The Art of Spelunking (Day 5)

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.

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View from inside Las Cuevas cave.
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Wrinkle-faced bat inside Las Cuevas cave.

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!”

An Ant’s Life (Day 4)

We began our first real experiments bright and early this morning on the cecropia, or trumpet tree, which is known for its mutualistic relationship with Azteca ants. The hollow tree tunk provides shelter for the ants, and, in exchange, the ants defend against herbivores vying for the cecropia’s lobe-shaped leaves. Though cecropia’s mutalism with ants is incredibly effective, young cecropia trees are not yet colonized. How, then, do these juvenile trees protect themselves from herbivory?

We hypothesized that young cecropia use chemical defenses (like toxins or pheromones) to deter herbivores. Our pilot experiment involved collecting generalist herbivores, such as grasshoppers, and offering them both adult and juvenile cecropia leaves. We may not have the technology for chemical analysis here, but we do have sophisticated pieces of equipment like Tupperware and a butterfly net. We’ll see tomorrow if the insects opt to consume one leaf over the other, or even die after ingesting a toxic leaf.

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A mature leaf-cutter ant nest.

The day’s ant theme continued with an afternoon dedicated to the fascinating life history of leaf-cutter ants. We looked at three leaf-cutter ant nests ranging from 1 to 10+ years old, observing their intricate tunnel systems and foraging trails. I was most amazed by the anthropomorphic qualities of leaf-cutter ants; they essentially act as farmers by cultivating fungus for food. The afternoon’s primary goal was uncovering these fungus gardens, which can sustain colonies of millions of ants.

Our focus today made reptile sightings difficult, as snakes and lizards are unlikely to be found in the vicinity of a large ant’s nest. Though we walked many of the same trails as yesterday, I wasn’t able to spot any of the Sumichrast’s skinks found yesterday in the leaf litter. I actually found better luck indoors today, spotting another common house gecko (Hemidactylus frenatus) running along the walls of our classroom.

Day 5: Look, a hole in the ground. Let’s go inside it.

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Today we hung vials of our urine on trees and went to the Las Cuevas Cave. It was so sublime. Get it? Sub-lime… stone. Sub limestone. Like going under the limestone, you know? Into a cave and stuff. Doing cave stuff like crawling through mud and bat poop.

I discovered an interesting biological phenomenon. There is a very blatant negative correlation between my fatigue level and my mental capacity. I sincerely apologise for the poor English and abysmal humour I’m subjecting you to. Although who am I kidding. Is anyone even reading this? Hi Scott and Adrienne, thanks for reading.

-Randy

Cave… More Like Rave

Today we went into Las Cuevas Cave, which is Spanish means “The Caves Cave.” Cool, but not exactly creative.

Here’s the whole TFB squad with our snazzy headlamps on. This is around when the electronic music began and we all started raving.

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This was the first totally dark cave system I have ever explored. The sights and sounds were foreign to say the least.

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The entrance to the cave was the only place all day where there was any penetration of natural light. Here cave swifts (birds) hunted for insects in what looked like the most fun method of hunting I have seen here in Belize. They flapped their wings vigorously for a few seconds and then dove down only to catch themselves midair when they ate a bug and repeat the cycle. Fun.

In the cave, life takes on strange forms. With little to no light the organisms here have evolved to survive without seeing much, instead feeling around with their long, slender limbs. For example, we have the cave cricket (pictured here) from the family Raphidophoridae is a bizarre take on the classic cricket. It has a humped back and long antenna for searching the cave in low light conditions. Creepy.

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What Goes In Must Come Out

Entrance to Las Cuevas
Entrance to Las Cuevas

I had so much fun today setting up pitfall traps and visiting the caves that give Las Cuevas its name.

In the morning we learned about nitrogen limitation in the canopy, and how most decaying matter falls to the forest floor. This lead us to hypothesize the animals in the canopy would be more attracted to a nitrogen source than animals on the forest floor. We used our own urine as the nitrogen bait for arthropods in the canopy and on the forest floor in our pitfall traps.

Later in the day we visited Las Cuevas (the actual caves), which was an amazing experience. I got to see some Mayan pottery, a peccary skeleton, and a long bone of a human skeleton.

Cave formations
Cave formations
Adrienne goes insane over pottery
Adrienne goes insane over pottery

In the caves I got covered in bat guano and actually saw the bats it came from. They may or may not have been vampire bats, but that was not confirmed. We definitely saw some species of leaf nose bat.


Arachnids were very exciting in the cave. I got to see the whip scorpion today, which is my new favorite species. I will have pictures to come of that. We saw the large darker colored whip scorpions and also the very light colored (white) tiny whip scorpions. I also got to see a cave spider.

Whip scorpion
Whip scorpion

After our hike Pedro (who works at the camp) found a very tiny tarantula on his shoulder. He says he thinks its a cave species because he’s never seen it before. I took detailed pictures of its eyes, back, and legs. Sophia and I are gonna call it the Little Boots Scorpion (Sophia claricus) if it is a new species.

Cave tarantula (new species?)
Cave tarantula (new species?)

We heard a fabulous talk by Boris Arevalo (the head biologist at FCD, which manages the Chiquibul). He talked about the limitations of conservation and the opportunities the Chiquibul presents.

Bold Choices With Ants

Wow are my feet sore from yesterday. These blisters aren’t helping either, but we had an incredibly fun day learning about ant symbioses.

First we tested hypotheses about how the young cecropera (trumpet) trees avoid herbivory before their symbiont azteca ants colonize them. Our hypotheses ranged from chemical defense to mimicry. My group tested mimicry, which is almost certainly not how they avoid herbivory due to their very similar leaf characteristics to the adult plant.

Later in the day we looked at the development of leaf cutter ant colonies, and the fungi they farm. We dug into a 1 year old nest, a 3-5 year old nest, and a 10+ year old nest, and looked at the difference in which castes are present in the nest and how big their tunnel systems are.

The 10+ year nest was huge and there were soldiers coming out of it in swarms trying to bite us. I was incredibly glad for the rubber boots at that moment, although I still got a bite from a soldier on my finger as I was taking an ant off of Scott.

I didn’t see very many arachnids today because we were mostly focusing on looking for ants and ant nests. I will look for some tomorrow at night when we can see their eyeshine.

Day 5: Staying hydrated

In the spirit of a true field course, today we set pit fall traps with our own urine. We are trying to test the differences in needs for nitrogen in Arthropods based on forest layers. We didn’t do too much hiking today, but I guess today was a bit more taxing on our mental strength than our physical.

Wrapping up our herbivory preference trials from yesterday, we found inconclusive results in terms of the presence of chemical defense in young Cecropia trees. This result was fairly expected based upon the small sample size, but in some cases I was a bit shocked. Six of the eight herbivores used(one caterpillar, one beetle, six orthoptera) did not consume any foliage. I had expected to see more bite marks on the leaves I suppose.

While we did not hike much today [so not many Lepidoptera sighting chances], I did still see Lepidoptera. When we went on the trail around the archeological sites at the research station to set our pit fall traps, I saw some butterfly. I mostly saw small brush-footed. I keep seeing one that’s about 6 cm in wingspan and it white with black markings and I am just not completely sure which it is. A classmate who is particularly skilled with the butterfly net managed to catch one of the fast flying teal and black swallowtails. I did not try with the net today but I managed to catch a moth in my room last night. It is  not listed in the additional field guide I have so I am not sure what it was. About 2 cm in wingspan, it was yellow and brown to the point it was almost colorful.

Tomorrow we will have to collect the traps, but we will also get to hear another guest lecture from one of the researchers at the station. We heard a presentation tonight focused on the area that we are staying in. I’m glad we are getting to learn more about the Chiquibul forest and I feel I’m starting to feel a bit more at ease with the constant animal and forest noises I don’t usually hear in the city.

Day 4: Staying Over at the Ant’s Place

Today was just another day in the field. We were investigating the interactions between two different species of ants with their respective environments, Cecroppia trees and the Azteca ants, and leaf cutter ants (Atta cephalotes). I didn’t really expect to see any roaches today, since the only roaches I knew that had some affiliation with ants are of the genus Attaphila, meaning ant loving. These guys are about 2-5 millimeters long and can often be seen hitching a ride on flying queen ants, which emerge right before the first rains in Belize. As we are coming in right at the end of the dry season, it may be possible to find these Attaphila, but I doubted whether we could spot a creature as small as a few millimeters in the midst of a giant ant nest.

One of our activities involved digging up leaf cutter ant nests to find their fungus chambers (see below!). During one of the digs, one of my colleagues spotted an inch long roach like creature in the midst of the angered ants. It appeared to have been actually living in the nest, a characteristic of Attaphila! Unfortunately we accidentally lost the roach as we were unable to stop digging, but after some in depth roach profiling with my colleague I learned that the creature was an inch long, lacking wings, shiny, and quite oval shaped (1 inch length, .5 inch width). This was clearly longer than any other Attaphila I had heard described in Belize or in other parts of the world. It may even be possible that this is a different ant loving (myrmecophile) species altogether. But without a picture I can’t verify, so hopefully I may be able to find another one during our activities!

A small sample of underground fungus farmed by leaf cutter ant (Atta cephalotes)
A small sample of underground fungus farmed by leaf cutter ant (Atta cephalotes)

(Nakian) May 21: Cave x Urine x Ruin

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.

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(Nakian) May20: Ants..so much ants

Today was a day ant. I was lucky enough to identify at least four species that I am familiar of. Our assignment to find the defense mechanism of juvenile cecropia tree naturally led me to find Azteca alfari which forms mutualistic symbiosis with the tree. Very fortunately, I was able to find a queen in the top compartment of a small branch. This confirmed that Azteca base center of the colony at the top of the tree. The queen was massive compared to the workers and I could even take pictures of larvae and recently developed nymphs.

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On the road we found army ants, Eciton burchelii. The swarm had few soldier castes which were at least 3 cm long counting its massive and sickle like mandibles. Hopefully I can find a bivouac of the army ants while I am here. On an acacia tree, I found Pseudomyrmex as expected but also on a different tree, Poniponera had formed a colony inside, which is unusual. Near by the open disturbed area where young cecropia were growing, I found Cephalotes ant with distinctive stout looking head and short abdomen. I was hoping to find one of those ants. Afternoon, I finally got to see the soldier caste of Atta cephalotes. They were indeed huge and the mandibles were sharp enough to pierce through my skin.

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As for the project regarding defense mechanism of juvenile cecropia, our group hypothesized that there would be a physical differences between the leaves of juvenile and mature (or already colonized) cecropia. The leaves of the juveniles were indeed smaller and could withhold more weight than the larger leaves of the mature individuals. this result connected to the further hypothesize that juvenile cecropia have tougher leaves that makes herbivory less cost efficient and thus predators will consume the juveniles in lesser frequency.

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Story of an A. cephalotes colony

The sky above the Belizean rainforest before the wet season becomes a royal ballroom of the Atta drones and to-be-queens. A queen successfully mated with multiple drones, filling her abdomen with sperms that will be used for next 20 years of her reign to produce millions of daughters. The queen dug down an open ground and horizontally to start her colony.
From the eggs, minor workers hatched and dug out from the first lair, shedding light for the first time in a while. Their first job is to bring in food for the fungi pallet that the queen brought as her dowry from the mother colony.
It has been 6 years since the queen first dug the colony. The fungi farm is successful and hatchery is busy producing major worker ants. But the colony as met challenges. Last summer some group of human came and ravaged her colony, exposing their pupae and larvae, and precious fungi to who knows what pathogens that will devastate their farm. The queen decided that their production yield, food surplus, and size were ripe to produce the soldiers.
Year 15, the colony has dominated the surrounding area. The soldiers effectively deter the predators and the workers bustle through the highway carrying food for their fungi plantation. The old empress has produced many queens that some of them already established daughter colonies in different regions of the forest. And yet again, the empire met with challenge of human intruders. Many precious soldiers were mailed and workers spent a whole day reconstructing the tunnels and rooms that were destroyed.
Year 21, the queen died. The workers lost their purpose once the last larvae hatched. Day after day old workers died but none hatched to replace them. The great Atta Empire fell as the last worker was eaten by a hungry bird.

Rice University