I thought like this was because during our stay at La Selva we heard a talk from the station director, Carlos de la Rosa, who challenged our class to think bigger than just the scientific community when publishing our results. While most people publish their work in scientific journals and then are done, we need to figure out how can we get our findings out there to the general community and how can we make them care. This is important because if the general population doesn’t care, conservation doesn’t work.

Now, I’m not going to be publishing a horror story on my independent project, so I guess my only chance to tell the story of my independent project in an approachable manner is through this blog. So, here is what you should know about my independent project.

Leaf-cutter ants are amazing creatures that help shape the forest. They cut leaves in order to grow a fungus, which they then feed to the queen and larvae. They need a lot of leaves to grow this fungus, and they can cut every single leaf off of one tree in a single day! Now the reason the forest isn’t completely bare, with leaf-cutter ants running wild is due, in part, to phorid flies. These flies help control ant populations by killing some of them. They hover over the ants, and once they have selected an ant with an ideal head size, they attack the ant and lay an egg in it’s head. Eventually this egg hatches, eats the ants head, and kills the ant in the process. While you and I might find this cool, ants don’t think this is cool, so big headed ants avoid dying by looking for leaves at night when the flies aren’t active.

But, scientists already know how all of this works, so my partner, Jocelyn, and I needed to come up with a new question regarding this relationship if we wanted to study the ants. *insert final jeopardy thinking music here* Finally, we decided on looking at how this relationship changes on the forest edge. Some of the reasons the forest edge is different from the interior forest is because there is a lot more wind and sun, which leads to less humidity, and also different plants grow there. It also means that phorid flies can’t live here. So, Jocelyn and I predicted that, during the day, ants would have larger heads on the edge of the forest and smaller heads on the interior; hence the “horror story” where we caught a bunch of ants and decapitated them. Once they were decapitated we were able to accurately measure the head size, and we found that *drumroll* we were wrong in our predictions! Ant head size isn’t significantly different between the interior and exterior. Now, even though this information does not support our prediction, it helps show that either it takes a longer time for ants to change their behavior to send out large headed ants during the day, or that the ants travel so far away from their colony into the forest to collect leaves, that they end up encountering flies anyways. And that is the gist of our project.

Now if you are thinking, “wow. I could totally do that.” You probably could collect ants, but do you have the patience and passion for this work? Over the course of 5 days working on this project, Jocelyn and I spent a combined 20 hours in the field finding 14 colonies and collecting 1140 ants, 85 hours in the lab measuring the head size and tibia length, and many uncounted hours coming up with this question, doing the analysis, and doing the write-up. Aren't science conclusions interesting once they explained in an easy to understand manner? But man, collecting data is tedious. Before I wrap this blog post up, here is one final fun thing we learned during this project: when you use the wrong magnification during ant measurements (and thus the data are not accurate), you have to disregard over half of the data in your project, and stay up extra late to make up for it, making your project that much more tedious. Yay science!

Rachael Lewandowski-Sarette

Northwestern University