Wednesday, September 30, 2015

Arachnaphobe studies daddy long legs, survives

Opiliones are not spiders. That was the logic my group members used when they were trying to convince me to conduct our independent project on a specific type of daddy long legs. I’m not a fan of spiders. I understand that they are an important facet of many ecosystems (including those found in La Selva), but something about them makes my skin crawl. And while it is true that these arachnids aren’t spiders (which belong to another order entirely), I wasn’t especially enthusiastic about the choice of study organism. In fact, I dragged my feet during every step of the planning process, debated leaving the group, and complained more than I would like to admit. Despite my initial reluctance, I ended up enjoying the data collection process immensely, which is at least partly (if not mostly) due to the fact that it gave me a legitimate excuse to poke living organisms with a stick.
We chose to study opiliones because they exhibit two interesting defense strategies: autotomy and aggregation. Autotomy is the ability to voluntarily drop limbs in the face of predation (for example: some lizards can drop their tails). Aggregation is the tendency for members of a species to gather together into large groups. Aggregations of opiliones will all vibrate simultaneously in the face of perceived danger, which is meant to confuse and intimidate predators (it’s definitely a striking visual when you see it). Since opiliones commonly lose legs from autotomy, we wanted to see whether the number of legs on a predated individual affects the response of the group (whether they disperse, vibrate, or do nothing). We thought that opiliones that were missing legs might be more likely to react to stimulated predation (being poked with a stick) and inform the group, since they were not as na├»ve to the costs of predation. We wandered around La Selva poking aggregations of opiliones and recording the groups’ responses. After sampling 119 groups which ranged in size from 3 to 165 individuals (2,454 opiliones total!), we found that groups did not respond differently based on the number of legs of the individual poked. We did find that larger groups were more likely to vibrate while smaller groups were more likely to disperse, which makes sense given that group vibration is more intimidating if the group is large.
I really enjoyed the opportunity to design and execute an independent research project, and I learned a lot about fieldwork in the process. I’m grateful to my group for encouraging me to stick with the project when I initially wasn’t interested; I found that while I still don’t like spiders, I don’t mind opiliones because after all, they’re not spiders.

Rose Hinson
Duke University

Tuesday, September 29, 2015

Balancing act - addressing the needs of man and nature

Hou! Hou! Hou! I hopped out of bed and made my routine trip to the dining hall as calls from the howler monkeys in the distance signaled that it was time for a new day in La Selva to begin. Nature’s very own alarm; I much rather wake up to this than to the digitized tones emitted by my phone each morning. The only benefit of the latter was the fact that it can be snoozed. Looking down at my bowl of chocolate rice krispies and the banana that sat next to it, I was reminded of a line from a book that I have been reading over the past few weeks: “It is apparently difficult for us all to see the connection between the knife that slices the banana into our cereal bowl and the chain saw that slices tree trunks onto the rain forest floor.”
Having grown up with a fondness for biodiversity and wildlife, I have often been a strong supporter of conservation programs and envisioned myself as someone who would contribute to the cause in the future, either in the shoes of a naturalist, ecologist or conservationist. Yet this quote from Breakfast of Biodiversity reminded me that at the same time, I am also a member of a consumerist system that contributes directly to the destruction of the natural places I wish to protect. Anecdotes from this book, coupled with a visit to a local banana plantation, showed me how consumer behavior, of which I am a part, leads to wastage of produce from plantations that drives the need to convert more rainforest to plantations.  Despite having some reservation with regards to some of the points brought up by authors Vandermeer and Perfecto, I agree with them that the way forward in conservation is not purchasing tracts of land and disallowing alternative land uses. Rather we need to approach the issue as a systemic one, unraveling the interconnected links and addressing it within its own framework.
Of the issues we have discussed this semester, one that very much remains an enigma to me is balancing ecosystem protection and catering to the needs of people. Having grown up in a relatively affluent environment, it is easy for me to demand that people cut back on consumption to protect forests. Yet at the same time, I have come to realize the importance of being cognizant of the fact that the very people living around the forests do not enjoy similar luxuries and privileges. With few options for them to make a livelihood with, it is not difficult to see why they would choose to carve out a living from a “free” natural resource surrounding them – the forest.
Although I presently do not have any solutions to how such a balance can be achieved, our discussions on conservation issues have given me an awareness that has spurred me to aim to be part of the conversation and hopefully somewhere in the near future, join scientists and policy makers in reaching a compromise and delivering a promising answer.
Donovan Loh
Duke University

Adventures with cane toads

When we first arrived at La Selva Biological Station, I had no idea what kind of antics I would get up to in the name of science. The other night at around 9 pm, I found myself wading through the putrid mud of an area with former agrochemical exposure attempting to locate and capture cane toads (Rhinella marina). For those readers who have not had the singular pleasure of working with cane toads, I would like to note that they pee rather forcefully upon capture (a questionably effective defense mechanism). This particular characteristic, coupled with the impressive ability of mud to seize and retain rubber boots made for a hilarious, if not slightly catastrophic night.
The following day we placed the toads one by one onto a makeshift treadmill to measure their endurance. We also collected blood samples in order to perform blood counts and assess their parasite loads. Another group of students performed the same evaluations on cane toads collected from areas with no (or less) agrochemical exposure. The endurance levels and parasite loads of the two groups were compared to determine whether cane toads living in a region exposed to monocropping and agrochemicals differ from those living in a biological preserve. 
Cane toads collected from agrochemical exposure areas had both a higher parasite load and a lower white blood cell count. One potential explanation for this finding is that agrochemicals could be suppressing their immune responses. However, no difference was found in endurance of the groups, which makes sense given that cane toads are highly resilient to increased parasite loads.
Prior to this semester I had plenty of experience working in labs, but had never really experienced data collection in the field. This project opened my eyes to just how intense (and amusing) fieldwork can be. And on a totally unrelated note, we saw a juvenile puma on our drive back from collecting toads! I live in a region of California where puma sightings are not uncommon, and had always wanted to see one. It was an unexpectedly beautiful conclusion to a rather absurd evening. 

Rose Hinson
Duke University