Spooning for antlions

Today marks the last day we spend at Palo Verde National Park. Our time here has been riddled with peccaries, coatis, and mischievous capuchins. It also marks the end of our independent projects. In fact I just submitted mine less than three minutes ago. We’ve spent the last nine days on our projects. The first four were dedicated to data collection and the last five have been for our presentations and paper write-ups.

            Walking around the station the first couple of days at Palo Verde I noticed little dirt cones sprinkling the ground everywhere I looked outside. They look kind of like inverted ant hills if that makes any sense. Like most things here, I had no idea what they were, but I soon found out that they serve as a home to the formidable antlions. It would be impossible to describe what the antlions themselves actually look like but they are tiny insects that dig these pits in the dirt and sit, buried at the bottom, awaiting an unsuspecting ant to wonder through. When an ant makes this mistake, it is immediately grabbed by the antlion, injected with venom and consumed. When finished with their meal, the antlions simply flick the leftover exoskeleton from their death traps and reposition themselves, waiting to strike again.

            Needless to say, as soon as I heard this, I knew what I wanted to do my independent study on. Luckily Christian shared my enthusiasm for the vicious killers and we teamed up for the project. Unfortunately for us, many other people also find the antlions just as cool and have studied almost everything there is to study about them. That makes coming up with an original project exceedingly difficult. We had between 10 and 15 well planned out projects ready to go before we found out from our professor, Mau that they had already been done. Eventually we worked with him to come up with an interesting project that was feasible within the constraint of the four days we had for data collection.

            We decided to look at whether or not the antlions would make their pits bigger in diameter if they failed to catch an ant five times in a row. The idea was that if the antlion was unsuccessful five times in a row that it would respond by increasing the diameter of its pit in order to increase its chances of a successful capture. So, we began scooping up the little insects out of their pits with a spoon the next morning, and would do so for the three following mornings following.

            After each morning, we would take our freshly caught antlions up to a little shack where our experimental sand boxes were primed for action. We constructed three sand boxes from cardboard in the recycling room and filled them with sand that we sifted so that the antlions would have the right soil particle size for their death chambers. Then, we planted them in five rows of five and let them build their pits for a few hours.

            The next part was the fun part, or so we thought. We gathered enough termites and ants for the experiment and headed up to the shack excited to test out the system. Unfortunately, only about half of the antlions re-built their pits in the sandboxes. We didn’t let this get us down however, and forged on with the experiment. The next three days were spent repeating this process, and I think we ended up spending upwards of 20 hours in that little shack. I was pretty sick of the whole deal by the end of it to be honest.

            I was feeling defeated by the time we sat down with Mau to do the data analysis. We had just spent four days working hard out under the sun in the morning and staring at sand boxes for the rest of the day and I hadn’t seen much change in the pit diameters, leading me to believe that we would have to reject our hypothesis. Despite my pessimism, the stats prevailed and we found that the antlions do indeed increase the size of their pits when they are unsuccessful at catching ants.

            I didn’t realize prior to this how satisfying it is to fully develop a study from beginning to end. Even though it was just a four day project and it’s not necessarily and earth shattering discovery, it’s definitely a very cool feeling to be responsible for answering a question about the natural world. I was also pleased to discover how much fun it was to go through the statistics and actually understand them. It’s a lot easier to care about every number when they all represent three minutes glaring at a spoon, on your knees in the dirt. 

Peter Saunders

Providence College