Per usual, my day started at 5:00 am bird watching. It was a clear morning and the birds we saw were absolutely spectacular. The forest came to life as the Plumbious Kite took its regular perch and parrots flew overhead, two even landed in a tree right in front of us. The Melodious Blackbirds hopped onto the ground and the Social Flycatchers were chirping away. The highlight of morning was the sighting of two toucans. Their bright colors were absolutely stunning, with red and white tail feathers and a green eye ring. Another exciting event was the Plumbious Kite soaring down and catching an unfortunate moth.
After breakfast we devised an experiment utilizing pitfall traps, traps that an arthropod can fall into but not get out of. We’re comparing the nitrogen limitation, limitation of an environment to provide useable nitrogen to its organism, of the forest floor and the canopy as well as the arthropod species abundance and diversity. At each site we placed four vials, which were vials containing nitrogenous liquid in a tree and the floor and vials with just water in them. On the way we came across a shaft that led into a cave system right in the middle of the path! Looking down and imitating bat calls (kiss the top of your hand to create a high-pitched nose) we saw bats fly up almost out of the shaft. Since I’m the mammal taxon specialist, I tried to identify but to no avail. I couldn’t get a good picture and they wouldn’t let us me them long enough to identify them. They had light brown bodies and large dark brown wings and seeing them was absolutely amazing.
We returned to the station for lunch and then went to explore Las Cuevas Cave. The cave has a large entrance and is covered in bat guano. The ground is littered with Mayan Pottery, and there is a cenote (sinkhole exposing ground water). There, we had three presentation. The first was on Butterflies and Moths, the next was about Crickets, Katydids, and Grasshoppers, and lastly I gave my lecture on Cave Life. It was a very cool experience, especially to see a few things (like stalactites forming) that I had researched in real life.
After exploring the Mayan ruins above the cave and dinner, we ended the day with a night hike. We saw so many spiders and small critters that we hadn’t seen before and it was very eerie to hear all of the noises in the darkness.
I never truly appreciated the feeling of being clean until today. There’s one thing about coming back hot and sweaty after a hike, but it’s quite a different feeling returning from an afternoon of spelunking covered in a fine mixture of mud and bat guano.
But let’s backtrack. Today’s tasks began relatively lightly by wrapping up our (inconclusive) cecropia experiments. The day’s primary activity was the exploration of the cave from which Las Cuevas gets its name (and water). The 9-chambered cave is the center of an ancient Mayan ceremonial site, with each of the rooms representing one of the nine layers of the Mayan underworld. The cave holds numerous Mayan structures and pottery, and even what appeared to be a human femur. I doubt I’ll be picking up spelunking for recreation anytime soon, but our exploration gave me a newfound appreciation for cave biology. We found two species of bats within the cave system, as we crawled on hands and knees through narrow passageways that opened into large caverns. I thought I was clean until the cave’s final test: a tiny chamber with low oxygen content, housing a peccary skeleton. Let’s just say I was in great need of a hot bath after that adventure.
Finally, we set up an experiment to test nitrogen deficiency in arthropods of the rainforest canopy. Once again, we utilized extremely sophisticated technologies to create pitfall traps for arthropods in the canopy and forest floor, taking advantage of our most accessible nitrogen source: urine. I was thankfully spared from urine collection, but the afternoon was dedicated to setting up pitfall traps along the Maya trail (not named after yours truly). Though there were no sightings today, the leaf-litter our traps were set in are a prime habitat for venomous snakes; the forest floor was thoroughly checked for species like the yellow-jawed tommygoff (Bothrops asper) before setting traps. I did however spot several anole species along the Maya trail, all of which moved too quickly to be identified.
All in all, day 5 of EBIO 319 is best summed up by the following statement by Dr. Scott Solomon, “We’re exploring the mammalian excretory system!”
Today afternoon we travelled down to the nine stages of Mayan underworld. First the cave birds greeted us and ancient stairs made by the Mayans themselves led our way down. The muddy caught on our boots and the cave wall sparkled every time our headlight swept the embedded minerals. As the mud accumulated on our boots the great halls and tight entrances into another alternated. Bats glanced at our light from the holes dug over generations of their presence. We could see the cave entrance after overcoming the ninth chamber. On the journey back we entered a very tight opening where we ended up at where an unfortunate and lost peccary skeleton sneered at us. The poor animal must have been wandering in darkest dark until it died of starvation. The humidity generated from our own breath and apparently lowering oxygen level simulated the peccary’s death.
After returning from the underworld, we went to install our pitfall traps of our own urine. We set traps of urine set on the trunk of trees and on the ground, comparing the amount of bugs searching for sources of nitrogen. If the fraction of number of bugs in the urine trap over that in the control water trap in the canopy is higher than that of floor, it will count toward the hypothesis that nitrogen availability in the canopy is lower than that of forest floor.
In the process I caught some ant species. I am going to identify them tomorrow. One seemed like a species of Camponatus while the other was unsure. Judging by how I caught them so easily in the evening, these species seem active in that time. Also my ant catching skill seems to have improved.