Monday, October 27, 2008

Some stolen photos... :)

So. On the issue of pictures... starting with a little history. My camera, which I purchased new in March, took quite a beating in August in London due to an unfortunate incident involving me foolishly swinging it in circles by its strap on a concrete walkway in Kensington Park. This resulted in me having to partially disassemble the camera in order to make it work again, as it somehow managed to land on and smash the shutter button. This worked temporarily, but I eventually had to repeat the camera surgery, this time removing part of the top of the camera. Now everything was fine. However, while we were in La Selva working on independent projects, my camera inexplicably stopped working. Any time a memory card was inside the camera, it would say "the memory card is locked," even though the memory card was not locked. Long story short, I ended up buying a new point-and-shoot after a three-week-long attempt-to-fix-camera saga in San Jose. SO. To make myself feel better about a month of no pictures, I stole some pictures from my friend Becca, who has an amazing camera and photography skills to boot. Here comes a small sampling of those from Las Cruces, Cuerici, and La Selva.

^Las Cruces: A soccer game that turned into an all-out mud brawl - I'm fourth from the left, I think. I believe this was the first time in my life that I literally (and not on purpose) ate a handful of mud... I was convinced that I would contract some terrible illness afterwards, but luckily this did not occur.

^Cuerici: Action shot of me during a really fun and highly entertaining all-day hike.

^Cuerici: Hanging out after deciding to walk the 3-ish kilometers back to the station instead of riding in the car... this after the all-day hike. Notice we're right at the level of the clouds.

^Cuerici: Out in the field studying forest fragmentation.

^La Selva: Billy's encounter with a howler monkey... how awesome. Sadly, I wasn't present.

^La Selva: Porcupine on the bridge cable.

^La Selva: Slug-eating snake we found on a night hike :)

^La Selva: During a free day, a few of us decided to go out and explore the forest. While following a trail that led off one of the main trails, we first found a strange house-like building that was literally covered in bats. Afterwards, we continued following the small trail down to the river, where we found this awesome cable-car contraption and propelled ourselves across the river to continue our hike. I probably shouldn't mention that this was during a thunderstorm...

^La Selva

^La Selva: butterfly... note Becca's awesome photography skills.

^La Selva: White tent bats. They make tents out of Heliconiaceae or Marantaceae leaves and cuddle up under them. Adorable.

Sunday, October 26, 2008

The Frog and Ant Project/Saga/Disaster

One important component of the OTS USAP (Undergraduate Semester Abroad Program) is independent projects (IPs). Essentially, students have a full week to plan, carry out, present, and write up an entire research project. There are two IPs throughout the semester, and the first one took place during our second week at La Selva. The reasons I'm making an entire post about my IP are a) it had a pretty interesting topic and b) it was somewhat hilariously filled with complications and problems. Here goes.

Project Development
My partner for the first IP was a student from University of Washington (Seattle) named Andrés, and after lots of paper-reading and researching, we decided that we wanted to do a project on poison-dart frogs (Dendrobates pumilio). This particular species is very common at La Selva. Adults are small - about 2.5 cm in length or so - and are aposematically colored bright red and blue. Their skin is only slightly toxic (i.e., not dangerous to humans), but this toxicity renders them generally unpalatable to predators. It has been shown that the frogs sequester their skin toxins from their prey, but no research has been performed to examine how this affects their foraging decisions. One important class of skin toxins are the pumiliotoxins, which out of hundreds of ant genera examined, have only been found in the ant genera Brachymyrmex and Paratrechina. Thus, the question we asked was this:

The Plan
Our plan was simple. Trap a frog and put four pumiliotoxin-containing ants and four non pumiliotoxin-containing ants in a container with it, and return later to see which kind of ant the frog prefers to eat. We had five days to perform the experiment and one to put together a presentation... and thus the saga began.

^Me with poison-dart frog.

Day 1
Morning #1 of our IP, and I was already panicking. By then, we should have ideally located both genera of ants somewhere at La Selva, but we had found neither. Andrés and I had spent hours in front of microscopes with giant ant books trying to identify ants we'd collected around the station and in the forest, but that proved absolutely impossible. We trapped ants around the dining hall, in the lab, in the field, and in the forest, and although we obtained lots of ant samples, we couldn't definitively identify a single ant. We also tried and failed to fashion some kind of enclosure for the ants and frogs, but either the ants or frogs (or both) managed to escape from every kind of enclosure we tried. At the end of the day, essentially nothing had been accomplished besides a lot of learning what didn't work.

^Ant identification = impossible.

Day 2
I was now panicking completely, despite Andrés's efforts to convince me that it would eventually work out. On day 2, though, we got a good break. Ronald Vargas, the station's resident ant expert, returned in the morning and came to our lab to help us identify our ants. At this point we got a small miracle: our lab was literally infested with Paratrechina ants, and another ant species we trapped near the dining hall (genus Pheidole) would serve as a suitable control ant. Our first method for trapping the ants in the lab was an aspirator, but much to Andrés's dismay, the ants were sucked right through the mesh and into his mouth when he tried to use it. Soon, though, we realized that we could somewhat effectively sweep the ants from the counter if we first baited them with honey. We decided to just use plastic bags tied closed with a knot for our enclosures, and after an intense frog-catching session, we set up 30 frogs in bags with 8 ants each during the afternoon. We returned after dinner to count ants, but none had been eaten.

^The Paratrechina ants infesting our lab.

Day 3
First thing in morning, we counted the ants again. Still, not a single ant was missing, although some had drowned in the moisture in the bags. We still hadn't found Brachymyrmex ants, so we set traps throughout the forest on epiphytes and in leaf litter, where these ants are (in theory) common. We then attempted to address the problem of our frogs refusing to eat. The first step was to eliminate the plastic bags. We managed to track down a graduate student at the station who had an excess of plastic containers with lids, so we borrowed about 60 of them. The containers had small holes poked in the lids, so we put a bunch of ants in a container with a lid and put the container in a plastic bag. No ants appeared inside the bag but outside the container, and thus we concluded that the ants couldn't escape through the holes. Our new containers required us to not only move our 30 frogs, but also to replace all 240 ants in the containers, especially since many ants were dead anyway. We had plenty of Paratrechina ants infesting the lab, but our control Pheidole ants had mysteriously disappeared from the place where we had originally trapped them. Thus, Andrés and I went on a two-hour quest in the woods to find new control ants, which build their nests on Arecaceae and Cyclanthaceae leaves. Finally, we were able to set up our frogs in their new containers. Hoping a change from the indoor classroom environment would also help, we put some of the containers in the woods and some in an outdoor shadehouse. A few hours later, I went to count ants in the containers in the woods. I picked up the first container and counted 10 ants - the eight ants we had placed in the container plus two different, smaller ones. Baffled, I continued to count ants in the other containers, obtaining similar results. Slowly it dawned on me that although our ants couldn't get out of the containers, smaller ants living in the forest could get into them. Why they would do this is beyond me, but the end result was that we had to replace ants in about 15 containers yet again. Later, after dinner, we went to count ants in the shadehouse containers. Not only had no ants still been eaten, but a couple of frogs had died because we were unaware that the shadehouses can get extremely hot during the day. Discouraged and frustrated, we let the remaining shadehouse frogs free and finally went to bed around 10 PM.

^A few of our containers, complete with frog, ants, and wet cotton ball for moisture. We separated them with cardboard because the frogs are very visually sensitive.

Day 4
On the fourth day, we finally got another good break. Ronald found me after breakfast, excitedly reporting that he had finally found Brachymyrmex ants crawling around on an Inga plant outside his office. He carefully showed me which ants to look for on the plant, as there were many ants besides Brachymyrmex present. The ants in question were impossibly tiny - less than a millimeter long, black, and not terribly common on the plant. We tried to trap them, but the bigger ants on the plant quickly monopolized the honey in the trap. The only way to catch them, then, was with an aspirator. Now that we were catching miniscule ants, I added about six layers of mesh to the aspirator and went at it. For about three hours I stood in front of the Inga plant, watching carefully for Brachymyrmex to come crawling by and then quickly sucking them up. Each time I trapped four, I put them in a plastic container, to which Andrés added four control Tapinoma ants that we trapped behind the dining hall. After sucking up around 120 ants and catching 30 more frogs, we finally had 30 more frog-ant setups. Problematically, though, still not a single ant had been eaten, and thus we had zero data. At this point we were fully expecting to write a grant proposal instead of a paper, which was our professor's solution to the zero-data problem.

^The end of the aspirator (about 1 cm diameter) and a Brachymyrmex, which is barely visible as a little black dot on the leaf.

Day 5
On the morning of the fifth day, we went to the classroom to count the tiny ants in our containers. We had taped shut each tiny little hole in the lids, so there was no way the ants could escape (or enter!) this time. We could hardly believe it when we started counting ants and - low and behold - we counted less than eight in most containers! We set free the frogs that had eaten ants, and came back later to do more counting after more frogs had eaten. Finally, we had data - hallelujah!

The Ending
In the end, our data showed pretty clearly that the frogs didn't prefer either type of ant (Brachymyrmex or control Tapinoma) over the other. This was still an interesting result, and much of our presentation and papers focused on finding explanations for it. Our advising professor, Erika, was proud of us for sticking with what she said was the most interesting poison-dart frog project she had seen in 15-ish years. The second IP is scheduled for our last site, Palo Verde - hopefully that one will go at least a little more smoothly :)

Friday, October 3, 2008

La Selva: La Aventura

Here comes the first set of La Selva adventures.

^Me and my mad poison-dart frog-catching skills... explanation for that to come later.
^A typical trail at La Selva, although many trails are much narrower or and/or unpaved.

^Golden orb spider. They're very common here, and their webs are stronger (can withstand more force/diameter) than steel.

Our first day at La Selva was Costa Rica's independence day, so we spent the morning in town watching a parade. It was insanely hot, especially compared to the frigidness of Cuerici from which we had come. There were lots of school bands and dance groups, and I was especially impressed with the childrens' drumlines. It was fun watching the parade alongside the residents of Puerto Viejo, as we have had little interaction with Costa Rican people thus far.

Of course, during the first couple of days, we all took advantage of the hot weather and presence of the river to go swimming. At one point a few people swim "with" a cayman, although I was working at the time and unaware of the swimming escapade. A few of the guys subsequently decided to go back down to the river, essentially to stalk the cayman. Naturally, the cayman swam swiftly away upon sighting people - this after the guys spent a good half hour trudging down the densely forested, steep riverbank. It was a pretty hilarious sight to watch from the bridge above.

^Billy, Andrés, and Tim failing miserably at stalking the cayman.

During the early part of our stay here, we took a day trip to the local Dole banana plantation. We learned a lot about the history of bananas in Costa Rica (which we had studied previously in depth), the banana industry, and the process of growing and harvesting. The most entertaining parts, however, were probably a) Tim climbing up a ladder and trying to put a bundle of bananas in a bag and b) watching the mules pull trains of bananas through the plantation.

^Tim bagging a banana bunch.

^A mule pulling the "banana train."

^Boxing up bananas to go to Norway (yay!)

One cool aspect of the OTS abroad program is faculty-led projects, or FLP's. In our second week at La Selva, we had two of them. One was a study on the correlation between rates of herbivory, elevation, and plant diversity, and the other was about apogeotropic roots (roots that come out of the ground and climb up trees). Although I was in a group in charge of presenting the results of the herbivory study, my more adventurous/hilarious experience was a result of the apogeotropic roots study. In brief, we hypothesized that roots would tend to climb up trees with "nutrients funnels" - i.e., palm trees whose leaves capture falling leaves and create a "funnel" of nutrients from their decay. Throughout the project, we would occasionally trace these roots from the tree they were climbing to the tree from which they originated. This typically entailed digging in the ground to follow the root for a few meters at most. At the end of the day when I was working on the project, four of us (Claire, Becca, Tim, and myself) stayed behind to dig one last root to its source tree. We followed the root along and under the paved trail, only to discover about 45 minutes and about 20 meters later that it simply joined into a root that another group had dug previously but had abandoned as the root dove deep into the ground. After all of our efforts, though, we weren't about to give up on finding the source of the mega-root, and by this time the visiting professor who was in charge of the project was especially curious as to the source tree species. The four of us continued digging after the root, which after delving about a foot in the ground miraculously returned to a few inches below the surface. A few hours and FIFTY meters later, we traced the root straight to a huge tree of the Moraceae family. Both the tree and multiple sections of the root had the same milky latex, so we knew we hadn't taken a wrong turn along the way. Remarkably, that one root led to and climbed four different nutrient-funnel palms. By the time we finished, it was almost dark, and we were completely covered in mud and sweat... however, we still managed to sing our newly-learned (thanks to our professor) "Tropical Biology Blues" song all the way back to the dining room for dinner.

^Tim, Becca, and I digging away. Claire was playing photographer for the moment.


Today is our last day at La Selva - we leave at 8 AM tomorrow morning - so last night a few of us went on a night hike, mostly with the intention of finding a fer-de-lance (highly poisonous snake that inhabits La Selva). Although we failed miserably at finding a fer-de-lance, we did manage to find a small slug-eating snake and a red-eyed tree frog. The red-eyed tree frog gave giraffes a serious run for their money for the position of Hilary's favorite animal... winner as yet undecided.

^Billy with red-eyed tree frog... AWESOME.

Wednesday, October 1, 2008

La Selva: Flora & Fauna

On September 15, we drove by bus for five hours from Cuerici (altitude 2700 m) to La Selva Biological Research Station in northeastern Costa Rica (altitude 500 m). La Selva is owned by OTS, and is a very well-known and productive research station. I've been amazed by what a large proportion of tropical biological research has been performed at La Selva as I've been searching the literature for various assignments since we've been here. Many researchers live long-term on-station, and there are even a couple of famous British photographers currently living here and working on a book.

^The bridge we cross to get to and from class and the forest. Sweet, right?

Here's a blurb about La Selva from the OTS website, since I'm too lazy to come up with one myself:

"At the confluence of two major rivers in the Caribbean lowlands of northern Costa Rica, La Selva comprises 1,600 hectares (3,900 acres) of tropical wet forests and disturbed lands. It averages 4 m (over 13 feet!) of rainfall that is spread rather evenly throughout the year.
La Selva was originally established in 1954 by Dr. Leslie Holdridge, as a farm dedicated to experimentation on mixed plantations for the improvement of natural resources management. It was purchased in 1968 by the Organization for Tropical Studies and declared a private biological reserve and station. Since then, it has become one of the most important sites in the world for research on tropical rain forest. Over 240 scientific papers are published yearly from research conducted at the site."

Our accomodations at La Selva are 6-person bunk rooms, and we are lucky in that we have five of them for 22 people (yay!). There are only three showers & toilets, so every time we have an afternoon soccer game there is a mad (and hilarious) rush to get to the showers first. La Selva is definitely the most hot and humid place I have ever been - most of the time you feel like you're walking around in soup, and we all sleep with very few clothes on and usually no covers. If there was any doubt that we were in the rainforest at Las Cruces, it's certainly gone now.

Our first week at La Selva involved a lot of lectures, hikes around the forest, and general marveling at our surroundings. Since it's looking like I'm going to end up posting a mildly ridiculous number of pictures of La Selva, I'm going to keep this one to flora and fauna and save the adventures for the next few posts....

^Peccaries. They are literally everywhere, and they smell terrible.

^Leaf-cutter ants. They are also literally everywhere, and I'm convinced they're going to take over the world, one little slice of leaf at a time.

^Really awesome bug I stumbled upon (mantidae).

^Camoflauge, anyone? Pupa.

^I doubt any of you are going to believe me, but this is actually an insect we found. Species is Fulgora laternana. I think it looks like a dinosaur.

^Millipedes. Also everywhere, and about 90% of the ones I've seen have been mating. As a result, most of the guys have declared their intentions to become millipedes in their next lives (what'd you expect?)

^Howler monkey! This one was randomly climbing on the bridge cables, but we see them a lot around the forest. The most interesting thing about them is the intensely creepy howling sounds they make.

^Extremely large stick bug... the finger is the same distance from the camera as the bug.

^Leeeee-zard! (Jessie, that was for you.)

^Cayman (see it?). A few of my friends went swimming in the river with them, but unfortunately (luckily?) I was working at the time and missed out.


^Stilt roots - I have no idea how some of these things remain standing.

^Strangely pretty fungus.

^Bats! Bats, also, are everywhere, and when I go running on the trails in the evening I often shield my face with my hand for fear that one will fly directly into my face. Of the 210 mammal species in Costa Rica, 110 are bats.

^Sloth! I saw it last night hanging from a bridge cable on my way back to the cabin to go to bed (at 9:30... haha.) That brings my lifetime total sloth sighting count to two - the first being last summer in Brazil.