Monday, October 27, 2008
Some stolen photos... :)
Sunday, October 26, 2008
The Frog and Ant Project/Saga/Disaster

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.


^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.
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




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.
^SUCCESS!
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

^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.







^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.