We built an artificial nest to host a colony of Atta cephalotes at Adrian Pinto's lab at the University of Costa Rica, in San José. For this first trial, we built 3 garden chambers where the ants cultivate their fungus and one refuse chamber at the bottom, all connected with PVC tubes. The ants are fed local leaves and flowers in a diet designed by ant experts Allan Artavia and Rolando Moreira, who work in Adrian Pinto's lab. The nest was sealed to avoid air inside the colony mixing with air outside the artificial chamber. The feeding chamber, the vent, and some other nest areas were insulated to reduce heat loss. We installed 5 sets of sensors to monitor environmental nest conditions and to better understand how CO2 moves through the nests: CO2, temperature, relative humidity and barometric pressure. So far, the colony is growing and the fungus seems to have adapted to the lab conditions.
The Atta project was well-represented in the 2016 Summer REU (Research Experience for Undergraduates) Program held at La Selva Biological Station. Two students, Odemaris Carrasquillo (University of Puerto Rico) and Shaquetta Johnson (Jackson State University) worked with Atta co-PI Tom Harmon and his PhD student Angel S. Fernandez (University of California Merced). In consultation with Tom and Angel, the students brainstormed on research questions, developed a proposal and work plan, and then hit the forest for some exciting research. Together, Odemaris and Shaquetta worked to assess the carbon budget for several Atta nests, demonstrating outstanding teamwork. Odemaris (an engineering major) is focusing more on gas emissions (carbon dioxide) and Shaquetta (a biology major) on carbon inputs and Atta foraging behavior in terms of vegetation entering the nest.
The REU research has produced a ton of interesting data and some memorable times. For example, to study foraging behavior Shaquetta performed several exciting overnight sampling sessions in the rain forest (followed by many, many less exciting hours analyzing her foraging videos). For CO2 nest emissions, Odemaris has become an expert using our CO2bies (CO2 monitoring chambers), and has completed hundreds (literally!) of flux measurements on the nest soil and vents.
We are very proud of them and thank them for their tireless efforts working long days (and sometimes nights!) for 8 weeks under challenging conditions. We look forward to learning about their findings as they wrap up the REU experience in early August, and to seeing where their next steps take them.
Well done, Odemaris and Shaquetta! Thank you for joining the Atta Team and making a valuable contribution!
The lab is very quiet at 5am, even with the vacuum pump humming along, EggBert the trustie old centrifuge rocking and rolling with our soil samples, and crickets screaming outside the lab windows. Things get a little fuzzy as the 24th straight hour of work creeps up, but for some reason, I am very awake and moving faster than I was 8 hours ago. We are making a big push here at La Selva. The goal was to collect soils from Atta cephalotes leaf cutter ant nests and non-nest controls (across a soil depth profile) from each site and get everything from the same site processed and extracted for soil nutrients in the same day. That means each soil sample undergoes rigorous prodding, getting weighed out for soil extractions, a year long soil incubation, and for future DNA, enzyme, and PLFA analyses. And everything is done in triplicate to cover our bases as these tropical soils are notoriously variable. No two places on the forest floor are the same. Hence the 5am lab work. I am in no way alone here - Nicole Trahan and Diego Dierick, postdocs on the Atta project, are here in various states of exhausted. Amanda Swanson and Soren Weber are graduate students in Mike Allen's lab and they are here to help as well as learn biogeochemistry techniques. Its a full lab and everyone is working very hard. After a week of this grueling schedule with very little sleep, everyone is a little delirious. Soren has been singing non-stop for days. Nicole is laughing at her own jokes. Diego's hair is standing up straight (more than usual). Amanda remains calm and collected, an amazing feat considering the situation. I teeter between resolute single-mindedness to get things done and take on more work to lessen the load for everyone else and exhaustion as I also have the flu. In the end, everyone else takes on more work so I can get more sleep. But I think overall, its going well and in the end, we will have beautiful data. So its all worth in, in the name of science.