Ants on Sweet Plants

We’re in the middle of independent projects and, as usual, there are more problems when we are out in the field at 5 am than when we are comfortable chatting about our plans at dinner. It’s part of science, I guess. I am working on a project with Erin & Jess that looks at how plants defend structures in which they have invested different amounts of energy. Let me explain the model system so that this makes more sense:
Our organism is Ipomea carnea, a morning glory species that flowers in the dry season and is prevalent in disturbed areas around Palo Verde. The leaves and stems contain toxic or impalpable compounds that deter herbivores, but their flowers and buds are more vulnerable. To defend their floral structures, they have extrafloral nectaries on near the petals that secrete (you guessed it!) nectar that attracts ants and wasps. Researchers suspect that these aggressive insects around the buds deter herbivore from munching. Okay, so that is plant defense.
Some defensive mechanisms are constitutive, that is they are produced all the time. For examples, plants constantly produce toxins in leaves, prickles on bark, or nectar in extrafloral nectaries. These defenses and others can be induced, or increased if the plant is threatened by herbivory. So plants will produce more toxins, prickles, or nectar if they are damaged by herbivores. That is induced plant defense?
But do plants induce defenses equally across all of their structures? Would they defend a little bud, in which they had invested little energy, as vigorously as they defend a large bud, in which they had invested a lot of energy? This is the question we are asking. We are comparing the extrafloral nectar production among large and small damaged and undamaged buds. Straight forward, right?
This means that Erin, Jess, and I roll out of bed at 4:45 am to get to the nectaries before the wasps take their share and collect droplets of nectar in little capillary tubes. And we also will be counting ants on plants for 20 minutes at a time. The observation period will not be quite are intense as Ben’s methods for his project, but it will still be tedious. But that is part of fieldwork. At the end of the four days, I think we will get some really interesting results.

Morning Glorys and Bees

For the next two days, we are working on faculty-led projects, which means that we are doing the data-collection and grunt work for projects design by visiting faculty members. This morning my group worked with Kathleen Kay, a plant evolutionary biologist from UC Santa Cruz. (And, just for more evidence that its a small world, she hired Allison Louthan to work in her lab, a Grinnellian who graduated last year who started the Ecology & Evolution Journal Club that Ben and I went to.) She's very approachable and laid-back (very Californian). Her project focused on who extrafloral nectaries, or sources of nectar outside the flower, can protect the flower against nectar robbers, like carpenter bees, who bite a hole in the bottom of the flower and drink nectar without pollination, and also influence pollination visitation by little soliary bees. Extrafloral nectaries generally attract aggressive insects like ants and wasps by providing food in exchange for defense from insect herbivores. She choose the morning glory flower as the study subject since they are one-day flowers (we don't have to deal with florivory—herbivory on flowers—from the day before) and another researcher had documented extensive carpenter bee damage (up to 50%) on the flower. The hypothesis is that when the EFN incentive is turned off by making stopping the flow of nectar or preventing insects from reaching the flower, the plant with be more vulnerable to floral herbivory. So that was the original game plan.

We got up and out the door at 5:15 am and found flowers that were about to open. We covered the EFN on some of the flowers with nail polish to prevent the nectar from attracting ants and left the EFN on the others. Then we sat and watched. And sat and watched some more. A large chunk of fieldwork is tedious waiting in uncomfortable positions. So waiting for the bees to fly in and wiggle themselves into the flower was good practice. Despite the tedium, I enjoyed the experience; when you sit quietly, you see a lot of neat details that you otherwise miss. I saw a gorgeous green spider huddle down below the white blossom; unfortunately, I did not see him catch anything. I heard a rodent squeaking in distress and then saw a snake slithering away in the underbrush. And I stuck my nose down the flower to watch the bees waddle around collecting nectar. Unlike the bumblebees that you might conventionally think of as the prototypical bee, these wild bees are very small (~ 3 cm), shiny, and black. They are usually solitary, not clonal and they usually eat pollen, not nectar. So the bees spent more of their visit doodling around near the anther to gather pollen and less time wiggling to the base of the flower to drink nectar. Pretty neat. No one, however, saw a carpenter bee and only a few people observed herbivory. So we'll see what the data looks like this afternoon.

And tomorrow morning, I will be waking up at 5 am to watch howler monkeys! Hooray!

Hiking! Bat Caves! Watering Holes! Rocks!

This was a day of directional challenges for Ben and Hart. We started off with one of our friends to find a water hole about 30ish minutes from the station. The journey took about an hour. We spent some time there listening to the howler monkeys in the trees, watching the cane toad in the stream, and scrabbling over some rocks. It was a lovely break from the hot sun on the road. Then Jess headed back to the station for lunch, while Ben and I trotted up to find a bat cave. Yeah, bat-cave. Super cool, right? Except it proved to be quite elusive, so we spent the rest of the morning exploring different trails and watching wide-eyed (and with a wee bit of "miedo") as white-faced monkeys screamed as us and shook branches in the canopy. This species travels in groups of twenty--quite a lot of monkeys in a barrel--and are fully omnivorous, eating the infants of other monkeys, fruit, leaves, eggs, etc. It was quite amazing. After we finally declared the bat-cave to be lost, we hiked up to a rocky look-out point. We could see the whole park with the marsh in the basin and deciduous forest along the mountains. Very beautiful.

Rice & Sugar-cane Fields

We spent the morning in the hot, hot, windy rice and sugarcane fields in a flat valley next to Palo Verde National Park. The area was given to small farmers in 10 ha plots around 20 or so years ago by the Costa Rican government as a rural development project. To irrigate the land, water left-over from the Arenal dam project has been diverted to the valley through a series of canals, some spanning more than 30 kilometers. So this is a hugely impressive public works/agricultural reform project--but (of course) it also creates some problems for the park.

Heavy levels of pesticide and fertilizer use pollute water that eventually flows into surrounding marshes and the Tempisque River, the largest watershed in northern Costa Rica. The chemicals may not be directly harmful, but they can build up in the food chain from insects or rodents to birds or fish and eventually back to people. And, of course, there are other problems with nutrient build-up clogging up aquatic ecosystems or the agricultural monocultures supporting artificially high pest populations.

Migrant issues also come into play with the sugarcane plantations. Unlike rice, sugarcane only demands a large work-force at establishment and harvesting. And this work is incredibly tough: hot sun, long hours, and heavy labor. This means that the companies that own the land want to import workers and then send them away and that the workers have to be willing to tolerate intense conditions. So Nicaraguans usually come over to take these jobs. On one hand, they are subject to unfair working conditions (little access to drinking water, poor living facilities, limited access to health care). On the other, some Costa Ricans implicate these immigrants with increased crime rates and over-extended public health. Sound familiar?

So it was a very interesting, but also depressing and exhausting field trip. For the rest of the day, we were encouraged to contemplate our independent project topics. I'm still contemplating. On our day off tomorrow, Ben and I have planned to do some hikes around the park to check out different sites and study organisms and brainstorm ideas. Hopefully our adventures will inspire a solid research topic.

Cuerici & Palo Verde

For the past week, I have been free of Internet access at the Cuerici Biological Station, a small, privately owned reserve at high elevation. The conservation area was started by Don Carlos, a farmer whose family has owned the land for generations, and seven other Costa Ricans. He has had a very interesting relationship with conservation. Don Carlos only completed second grade and then spent most of his young life making charcoal by burning off sections of the forest and hunting. This was the traditional lifestyle of many people in the region and, before the population expanded dramatically, it was reasonably sustainable. The forest and its animals had time to recover between disturbances.

Now, however, the burning is devastating for the mountainous ecosystem and families continue to burn to clear land for agriculture or scare animals out of the forest for hunting. Global climate change and habitat destruction have just exacerbated the problem by making the land hotter and drier. Don Carlos, among others in Costa Rica, realized that, although fire had been a traditional way of life, it was killing the ecosystem, threatening communities’ future livelihoods and natural beauty. So he joined with other citizens to purchase farm that his grandparents had originally worked and several hundred (?) hectares around it of remnant montane oak forest.

It’s neat because this ecosystem looks little temperate forest back home--oak trees, moss, cool temperatures, some rain clouds—but it’s also quite different as the oak leaves are smaller and un-lobed and the soil is much more fragile. The trees grow so slowly that one around little less than a meter in diameter—the size for harvesting—could easily be over a hundred years old. This makes oak forests impossible to harvest from sustainable, unless your company’s plan is looking 100 years into the future. So Cuerici is a special place because it protects a very fragile, irreplaceable ecosystem.

It is also special because part of the biological station is also a trout farm. So this is a conservation area that both uses the land and preserves it. Pretty unique in Costa Rica. Like Don Roberto (the coffee farmer from Agua Buena, whose coffee you should starting buying, hint, hint), Don Carlos cares deeply about the land and really emphasizes the one should only take what one needs. All of the students really admire and respect Don Carlos. He is a wonderful and special human being. But the trout farm is problematic; if trout escape from his land in the dry season—which is a rare event—they can devastate the aquatic ecosystem by gobbling up native species. Don Carlos and many other farmers were paid by the government to start these trout farms a decade or so ago as an economic development initiative. (Hint, hint, this is why governments need to actually listen to scientists, not special interest groups. Any ecologist would have known that introducing an aggressive species is a mistake. Just like any good scientist correlates greenhouse gases and global climate change with human-produced pollution.) So it’s complicated, but overall, I would call Cuerici a success story. Private citizens conserved a fragile ecosystem while, at the same time, providing economic opportunities for families in the community and opening the land up for local and international students.

And it was so wonderful to be cold again. I never thought that I would say that.

The next biological station is Palo Verde in Guanacaste, a heavily degraded region in Costa Rica’s northwestern corner. Most of the land has been converted to cattle ranching and, in the tropics, cattle tear up the pasture land, leading to erosion and fragmenting fragile forests. It is really sad. The bus-ride gave me even more reason to eat locally; I don’t want to contribute to a system that turns forests into eroded, tragic pastures to make hamburgers. Anyway, the station is within Palo Verde National Park that contains a gorgeous marsh and gorgeous dry tropical forest. Many of the trees, especially in the secondary forest, are deciduous in the dry season. Many trees also flower in the dry season, so some parts of the forest are exploding with gorgeous blossoms on naked trunks. There are an amazing number of large animals here. At the other sites, I mostly looked at insects and plants, but in less than 2 days at Palo Verde, I have seen a crocodile, egrets, herons, white-faced monkeys, howler monkeys, and iguanas. It’s pretty neat.



The marsh is absolutely gorgeous. It stretches out for miles to a large river and then ends at enormous mountains. It looks like a landscape from a Georgia O’Keefe painting, especially at sunset when all the light is reflecting off the marsh water. It’s home to an unbelievable number of birds of all shapes and sizes and foraging habits. Watching the marsh from the boardwalk is overwhelming. And the marsh is another interesting system because it must be actively maintained to prevent aggressive water hyacinth and cat-tails from filling in the open water and scaring away all the wonderful waterfowl. So the crew at Palo Verde has to regularly mow the area with huge tractors. They have also introduced cattle adapted to hot, marshy conditions to try to keep down the invasive species. It’s has not be terribly successful in the marsh, but they do keep down other terrestrial invasive species. So cows aren’t all bad; it just depends on the environmental context.

So it is wonderful here, even if it has been hot and sweaty. And I went on my first jog and played soccer today. It was so much fun!

El Camino a San Vito

Monday is our day of rest from biology in the tropics. So Ben and I went hiking through the rain forest to San Vito, the small mountain town about a 20 minute drive from the station. The hike was a lovely journey through ecological principles. We saw all the plant families that we will be tested on tomorrow morning. Heliconiaceae: think bananas. Great big leaves that rip easely; this may help cool the leaves, said Susan our plant specialist professor. Maranstaceae: the stems have a "pulvinus" or a flexible piece of tissue that allows the plant to move its leaves to either catch more sunlight or pull together to stay warmers at night. Piperaceae: the seeds are black pepper! The leaves are noticeably oblique and the joints are knobby. We also walked through different kinds of ecosystems wiht different microclimatic patches. Some areas were hotter or wetter or sunnier than others, creating what Vince, my Grinnell professor, would call a "patchy world" or "dynamic mosaic." Different places for differently adapted species. Patches were under different stages of succession: primary forest with enormous, ancient trees; secondary forest with scraggly pioneer species; and lovely gaps for sun-lovers. Epiphytes are still my favorite. These plants perch along tree branches, putting out roots to catch falling litter and water. The collections can build up into several centimeters of soil on the branches. Some tree species will even produce aerial roots to benefit from this extra mat of soil. So, long story short, I spent most of my day off reveling in ecology.

And (this is exciting!) a graduate student working out at Las Cruces offered to take me on as a research assistant for the summer--if I can find money for housing and rice and beans. He is studying successional dynamics in sites with and without large mammalian predators. And he also plays frisbee. The position would be lots of good fieldwork, plant identification, and hikes. That sounds fabulous. We'll see what other opportunities I can find along the way.

Pictures! Pictures!

Cup o Joe

Okay, the short version! 15 minutes until class. We spent the morning with Robert Jimenez, a sustainable coffee farmer in Agua Buena, a small town in the mountains a 20 minute drive from the field station. His coffee "finca" looks more like a forest, with banana and guava trees shading coffee plants. He has replanted degraded pastures with rain forest vegetation as well. His farming practices produce coffee and food, but they also provide essential ecosystem services: creating habitat for birds and native pollinators, preventing erosion, maintaining watersheds, sequestering carbon. As Roberto showed us his land, it was very clear that his heart is in this issues, in enriching the "medio ambiente," rathering than turning a profit.



The night before we watched a short film about the economics of coffee production. As most of us have probably heard before, the producers make very little profit for each cup of coffee that we buy in the United States and they also absorb all of the risk. When coffee prices drop, their income drops. To provide farmers with a sustainable, just income, the farmers and community activists in the US have started various direct-marketing co-operatives, in addition to the fair trade certifications already in place.

Roberto Jimenez is a part of the CoopePueblo, a cooperative that links over 50 farmers in the Agua Buena region to consumers in the US. The coffee is wonderful and its production supports families and healthy land practices in Costa Rica. I encourage you to check out the website and place an order: http://www.unatazacompartida.org

Las Cruces

This is my first full day at Las Cruces and I've had a wonderful time so far. An extensive tropical botonical garden surrounds the lab, dorms, and dining area. I've never seen so many bromeliads, flowers, palms, and ferns in one place before.

In the morning, we took a short hike through some rain forest fragments bordered by thirty or so year old, degraded pastures. We talked about "edge effects," or how the microclimatic conditions (ie, temperature, wind speed, humidity, sunlight) when part of the forest is removed and how these abiotic changes affect the plants and animals that live there. The bottom-line is that what happens at the edge of fragments penetrates into the forest interior affecting diverse, multi-species interactions. So the whole system, not just the jaguars or the trees, are impacted.

For one of the homework assignments, I have to collect and identity 10 insects at each field station. So Scott, another OTS student, and I caught some bugs after lunch. Stingless wasps that build elegent nests attached to walls. Bluish flies feeding on banana flowers. Unsuspecting beetles. They are in the freezer, convienently dead in the name of science to make the identification process easier. Mauricio, the Costa Rican professor, will show me the ropes of bug identification tomorrow morning. Plant taxomomy is second learning curve that I have to overcome. Susan, the other professor, will take me on a walk this afternoon to teach me all the vocabulary.

Estoy in Costa Rica! Hooray!

8:34 am: Arrive with Mama at Pittsburgh Airport for a 11 am flight to Houston. Yeah, we're that good.
9:43 am: Uh, oh. Flight delayed until 1:00. Good thing that I had a four hour lay over in Houston.
3:00 pm: Arrive in Houston.
6:05 pm: Leave Houston.
9:45 pm: Arrive in San Jose!

Tomorrow morning a good soul from the OTS office will fetch me from the hotel and drive me 300 km to Las Cruces. So tomorrow night, I'll be eating rice and beans in the rain forest. Sweet.

To Costa Rica or Bust!

Okay, my second attempt at international travel. I think that I'll make it this time.

Before I get on the plane at 11:05 tomorrow morning, I still need to: 1) pack (uh-oh, this could be an adventure), 2) make myself plane-food, 3) run around the house in a state of panic, 4) hug my mama, 5) hug my cats, and 6) call Grinnell friends.

Wish me luck.

If all goes as planned, I will arrive in San Jose at 9:45 pm, get picked up by OTS staff and brought to a hotel, sleep (or not sleep because I will be too excited), and then get driven 8 hours to Las Cruces the next morning. So I will be in the jungle by Thursday afternoon.

From reading Ben's Flog, I'm also realizing how unbelievably behind I will be. I've diligently done most of the readings for the semester, but how do I make up +15 hours of field work to learn insect, flower, plant, and fruit taxonomy? Oh dear.