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Student projects in Costa Rica – part 2: From poison dart frogs to cannibalistic tadpoles at La Selva Biological Station

The January-term course in Costa Rica, Introduction to Field Ecology course, is over. I’m sure everyone is happy to be home, but I hope the memories of the course will stay with people for a long time. I’m finally getting my life in order again, and I thought I would share some information about our final stop on the course – La Selva Biological Station – and post abstracts from the amazing projects that folks did there.

lunch time for our group at La Selva

an eyelash viper, picture from Tyler Abrahamson

La Selva was a great place for our course to visit. La Selva itself is fairly small (about 1600 hectares) but it is connected to the massive 36,000-hectare Braulio Carrillo National Park. The large combined area and the elevational gradient from lowlands to the 3500 meter peaks in Braulio Carrillo make this area a unique conservation area on the Caribbean slope. The flora and fauna are very diverse: there are over 700 species are trees at La Selva, a lot of beautiful snakes such as the eyelash viper (that many of us saw) and the dangerous and aggressive fer-de-lance (that one of us stepped on!), thousands of arthropod species such as the army ant Eciton burchelli (video), charismatic amphibians like the strawberry poison dart frog (see below), and more than 400 species of birds (representing almost half of Costa Rica’s bird species) (here’s a gratuitous baby peccary video). There’s also extensive infrastructure at La Selva. There is also modern lab space, comfortable living quarters, a cafeteria, and an extensive trail system. Some of the trails through the forest are even paved. La Selva is really wet (it gets about 4 meters of rain a year) and a lot of foot traffic on paths would quickly degrade the surrounding area. Paved paths also make it easier for researchers to travel to their study sites; the station even rents bikes that you can ride along the paths (here’s a video from some of our group). The diversity and infrastructure is part of the reason that La Selva is one of the most important places for tropical research in the world: since the station was established by the Organization for Tropical Studies in 1968, there have been over 1600 scientific papers published based on research at the site.

Our group contributed to this research output with 4 great projects. Here are their abstracts:

Factors that influence territorial calls in the strawberry poison dart frog, Oophaga pumilio

Katelyn Bojan, Maya Peters, Danny Oseid

a strawberry poison dart frog - not for licking

There has recently been growing concern regarding the potential effects of global climate change on the diversity and population density of amphibians in the tropics (Whitfield et al. 2007). Consequently, it is important to understand the behavior and lifestyle of tropical amphibians for conservation purposes. One amphibian species that is especially important is the charismatic Oophaga pumilio, the strawberry poison dart frog (video). This organism communicates with potential mates and competitors in form of bright coloration and territorial calls. Here, we investigated the factors that influence these signals by addressing: 1) the effect of call intensity and length on the magnitude of neighbor response and 2) the traits of frogs that determine response intensity. It is unknown how these frogs respond to varying calls and how they allocate their energy towards the expensive signals of bright coloration and territorial calls. There are two alternative hypotheses concerning allocation of energy towards these signals. The tradeoff hypothesis suggests that brighter, bigger frogs will call less, whereas the handicap hypothesis postulates that the highest quality individuals will have the best genes, and therefore will produce both signals equally well. We predicted that 1) longer and louder calls would signify a greater relative threat and evoke greater response calls and 2) signaling intensity would fit either the tradeoff or handicap hypotheses. We found frogs were found in disturbed areas and classified them by size (small, medium, or large) and brightness by a scale. We then played vocal recordings of Oophaga pumilio near identified frogs at half or full volume and for a length of 20 or 60 seconds, and recorded time to respond and call duration. We found that louder and longer recordings both evoked a delayed response (F_3,56 =6.17 , p= 0.0160; F_3,56 = 3.80 , p= 0.0562) and a significantly longer response call (F_3,56 =4.24, p= 0.0440; F_3,56 = 3.83, p= 0.0551). These results suggest that louder, longer calls signal closer, more aggressive opponents, and frogs recognize these as a greater threat. In addition, larger (F_2,26 =4.28 , p= 0.0246), and brighter (F_3,26 = 2.94 , p= 0.0520) frogs generally produced longer response calls. This result is consistent with the handicap hypothesis (but not the tradeoff hypothesis), suggesting that the highest quality individuals in the population are both brightly colored and have a good territorial chirp. Overall, this study demonstrates the complexity of Oophaga pumilio signaling behavior and indicates that this organism is an appropriate model system for studying behavioral ecology. Based on these findings, we hope that continued effort will be taken to conserve this species in the long term.

Whitfield SM et al. (2007) Amphibian and reptile declines over 35 years at La Selva, Costa Rica. Proceedings of the National Academy of Sciences, USA 104: 8352–8356.

Fruit Eating Fish: Pattern recognition versus initial quality assessment in Brycon guatemalensis

Evan Nolander, Tyler Abrahamson, Mark Painter, Leah Ruhland

            When foraging, animals need to make a decision on when food is worth attempting to acquire. Food quality can often be assessed directly by sampling. However, sampling opportunities may be limited when competition for resources is intense; how such competition affects assessment strategies is poorly understood. Here we examined assessment behavior in Brycon guatemalensis, a frugivorous river fish that groups in large schools underneath fruit trees. We predicted that B. guatamalensis would rely upon a system of pattern recognition for areas with elevated amounts of high quality food, rather than individual assessments of each piece of falling fruit when deciding whether or not to attempt to consume it. We conducted 3 tests to evaluate B. guatamalensis foraging behavior; we replicated each tests at 3 sites. First, we assessed how food quality affects foraging by adding either “high quality” banana pulp or “low quality” banana peel at 20-sec intervals in distinct locations. We found that significantly more fish responded to the high quality food (mean=8.19) than to the low quality food (mean=2.00, t=10.671, df=126, p<0.001), and that high quality food was consumed in less time (mean=3.29 seconds) than was low quality food (mean=13.40 seconds, t=8.883, df=126, p<0.001). In a second test, we examined the timing of food assessment by adding food with an alternating pattern of high and low quality at 20-sec intervals in distinct locations. We again found that significantly more fish responded to the high quality food (mean=5.27) than to low quality food (mean=2.95, t=4.909, df=131, p<0.001), and that high quality food was consumed in less time (mean=2.66 sec) than low quality food (mean=12.45, t=-8.128, df=131, p<0.001). Results from the alternating and non-alternating tests were compared using a two-way ANOVA, and the differences between number of fish responding to both high quality food and low quality food were found to be significantly different (F_(1,257)=26.92, p<0.001). No significant difference was found between time pre-consumption (F_(1,257)=0.03, p=0.8520). A third test was run to assess if more high quality food or a higher frequency of food regardless of quality affected foraging. This was done by adding high quality food at 30-sec intervals in one area while adding food with a pattern of high quality- low- low- low every 15 seconds to another distinct area. We found that fish responded with higher numbers in the area receiving a higher amount of high quality food (mean=7.60) than the high quality food in the higher frequency test (mean=5.35, t=2.417, df=63, p=00185). However, the high quality food in the high frequency test was consumed faster (mean=0.45 sec) than that of the low frequency test (mean=3.57 sec, t=3.312, df=63, p<0.001). Low quality food was responded to by less fish (mean=4.16) and consumed more slowly (mean= 8.81 sec). Contrary to our prediction, we found that food was both individually tested for quality as well as pursued based on pattern recognition of high quality food. Overall, it can be concluded that B. guatamalensis react to food hitting the surface in a manner of pattern recognition but use quality assessment after food enters their mouth.

Using the Island Biogeography model to determine island characteristics in tropical microhabitats 

Jordan Goetting, Amy Niemela, Tom Langer

Islands in the stream at La Selva

Boulders in streams and fallen logs provide a unique place for tropical plants to grow, making these surfaces important contributors to species diversity. The Equilibrium Model of Island Biogeography (EMIB) is a well-established model that predicts the species richness on islands based on rates of immigration and extinction. These rates are predicted to be affected by the size of an island and its proximity to source populations (the “mainland”). In the rainforest within La Selva Biological Station the boulders and logs are distinct habitats that could act as islands within their greater environment.  By accepting the EMIB as a working model of the forest, we were able to use it as a tool to determine whether or not these two microhabitats could be defined as islands. We hypothesized that species diversity on both fallen logs of a forest floor and boulders within streams would show trends predicted by the EMIB: species diversity should increase with island size and decrease with distance from source populations.  We measured the surface area of ten “islands” and the distance from each island to the nearest island at each of three different sites per microhabitat. We also measured the number of plant species on each island. As predicted, there was a significant positive correlation between island size and species diversity for both microhabitats (fallen logs: R² = 0.4643 p<0.0001, boulders: R² = 0.4041 p=0.0003). However, we found that there was no significant relationship between species diversity and distance from other islands for either microhabitat (fallen logs: R²=0.0611 p=0.1879, boulders: R²=0.0440 p=0.2840). Therefore these microhabitats follow the EMIB based on the island size but not on connectedness. This implies that colonizers are not coming from the nearest island that we measured distance to, but rather they are coming from an alternate “mainland” source. We conclude that boulders and logs within a tropical ecosystem function as ‘islands’ in certain ways to increase species diversity. This is important to take into account when clearing forests or damming streams.

Tadpoles with a side of fava beans: Cannibalistic behavior of Bufo marinus tadpoles at the La Selva Biological Station, Costa Rica

Cory Birkestrand, Liz Chambers, Braedon Wieseler, Matt Scott

The prevalence of cannibalism in wild populations of aquatic animals is often underestimated. Cannibalism may be advantageous due to the nutritional benefit of consuming animal tissue, especially where food is scarce or less nutritious. A potential consequence for cannibalistic behavior is the potential disease transmission from the deceased organism to the consumer. However, there are costs associated with cannibalism due to the challenge of fighting an equal and the potential for disease transmission from a conspecific carcass. Here, we study behavior associated with cannibalism in tadpoles of the cane toad Bufo marinus. We studied an aggregation of tadpoles on the banks of the Rio Sarapiqui in La Selva Biological Station (watch their cool movements here). Rapid changes in the level of the river caused some of the tadpoles to become trapped within small tide pools that eventually lead to their death. After the water rose, the surviving tadpoles would consume carcasses of the dead B. marinus tadpoles. Here we tested whether the tadpoles were more reluctant to consume a tadpole carcass or the pulp of Passiflora fruit from a nearby tree. We conducted feeding trials in low (<50 tadpoles/m₂), medium (50-250 tadpoles/m²), and high (>250 tadpoles/m²) density areas in natural habitat. We measured initial discovery time (the time it took for the first tadpole to begin feeding on an item) and the difference in time between the fourth discovery and fifth discovery (= “5^th discovery time”). We predicted that tadpoles would initially take longer to begin feeding on a carcass but subsequent discovery would be faster for carcass feeders due to the potential costs associated with feeding on a conspecific. We found that, at all densities, tadpoles discovered fruit faster than carcasses (p<0.0001). However, the difference between the length of the 5^th discovery time and that of the initial discovery time was much larger from carcasses than for fruit. These results suggest that tadpoles were more reluctant to feed on carcasses than on fruit, but once carcasses were fed upon by one tadpole reluctance in other tadpoles disappeared. In an isolated pool, we tested (video) whether tadpoles would become acclimated to cannibalistic feeding by examining whether discovery time would decrease on successive feeding trials. Our results showed that feeding on the carcass occurred more readily after previous exposure, suggesting that tadpoles that have previously taken part in cannibalistic activities are more likely to feed readily on a carcass in the future. Together, our results suggest that B. marinus tadpoles respond to the costs and benefits associated with cannibalism.

{Editor’s note: This semester, UST senior Nick Michalak is doing an independent study in which he is reading and writing about prominent books in Biology that are written for a general audience (the “lay public”). Here is the first of his entries.]

Nick getting some inspiration

I’m mingling at a New Year’s party this past December, when the host calls me over to chime in on a discussion her fiancé and his friend are having. I bounce over, we exchange niceties, and the fiancé’s friend confidently states, “Psychology is a soft science.” He’s a chemical engineer, proud of his role as a “hard” scientist, and he goes on to say that, “You can ask a chemist to make a certain amount of a specific compound, and he can cook up almost exactly that amount. Psychology just doesn’t have that kind of predictive power.”

I’ll spare you the details of our mostly half-baked exchanges. I do, however, want to highlight this notion of predictive power in science. Yes, a pharmaceutical engineer can take raw materials and tell you almost exactly how many kilograms of a medicinal compound he can make. A behavioral scientist can only approximate how many people will purchase that compound, and actually take it. You can say the same about the guy behind the Subway counter making sandwiches, and the party planner pondering how many people to order for. In the scientists’ case, to say that the engineer’s prediction of yield is more accurate than the behavioral scientist’s prediction of the target group’s consumption isn’t wrong, but I think the distinction is redundant. It’s redundant because these scientists are answering different questions. Electrical currents, organic compounds, vaccines, car engines, and bridges behave more predictably than do critters and people. Or maybe animal behavior is just as predictable, but the large variance in individual differences (e.g., personalities, physical traits) and features of specific environments (e.g., food sources, mating opportunities) make the task a little messier. When push comes to shove, this predictive power that people like to underscore in the old and tiresome hard science/soft science dichotomy is actually confined within the parameters of different scientific disciplines; these parameters are set by the questions these disciplines tend to answer best.

My interest in this topic was reignited when I began reading Robert Sapolsky’s book, The Trouble with Testosterone: and Other Essays on the Biology of the Human Predicament¹. In his introduction, Sapolsky, a neurobiologist at Stanford, explains that behavioral biologists are trying to understand bad behaviors by exploring connections between the body and the mind. Is anti-social behavior the result of differences in neuroanatomy, hormones, genetic abnormalities, drugs, or even junk food? Or are bad behaviors simply the result of bad people? Are diagnoses like depression or attention deficit disorder just euphemisms for sulking and “being a kid”, or are there underlying chemical imbalances and connections within the brain that are producing debilitating differences in thought, emotion, attention, and the like? If the mind is the product of our bodies and our brains (it is), then questions about people, about individualities, generalities, limits, and potentials, ought to be within the scope of not just behavioral scientists, but also natural scientists.

This common ground isn’t just easy to miss; it’s a little unsettling. Sapolsky nails it on the head when he says, “It’s easier to determine how birds navigate while migrating or how muscle fibers contract than to answer a question like ‘Is there a genetic basis to criminality?’” Chemistry, biology, and physics seem so controlled, so distant until we begin talking about them in relation to behavior. Biology is over there, but behavior…no, that’s over here. Don’t challenge our sense of autonomy with your lab coat sciences. Of course, there’s no denying the vast complexity in how people behave in comparison to how body parts work. There are just so many more variables. This is why we’ve known about the structure and circulation of the heart since the 18^th century, but we still have to question whether macroeconomists can help us prepare for a financial meltdown within a practical timeframe. But, as I’ve mentioned, these facts can be used to make silly distinctions. An anatomist or a cardiologist knows more about hearts than an economist knows about the consequences of binning the Euro in Greece. So what? The cardiologist can’t answer the economist’s problems any better, certainly not with the latest literature on heart malformations or gene therapy.

I’m not exactly sure of how a heart specialist and an economist can team up (pulmonary-economics?), but I do know that different disciplines within science offer tools that can be used to tackle complex human behavioral questions. Sapolsky’s book is a compilation of essays illuminating how biologists attempt to answer some of these questions. His goal is to bring good science to the general reader because, “When science works right, it is an amazing thing to behold—it provides us with some of the most elegant, stimulating puzzles that life has to offer. It throws some of the most provocative ideas into our arenas of moral debate. And occasionally, it even improves our lives.” I’ll continue to blog about the topics he addresses with this appreciation for science in mind, and it’s my hope that at the very least, your evaluations aren’t muddied with the idea that science deals only with exact, “hard” answers. Science deals with questions. Let’s see how biology deals with questions about behavior.

1. Sapolsky, R. M. (1997). The Trouble with Testosterone: and Other Essays on the Biology of the Human Predicament. New York: Simon & Schuster.

Maurine Neiman, formerly a post doc in our department and now an assistant professor in the Biology Department at the University of Iowa, recently had her research featured in a Huffington Post article about mating. You can check it out here: http://www.huffingtonpost.com/carin-bondar/no-eggs-no-problem_b_1250895.html

Beef and conservation in a tropical dry forest – notes from Palo Verde National Park

Entering the Palo Verde forest

A main reason that the Introduction to Field Ecology course comes to Costa Rica is so that we can use the rich biodiversity zones as natural laboratories for student-led research projects. Although there is a lot of biodiversity at individual sites, it is amazing how different the flora and fauna can be among the various sites. So far, we’ve traveled from a high elevation, oak-dominated forest at Cerro de la Muerte, to a lowland seasonally wet forest on the Pacific coast (Corcovado), to our recently departed dry forest location (Palo Verde). Visiting such different sites in a short period of time can make your head spin, but it has made for a great adventure.

marshlands at Palo Verde

Palo Verde National Park is a 19,000-hectare area in Guanacaste Province in NW Costa Rica. One main feature of the park is the extensive marshlands around the Rio Tempisque. This area provides important breeding grounds for resident bird species and feeding areas for migratory species; the Tempisque also has the highest concentration of American crocodiles in Costa Rica. In addition, the park has some of the best patches of dry forest left in Central America; the relatively open canopy in these forests make it easy to see mammals (we saw agoutis, collared peccaries, coatis, white-tailed deer, and monkeys) and snakes (here is a video of a rainbow boa that we saw).

Maya Peters at "La Roca" - a limestone perch

Tropical dry forests are one of the most vulnerable ecosystems on earth. Tropical dry forests can actually be quite wet – for example, the average rainfall at Palo Verde (150-200cm/year) is about 3 times higher than the average precipitation in Minneapolis. However, a tropical dry forest has an extensive dry season that has a dramatic effect on the biology of the system. The fertile soils and mild climates in these areas make them well-suited for human activity, including logging, agriculture, cattle ranching, and, more recently, tourism. It’s estimated that only 1.7% of the original tropical dry forest cover remains in Central America (Olson et al. 2001).

a 6-ft croc on the Tempisque

Many Costa Ricans moved into the Guanacaste region after the 1930’s to search for fertile land for subsistence farming. However, the main pressure on the forest came from 2 sources directly related to activities in the United States: timber extraction and beef cattle production. Guanacaste was a major source of mahogany, an excellent wood for building because of its workability, durability, and lack of knots. Much of the mahogany in the region was logged before 1960 for shipment to markets in the US. After 1950, much of the forest in Guanacaste was cleared for pasture. The intensity of ranching was fueled in large part by the increase in beef prices that were associated with a massive increase in demand for beef by American consumers. The impact of beef prices on forest clearing wasn’t limited to Guanacaste. This phenomenon, termed the “Hamburger connection”, led to forest clearing throughout Central and South America (Myers 1981).

Dan, our guide Raphael, Braedon, Tyler, and Evan in the marsh

Since the mid-1980’s, forest cover has actually increased significantly in Guanacaste province due to declines in beef prices and changes in socioeconomic patterns (Calvo-Alvarado et al. 2009). Ranching became less profitable in the region because the Costa Rican government withdrew their support for the industry, and because beef consumption in the United States began to decline as consumers became more health conscious. In addition, beach- and eco-tourism have become much more common in Guanacaste, and tourism is now the most important industry in Costa Rica.

the group in a cactus grove

This background provides context for our stay at Palo Verde. The accommodations at our site were simple but more than adequate: cold-water showers, bunk beds with mosquito netting, a classroom that even had air conditioning. We spent the morning and late afternoon hours out in the forest doing research projects on ant lions (Jordan Goetting, Tyler Abrahamson, Matt Scott), the bull-thorn acacia (Leah Ruhland, Maya Peters, Katelyn Bojan, Tom Langer), ant foraging (Mark Painter, Braedon Wieseler, Dan Oseid, Amy Niemala), and dragonfly activity patterns (Evan Nolander, Liz Chambers, Cory Birkestand). The mid-day “unforgivable hours” – when the temperature reached 100F – were spent resting or doing writing and data entry in the classroom. We also found time for an occasional hike to limestone promontories that looked out over the marshlands, a boat ride along the Tempisque, and a surprisingly intense soccer game. No one seemed to mind the fact that our resource use was much lower than it would be back home. Simple was good, and this theme was part of some of our late night conversations about conservation and the earth’s ecology. Given the direct connection between activities of Americans and the pressure on biodiversity preservation in this region, we begin to understand that we can really make a difference. And spending time in this amazing place should help motivate us to help simplify the American lifestyle because we can see first-hand what is being lost.

mark painter and dirty dan oseid setting up their experiment

Calvo-Alvarado J, McLennan B, Sa´nchez-Azofeifa B, Garvin T (2009) Deforestation and forest restoration in Guanacaste, Costa Rica: Putting conservation policies in context. Forest Ecology and Management 258: 931-940.

Myers N, (1981) The hamburger connection: how Central America’s forests became North America’s hamburgers. Ambio 10: 3–8.

Olson DM, et al. (2001) Terrestrial ecoregions of the world: a new map of life on earth. BioScience 51: 933–938.

 

Maya, Leah, and Tom working on the acacia-ant mutualism

Cory, Liz, and Evan observing dragonfly flight behavior

Student-led ecology projects in a remote tropical forest

Lab courses in Biology provide students with training in many aspects of the scientific process, but students rarely have the opportunity to come up with and develop their own research questions. The Introduction to Field Ecology course,  which is organized almost exclusively around student-led projects, is an exception. The course travels to sites in Costa Rica for a month. Students spend a couple of days at each site making observations which they then use to generate a question about the ecology or behavior of organisms at the site. They then develop an experimental design, collect data to test predictions, and present their findings to the group. It is a great opportunity to employ their creativity, inquisitiveness, and effort to the process of discovery.

We recently finished a week-long stay at Corcovado National Park in SW Costa Rica. All of the students did amazing work. Below are abstracts from each of their projects. Videos and pictures from their studies are embedded.

Amy and Leah observing spider monkeys

Relationship between social structure and lifestyle habits in co-existing monkey species in Corcovado National Park

Amy Niemela, Mark Painter, Leah Ruhland, Matt Scott

a capuchin monkey

Much of the world’s biodiversity is in tropical forests. Similar species often coexist in the same location, but the factors that allow for their coexistence are often unclear. Monkey species in Neotropical forests are known to have a variety of distinct behaviors and social organizations.  In some species, the alpha male fills the role of a lookout when the rest of the troop is foraging, while in others, each individual looks out for itself.  Social structure can affect movement patterns through the canopy in a similar way in regards to how mothers caring for young respond to challenges when moving from tree to tree.  To test potential relationships between social organization and foraging or movement habits, we performed an observational study in Corcovado National Park on three coexisting monkey species: spider monkeys (video), howler monkeys, and white-faced capuchins (video).  We measured forager vigilance by comparing the amount of time spent surveying surroundings to the amount of time focused on foraging.  We then compared vigilance among species in both the presence and absence of an alpha male lookout.  We measured movement patterns by counting the number of gaps in the canopy from one tree to another that an individual crossed in the observed time, as well as the number of times that the individual jumped in the same period.  We found that capuchins, howler monkeys, and spider monkeys had significantly different levels of vigilance when foraging.  In addition, individuals foraging in the presence of an alpha male lookout were significantly less vigilant than individuals in troops where the lookout role was not clearly defined.  Capuchin troops never employed a lookout and individuals spent much of their time being vigilant. In contrast, howler monkeys always had an alpha male lookout and individuals were rarely vigilant. Half of observed spider monkey troops had a lookout, and individual vigilance was significantly higher in the absence of a lookout.  In regards to movement patterns, mothers faced a similar number of canopy gap-crossing situations as non-mothers. However, mothers jumped at a significantly lower frequency than non-mothers across all species.  This result suggests that, in any species, the role of caring for young affects risk-taking behavior when traveling through the canopy.  Overall, we conclude that there is a clear relationship between community roles and foraging and movement patterns in these three monkey species.

Size-based differences in territorial displays and activity levels in the common basilisk (Basiliscus basiliscus) in Corcovado National Park

Cory Birkestrand, Katelyn Bojan, Liz Chambers, and Jordan Goetting

Basiliscus basiliscus in Corcovado

Competition for territories containing prime resources is common behavior for many organisms. Some species maintain territories by displaying aggressive behaviors while others must actively search for resources. The common basilisk (Basiliscus basiliscus) is a Neotropical basking lizard found in lowland areas near rivers and streams. Male basilisks are territorial, holding and defending their territories by exhibiting aggressive head bobbing and chasing behaviors. In this study, we examined the relationship between size, distribution, activity level, and territorial display of the common basilisk. We predicted activity levels and territorial displays would be higher in smaller basilisks because small basilisks compete for territory with lizards of all sizes, whereas larger basilisks typically only compete with basilisks of similar size. We conducted 11 30-minute observations over a 3-day period (see videos of Cory here, of Katelyn here, and of a small basilisk here). We classified basilisks by size (small, medium, or large), number of head bobs, and number of dashes for each observed basilisk. We found that small lizards were more active (p<0.0014) and exhibited more territorial displays (p<0.0001) than medium or large lizards. It was also found that small and large basilisks generally occupy distinct areas within each habitat. Our observations suggest that small lizards may have higher activity levels and exhibit more territorial displays because they must move around and compete with basilisks of all sizes for territory and resources, whereas large basilisks have larger, more established territories. Large basilisks only take action to defend their territory when others of the same size challenge them. Also we suggest that small and large lizards occupy distinct areas within their habitat because large basilisks are more dominant, and therefore occupy the most preferable and protected areas, whereas smaller subordinate basilisks are forced to occupy marginal areas of the habitat.

Trade-off Between Safety and Food Acquisition in Terrestrial Hermit Crabs

Maya Peters, Tyler Abrahamson, Braedon Wieseler

Tyler, Braedon, and Maya investigating hermit crab behavior

Animals often face a trade-off between acquiring food and staying in safety. However, the nature of this trade-off may differ among individuals with different characteristics, and it may also differ across environmental conditions. Here, we investigate foraging-safety tradeoffs for terrestrial hermit crabs (Coenibita compressus) (video of crabs eating coconut) at Corcovado National Park, Costa Rica. This species is found across a gradient from exposed beach, to a beach-forest transition zone, to the margins of the forest. We examined whether crab behavior suggests they face a trade-off between acquiring food and defense, and we determined whether the response to this tradeoff depended on crab size and environmental conditions.  We tested defense response by using a stick to mimic a bird attack (birds are major predators of this species), and we compared these responses in the presence and absence of food. Our main results were that larger crabs spent more time in their shell after a simulated predator attack, but only in the absence of food. In addition, crabs without food were particularly slow to emerge from their shell after facing a threat in the forest or on the beach. Because crabs were most abundant at the forest-beach transition zone, our results suggest that predation threat is a major factor determining the distribution of hermit crabs in this environment.

Size and food acting as determinants of interactions in the freshwater shrimp, Macrobrachium americanum

Tom Langer, Evan Nolander, Dan Oseid

The shrimpers doin' some shrimp'n

Why do some organisms exhibit territorial behavior, while others do not? One explanation is because the benefits of being territorial depend on ecological conditions. Macrobrachium americanum is a freshwater shrimp common in lowland tropical rainforests and size-dependent behavioral interactions among juvenile M. americanum can easily be observed in low-flow pools. Based on general observation, we classified juvenile M. americanum into three categories of size, small, medium, and large. Observational and experimental data were collected from eight pools in two streams found in Corcovado National Park and analyzed by viewing densities and numbers of interactions between sizes in the presence and absence of food. Data were analyzed using a two-way ANOVA and Tukey’s HSD test. We found that size of shrimp (F_1,5=21.94, p<0.0001) significantly affected the number of interactions among shrimp; the most common type of interaction was medium-sized shrimp interacting with small shrimp. Interaction frequency also generally increased when we added food to natural pools (F_1,1=18.73, df=1, P<0.0001) In addition, there was also a significant size-by-food interaction (F_1,5=2.77, P=0.0228) because interactions involving medium sized-shrimp became more frequent relative to other interactions in the presence of added foods. Our results suggest costs and benefits of territorial interactions differ among different sized individuals in this population. Future work should determine the ecological factors that account for these differences.

In the land of endangered species – sightings of the Baird’s tapir

Liz's picture of a male tapir on the beach in Corcovado

Our Introduction to Field Ecology course spent last week at Corcovado National Park in SW Costa Rica. This park is the largest protected area of lowland forest on the Pacific coast of Central America. Larger parks can support populations of animals that have large home ranges, special habitat requirements, or are particularly at risk when in proximity to human settlements. Many of these species – jaguars, white-lipped peccaries, and scarlet macaws – are abundant in Corcovado, and they are one of the reasons why this place is such an exciting location to visit.

Braedon's picture of a baby tapir in the Rio Claro

Probably our most exciting animal sighting at Corcovado was the Baird’s tapir, Tapirus bairdii. Baird’s tapir is the largest non-domesticated land mammal in Central America. It used to be abundant across its range from southern Mexico to northern Columbia. However, in 2002 it was listed as Endangered by the International Union for the Conservation of Nature (IUCN), which estimated that there were only about 5000 tapirs left in the wild. This number is down by at least a 50% in the last 30 years, and it’s expected to drop by at least another 50% in the next 30 years.

Tapirs don’t have many natural predators. They’re big animals (about 2m long and 1m high) that are likely only attacked by big cats (jaguars and pumas) and crocodiles. These predators are themselves rare. Instead, the threats to tapirs are related to human activities: habitat loss, hunting, and transference of disease from domestic animals. About 70% of forest land in Central America has been lost in the last 40 years, and much of the remaining forest has been fragmented. Fragmentation is particularly detrimental to tapirs because small fragments are unable to maintain viable tapir populations. Even though tapir hunting is generally illegal across Central America, poaching laws are rarely enforced. Larger parks like Corcovado have guardians, but there are usually far too few park rangers to eliminate poaching. There has been speculation about disease transmission from cattle and horses. It’s probably important, but the magnitude of the threat isn’t yet known.

many of us with our honorary class member, a male tapir

Luckily for us, Corcovado still has a moderate number of tapirs and most of our group has been able to see one. Liz Chambers and Tyler Abrahamson took several pictures of a tapir on the beach. Our group kept their distance (tapirs have been known to charge humans that get too close) but they were still able to get great photos, including a nice group shot with the tapir in the background. In addition, Matt Scott took this amazing video of a male tapir walking near the ocean at low tide, and Tyler Abrahamson took this great video of a tapir in the surf. Tapirs in the surf aren’t looking for food – they eat fruit and leaves in the forest. Tapirs are good swimmers and they like to wade in the ocean or rivers to cool down and to get rid of ticks and other ectoparasites.

Spending time in Corcovado has made us think a lot about whether it’s possible to create a sustainable human society. Can we control resource use and reduce environmental degradation such that our current biodiversity is maintained over the long term? Watching a tapir walk through the surf gives me a sense of urgency; I want to help preserve places like Corcovado so that we can bring our kids and grandkids to see these amazing creatures.       

This January, UST senior Abbie Bruning is conducting research in Panama on how diet affects social immunity in the ant, Ectatomma ruidum. Since January 3rd, she has been on Barro Colorado Island in the Panama canal zone conducting research on her own. Below is a description of her experiences:

Abbie at work in the lab on BCI

A stint on Barro Colorado Island (Panama) in the dry season – by Abbie Bruning

                Coming back to Barro Colorado Island (BCI) has been a fun and exciting experience. I was previously on the island May through July of 2011. The atmosphere of the island is much different this time of year compared to the summer months. This is not only because the number of researchers are significantly reduced but also because, starting mid December, the dry season begins. During the dry season temperatures raise slightly and the humidity drops. The significant characteristic of the dry season is the large reduction of rain fall. During the rainy season there is a 40% to 50% chance of rain everyday which makes it very difficult to stay on schedule with field work. While during the dry season you’re lucky if you get a five minute cloud break from the sun, as my Irish skin can attest. (I am still trying to figure out how I got a sun burn while working under the rainforest canopy all day.) My first few days on BCI, my professor Adam and I collected ant colonies almost every day; it would have been impossible to have done that in the rainy season. (Here is a video of Abbie walking the stairs going into the forest. Here is Abbie going into the forest. She’s not wearing field clothes – this was a quick excursion to a canopy tower)

the "Ambient Soil Lab" on Barro Colorado Island

Because of Adam’s help we were able to get the project off and running before he left to go lay on a beach somewhere in a tropical paradise (or to instruct a field research course in the rough terrain of Costa Rica… same thing). Besides the first two weeks I will be working with the colonies of the ant Ectatomma ruidum in the main lab as well as in a building we call the ambient soil lab, which is located back in the forest. Because I didn’t spend as much time in the lab this past summer I failed to notice that the spider monkeys use the lab clearing as their own person playground and that tarantulas set up camp in the cinder block steps outside the back door.

Though BCI is very quiet this time of year the traditions of the island still persist. One running tradition is the Thursday night Bambi talks. These weekly seminars were started initially for researchers beginning in the field to get their feet wet and receive fed back on their work. It is said that the name comes from the idea, like Bambi, that you need to learn to walk before you run. Researchers from Panama City and Gamboa (the nearest town on the mainland) come to the Island for the weekly seminar; the influx doubles the population of BCI. This talk became rather formal over the years so a second less formal seminar, called the Capybara, was created to take over the role that the Bambi once held.

Abbie at the "big tree" on BCI

Another running tradition is “morning walks with Bert”. Egbert Leigh (Bert) is an evolutionary biologist and a recent retiree of the Smithsonian Tropical Research Institute (STRI). It’s hard to fully capture Bert’s presence and role on the island. Bert has lived on the island for years. His children, who are grown, lived and spent most of their childhoods on BCI. On his morning walks he takes young researchers out hiking and discusses plant species, evolution, and literally anything under the sun. Many times for me, and I assume for some others, it’s a little over my head (ok way over my head) but it is a very fun learning experience. Bert also often invites researchers and interns up to his office for a scotch after dinner. The “office” is up on hill. Inside, there are books and journal articles everywhere, and harpsichord music is often playing in the background. Bert will talk at length about ecology, conservation, academia, politics, world history, religion, you name it. It can be a surreal experience. In fact, the entire experience on BCI, from the weekly seminars to the nightly gatherings on the balcony after a long day in the field, is intellectually engaging.

Reflections on culture and ecology in Costa Rica – by Leah Ruhland and Evan Nolander

Most of our course – Introduction to Field Ecology – in Costa Rica focuses on ecology research projects at various locations across the country. However, on our first day in the capital city, San Jose, we ask students to visit a cultural site and to write about how this aspect of Costa Rican culture has affected or is affected by the natural world. We had many great submissions, but we picked two exceptional posts for the blog. Here they are:

A visit to the Gold Museum – by Leah Ruhland

            While in San José, I walked with a group of my fellow students, along the street called Colón, to the Pre-Columbian Gold Museum. While at the museum, I learned a lot about how the presence and use of gold shaped the history of Costa Rica and the culture of its people. I was able to learn about how the trajectory of gold mastery and usage affected the relationship between the nature of the country and the lifestyle of the indigenous people.

The indigenous people of Costa Rica saw gold as a precious item that was to be used for rituals and ceremonies. One specific ceremony in which the use of gold was highlighted was in funerals. One funeral rite known as “ceremonial killing” was a key part of the burial process. In this ritual, an item of gold, stone, or ceramic was intentionally broken or pierced. This was done to completely disfigure the object being used and symbolized the disfigurement of the deceased on earth since they were no longer existing in the same physical form. Gold was incorporated into the trade practices of the natives with other villages to purchase a variety of needed goods such as food, clothing, wood, and pottery.

Artifacts at the Gold Museum in San Jose

The abundance of nature all around the indigenous peoples in Costa Rica made it natural for them to pull this inspiration into their gold creations. The diversity of natural features allowed for the ability to create many different diverse designs, many of which were dependent on the local area in which the person was living. An example of this is of the people who lived on the coasts drew inspiration from marine life and animals such as frogs and fish. All the natives incorporated a lot of natural features such as mammals, plants, people, insects, birds, amphibians, and other organisms into their designs. Another aspect unique to the Costa Rican culture was their tendency to integrate human and animal features in their final gold designs. The creation of disks, diadems, and pendants were also popular designs that were made.

In 1502, the Spaniards reached the Caribbean coast of Costa Rica. The exchange of Old World objects and native gold pieces occurred between the Costa Rican people and these new arrivals. These trades would change the future of the native people who had lived there for thousands of years. The further conquest of the Costa Rican land shattered the lifestyles both politically and socially of the indigenous people permanently. Because of this colonization, the artisan traditions that had made progress over the many years of development were no longer needed to produce the gold objects for the purposes of before and the gold craftsmanship of these people ended up dying out.

The main technique used to extract gold by both the native and the Spanish conquerors were set up in a similar manner. In order to extract gold from the beds and banks of rivers, a terrace was built to be used. Sand that was stirred from the river bottom comes to rest at this terrace. The current of the water is used to separate the lighter materials from those that are heavier, like gold, which are deposited at the bottom. Then this material was washed in a large, porous tray with circular movements until the desired gold product began to appear. This technique is still effective for small-scale extraction today. Some clearing of forests and land area is required to set up these systems. In the future, gold mines would be set up, and excavating on a large scale would cause the tearing down of large areas in order to collect larger reserves of gold for profit.

The natural world of Costa Rica influenced the way the native people viewed and used gold in many different ways. One main connection that the natives had with nature was in how the objects they depicted in gold were of natural items that they experienced in their daily lives and found inspirational. They saw nature as a gift to be protected and admired and showed these feelings in honoring nature in their gold creations. The natives of Costa Rica understood that the earth provided them with all the necessities in their lives. They respected this relationship by using their resources sparingly and only when needed. This included how they viewed and used gold since they didn’t believe that it should be exploited or used in excess.

Importantly, the arrival of the Spanish in the 1500’s had a significant impact on the natural world in Costa Rica. Spaniards changed the original use of gold and other resources that they saw to be valuable when they arrived and conquered indigenous people in this area. They exploited gold as a commodity that needed to be used exclusively for profit. If gold, or any other objects that were valuable, were not collected in as large of quantities as possible, then they considered these objects to be going to waste. They cleared out many different areas and trees to build terraces to be used for small-scale extractions in search of gold to be sold in Europe for profit.

Exploitation of the natural world by humans has been around since the beginning of time. With the continued movement towards modernization in our world, the human population is constantly acting in ways that hurt and destroy our environment without a second thought. Thankfully, research is revealing evidence that we cannot continue acting in such selfish ways if we wish to continue to survive. Continued awareness and movements towards a more eco-friendly way of life are still necessary, however, if we hope to have any chance in saving the world in which we live.

 A change in perspective – by Evan Nolander

On my second day in Costa Rica, I journeyed into the city center in search of the defining characteristic of the Costa Rican people, a characteristic that really separated them from everyone else. I spent time in parks, restaurants, shops and the streets discovering that rather than the differences between societies being what struck me, it was all of the similarities. I saw mothers walking hand in hand with their children and scolding them for wandering too far, elderly couples slowly meandering down the street, men and women in suits bustling from their place of business to their cars or buses, hot pink haired teenagers with piercings through every conceivable section of their face, and in the end, I realized that I could have easily been standing in St. Paul. McDonalds was on this corner, KFC on that, both bustling. Throughout this, I found myself becoming a bit depressed and downtrodden at what I believed would be an incredible, indigenous experience had really just turned out to be a continuation of commercialized society.

Sculpture with nature images in San Jose

However, as I continued through the city I ended up at the Jade Museum of Costa Rica, where the history of the natives was traced from the early hunter-gatherer nomads who settled in an area that was once 98% forest and created the country seen today. Though it wasn’t a modern experience in the parks, streets or restaurants of San Jose, it provided me with an incredible view of the beginning of Costa Rican society and began to show me that, below the surface, there is a truly unique, proud history and feel to the Costa Rican people. The museum provided information on the most basic beginnings of the settlement of the early Costa Rican natives and thus exploitation of land by humans. In order to settle in one place, agriculture and communities were necessary. In order for this to proceed, land needed to be cleared and animals needed to be hunted. However, a unique angle was provided by the Jade museum that took this desire for progress and allowed it to be seen instead as a desire for the acquisition of power. Though jade wasn’t mined in Costa Rica, it was acquired through the trading of goods taken from the land. This jade was used to make headdresses and jewelry for the prominent people within each chiefdom, like powerful families, caciques and shaman. It was in this exploitation of land that the very first example of materialism arose, and personal power took precedence over the health and survival of natural resources. This realization, combined with the commercialization I had seen on the streets of San Jose, initially left me believing that this pattern had continued until today and was the cause for my earlier feelings of disappointment. However, this changed as I began to look and learn more about the prides of the people.

In every establishment, and in almost every public park or display, a theme of nature began to emerge. Rather than the normal run of the mill artwork that is used to decorate cities and establishments, almost everywhere was a depiction of a native plant or animal of Costa Rica. As this realization hit me and I began to think more, I realized that rather than people continuing to care about nothing but power and themselves, at a certain point the people of Costa Rica must have realized that many of the things that identified them were quickly disappearing, something that unfortunately may not be happening in many other places in this world. This realization has created a people who put into motion programs to save their forests from massive amounts of agriculture, and a people who took great pride in displaying what it was that made their country unique at the most basic, ecological levels. This belief was only driven home more when we had the incredible opportunity of visiting a biological research station at Cerro del Muerte, a national park area that had been saved in the same fashion as numerous others in Costa Rica. It was here that I saw Costa Rican pride had flourished in the most pure and inspirational way.

Don Carlos - our host at Cerro de la Muerte

In Cerro del Muerte we had the opportunity to see a group of people that took the greatest pride in living in equal balance with nature and humanity, not tipping to either extreme. Rather than staunch conservatism where humanity is suffocated for the sake of nature, or reckless treatment of the environment where all our resources are destroyed through ignorance and selfishness, a group of people had found a way to build a reserve that was self-sufficient. The area contains a completely self-contained, organic trout farm that runs off water from numerous streams in the area, so as to not deplete one stream too much. The water from the trout farm runs through a hydroelectric generator that powers the homes within the reserve. The trout are fed with worms, which are grown in the organic waste that comes from the humans, cows and horses that live on the land. Some trout are sold, and with it the goods that can’t be grown are bought. Buildings are built from trees in the area, and new trees are planted every year. Seeing this with my own two eyes provided me with a real understanding at how simply, but effectively these people have made an effort to find a way to thrive while allowing the natural ecology around them to thrive. Though it’s only been a short period of time, I feel that I’ll be able to really appreciate the ecological and cultural aspects of the other parks we’ll be visiting in the next three weeks.

From the overlook at Cerro, with Mark Painter, Danny Oseid, Tony Lewno, Maya Peters, Leah Ruhland, Evan Nolander, Matt Scott, Tyler Abrahamson, and Katelyn Bojan

Walking to the “most biologically intense place on earth”

Corcovado National Park in southwestern Costa Rica is an amazing place to visit. It is one of the last large expanse of lowland tropical rainforest in Central America. Lowland rainforest is particularly important for conservation because much of the biodiversity in the tropics is located there. Unfortunately, lowland rainforest contains valuable tree species for logging, and it’s relatively easy to convert into agricultural land. Forest conversion not only destroys natural habitat, but the resulting habitat fragmentation makes it difficult to maintain viable populations of organisms with large ranges. Corcovado, with 263 square miles of continuous forest, is the largest primary tropical forest on the American Pacific coastline, and it is home to populations of some of the rarest animals in the New World tropics – Jaguars, Baird’s tapir, harpy eagles, scarlet macaws, white-lipped peccaries, and the Central American squirrel monkey.

Our class – Introduction to Field Ecology – is currently staying for a week at the Sirena ranger station in Corcovado. Getting here is not easy. One option is a 15-min flight from Porto Jimenez on a small plane. Two of our students, Braedon Wieseler and Amy Niemela, volunteered to fly in with all of our equipment. They saw the pristine forest from above, and bravely endured the landing on the little airstrip cut out of the forest near the station.

the King vulture, Sarcoramphus papa

The rest of the class made it to Sirena by traveling across the Osa Peninsula from the little town of La Palma. We traveled the first 10 km in an old military vehicle; most of the habitat was subsistence farms (banana and oil palm) and river beds. One of the highlights was seeing the rare King Vulture perched on a branch overlooking a dead horse in the riverbed. Another highlight was seeing pairs of scarlet macaws flying in unison above us.

the riverbed on the way to Corcovado

The second part of the excursion was a 23km walk through the forest. Walking 23km through pristine rainforest is the type of experience that one never forgets. Check out some video here and here. Sure, it was hot and humid, and the blisters are still healing, but the sight of huge palm fronds, giant strangler figs, the occasional spider monkey group, and all of the other biological complexity was enough to keep our spirits high throughout. It took us about 7 hours, and was the most demanding hike some folks had ever taken.We knew we were close to the station when we started hearing the crashing waves of the Pacific.

a giant strangler fig at Sirena

Evan Nolander in a contemplative (RSC) moment

a break during the walk to Sirena for Katelyn Bojan, Leah Ruhland, and Maya Peters

Emerging from the forest at the Sirena station was exhilarating. There are a few tourists here (that come by plane, boat, or an equally long hike along the beach), and a small staff. All of the supplies for the station are transported in by boat or plane. The station has photovoltaic cells for generating some electricity, but power is only available here for about 3 hours in the evening. There is a kitchen that makes us 3 hardy meals each day, but there are no other supplies available. Our group is in bed by 9:30 and up at 6, unless someone takes a morning hike at 4 (the pristine beach is a popular location). Everyone is excited about being here and they are developing interesting research projects. We’ll report on those in the near future.

Field Ecology in Costa Rica – A Visit to the Mountain of Death

This January, 14 UST students and 2 instructors are taking part in a field ecology course in Costa Rica. We’re going to visit a variety of forests and ecosystems, ranging from classic lowland tropical rain forest to the endangered tropical dry forests to misty, montane cloud forests. The focus of the course is teaching students how to conduct field-based ecological research. Costa Rica is a great environment for teaching field ecology because there is so much biological complexity. In this environment, students can come up with their own research questions and carry out simple observations or experiments to address them. It’s exciting for everyone when someone is able to discover something new about the biological world using simple tools, ingenuity, and the scientific method.

Our first stop was the capital city, San Jose. Students worked on a statistics assignment on the patio of our hotel. It was a tough assignment, but working on it with a view of the mountains in the background sure beat a sterile classroom in frosty St. Paul.

Cory Birkestand, Mark Painter, Matt Scott - Stats in San Jose

Our next stop was Cerro de la Muerte (Mountain of Death), a high elevation site about 3 hours SE of San Jose.  Cerro de la Muerte is in the Talamanca range, which extends from eastern Costa Rica into western Panama. According to Wikipedia, the name comes from the fact that, in the past, crossing the mountains from the central valley meant a three or four day journey and many ill-prepared travelers succumbed to the cold and rain. Well, it’s certainly misty and chilly but we’ll take care of each other so that no one will succumb to the elements while we’re here!

epiphytes everywhere at cerro de la muerte

Cerro contains many endemic species and interesting habitats. Many of the trees are covered in epiphytes – plants that grow on other plants. It’s so wet that there are sometimes epiphytes growing on epiphytes! Risk of UV damage is high because of the thin atmosphere at this elevation, and many plants have adaptations for dealing with UV stress. One thing that seems odd about this habitat is that there are close relatives of temperate species. For example, there are a lot of oak and alder trees, and the bird fauna include robins, finches, thrushes, wrens, and juncos. One place we’re excited about seeing is the paramo, which has stunted shrubs, dwarf bamboo, and tree ferns, and smaller plants like blueberry, gooseberry and lady’s slipper.

the field station at cerro de la muerte

Our field station at Cerro is a trout farm that aims to have minimal ecological impact. It’s an amazing place. One of the owners, Carlos, has raised trout on the land for over 20 years and has built much of the infrastructure. The trout farm is impressive. There are a series of tanks and ponds that are used to provide fish at different life stages with the conditions they need to thrive. The fish are fed a variety of food, including worms from compost supplied with on-site kitchen waste. Matt Scott made a cool video of the trout – it’s here. Carlos explained that his trout farming operation is completely organic, and that he has developed and optimized his own organic techniques over the last 20+ years.

There are a lot of admirable qualities about this place. Much of the electricity for the station comes from a turbine that is powered by a stream on the property (Evan Nolander explains the process here). The buildings and furniture are constructed primarily with oak and alder that has been harvested locally. Almost all of the food comes from local sources. Carlos emphasized that the most important thing to keep in mind when living here at this station is maintaining balance. For example, whenever any trees are cut down and used for building material, he makes sure to plant more seedlings in order to ensure that the forest’s diversity is preserved. He proudly demonstrated this by showing us trees he planted 25 years ago that are now flourishing in the forest, as well as seedlings of the endangered palm tree that he plans to plant in this area to ensure the survival of this species. Being here gives you a sense that it’s actually possible for humans to live sustainably. And so far, the simplicity of the life seems to suit us well.

Student research in Panama – the beginning of an adventure

Today UST senior Abbie Bruning and I are traveling to Barro Colorado Island (BCI) in Panama to start a research project

Abbie with friend

on social immunity in ants. Abbie is going to be on BCI through January and will write several entries about her experiences. Today we wanted to write a quick entry describing a bit about our travels, with some information about Panama and the history of BCI thrown in.

Panama has been undergoing an economic boom over the last few years and signs of modernization are everywhere. The skyline of Panama City looks like Miami – glossy new skyscrapers pressed right up against the beach. But it’s really stressful in Panama City. It’s very noisy – drivers honk constantly (what are they honking for?) – and filled with smog. Crossing a street is treacherous – you just have to go for it. Luckily, there are some cool out-of-the way hostels that give some respite. A fun place to go is Luna’s Castle in the old part of the city (Casco Viejo), which still has a lot of old french colonial architecture – some it well-maintained, some of it crumbling.

the crumbling charm of casco viejo

We were able  to bypass Panama City on this trip, as we left St. Paul early and are able to make it all the way to BCI in one day. From the airport, we took a 1-hour taxi ride to the town of Gamboa, which is in the Panama Canal Zone. In Gamboa, we sit on the docks for an hour or so watching huge tankers travel through the canal (a video of Abbie’s description of the trip is here). We then take a 45 minute ride up the canal in a “water taxi” (video).

Barro Colorado Island was formed in about 1913 after the damming of the Chagres River. The damming of the river was a key step in creating the Panama Canal. The original attempt to create a canal in Panama was led by the indefatigable Ferdinand de Lesseps, who had also overseen the successful completion of the Suez Canal. De Lesseps, with the backing of the French government, insisted on building a canal at sea level. A main impediment to the construction was that the rainy season would turn the Chagres into an unstoppable force that would wipe out much of the progress made during the dry season. The French effort was abandoned in 1890 after numerous setbacks, deaths due to diseases such as yellow fever and malaria, and financial mismanagement. The United States picked up the effort in 1904 and began building a lock-style canal. The Gatun Dam of the Chagres was built between 1907 and 1913. It created the Gatun Lake at 85-ft above sea level. Locks lift ships up to the level of Gatun Lake, and then much of the transit across the Panama isthmus occurs across the lake instead of a traditional canal. A great history of the Panama canal is “The Path Between the Seas” by David McCullough. BCI is a 1500 hectare former hilltop that is now in the center of the canal zone.

BCI was set aside as a nature preserve in 1923. The only permanent structures that have been on the island since its formation are buildings associated with a field station run by the Smithsonian. The station is probably the most famous field station in the New World – much of what we know about the biology of the new world tropics is because of research that has been done at this site. This station is where Abbie is going to stay for the next month. (see the cool video of us arriving at BCI here). Almost all of the island is made up of pristine forest, filled with white-faced and howler monkeys, ocelots, and three-toed sloths. Abbie will be able to spend her days walking through the hilly terrain listening to the sounds of the forest (while thinking about ants). There are very few people here at this time of year, so Abbie will be spending much of her time alone. Luckily there is a staff that will provide her with three buffet-style meals each day. These comforts allow her to focus on the work and the experience of life in a tropical rainforest. Let’s hope she comes back and doesn’t end up like Mr. Kurtz in Joseph Conrad’s Heart of Darkness.

Abbie by February?

I am not a fathead

I remember an episode one summer day when I was a teenager. I was daydreaming while I was riding my bike and I rode through a stop sign into an intersection. There was a car at the stop sign on the cross street and a tough-looking guy was watching me while leaning out his open window. He had started pulling out into the intersection and I almost hit him. As I clumsily tried to stop, the only thing he said was “fathead”. And then he drove off.

Well, I do have a big head. But all humans do. Brain mass:body mass ratio is higher in humans than in most other mammals (although it’s certainly not highest in humans – see comment below) ; it’s about 3 times larger than is the ratio for our closest living relative, chimpanzees. So, instead of “fathead”, “encephalized” is a more appropriate description of my appearance.

Why are we humans “encephalized”? Brains are costly to maintain, so animals with larger brains must either have higher overall metabolic costs or have reduced maintenance for other metabolically active tissue. This latter idea has been called the “expensive tissue hypothesis”. It proposes that mammals decrease investment in expensive tissues (like the gut) to fund relatively large brains. This is a classic example of a tradeoff – using more resources for cologne means less money for dinner on your date.

In the most recent issue of the journal Nature, Navarette and colleagues tested the expensive tissue hypothesis using data from 100 mammal species. They found no evidence that mammals with larger brains had relatively smaller guts or that any other major organ was smaller. So much for the expensive tissue hypothesis.

Navarette and colleagues did find evidence for one tradeoff: mammals with larger brains have less body fat. Fat stores aren’t expensive to maintain, but carrying them around might make it harder to avoid getting eaten – luckily for us there aren’t tigers roaming the mall. The authors suggested this fat-brain tradeoff reflected alternative starvation resistance strategies: fat stores offer a “physiological buffer” against starvation, and big brains offer a “cognitive buffer”. In other words, you don’t need to pack on the fat if you’re smart enough to figure out how to get food when times are tough. This tradeoff doesn’t seem to exist in primates. For example, we big-brained humans also carry a lot of fat (14-26%) compared to chimpanzees (3-10% body mass). Navarette and colleagues suggest our efficient form of locomotion – bipedalism – may allow us to be both fat and “encephalized”. Go humans.

So, I’m not “fatheaded”. I’m encephalized and this provides me with a cognitive buffer against starvation resistance. I wish I could have said that before that guy drove off.

Perspective of an Undergraduate – Attending the ESA meeting in RENO 

(This is a guest post by Katie Miller, a senior Biology major)

Although intimidating as it might be for an undergraduate student to hop a plane to a new place they haven’t been before, possibly by themselves, and attend a big scientific meeting, I believe that it can be an extremely enriching experience. Recently, I temporarily vacated my undergraduate classes to attend the Entomological Society of America meeting in Reno, Nevada. For those who don’t know, this is the largest insect meeting in the world where scientists from almost every continent attend to present their research and attend professional networking and collaborative meetings. Upon the looming date of departure to the meeting, certain troubling thoughts occurred to me such as: “what if I don’t see anyone I know?”, “what if I mess up my presentation?”, and “what about my coursework!” Despite the potential hazards of attending a scientific meeting during the semester, there are numerous benefits that an undergraduate student can gain from attendance. During the meeting, I had a variety of different opportunities to learn about hot topics in Entomology and Ecology and about research related to my current project on ants.

One talk I attended was by Ben Hoffmann from Commonwealth Scientific and Industrial Research Organisation (CSIRO) in Australia on “Invasive ant eradication – history, global status and requirements for improvement”. Biological invasions can have devastating impacts on ecosystem function and are one of the main threats to biodiversity globally. Successful eradications are rare. For ant species, there are only ten recorded cases of successful eradication of an invasive ant even though eradication efforts have been going on for nearly a century¹.

invasive fire ants attacking a chick on the Galapagos islands

No doubt the increase in global commerce is a major factor behind the increase in ant invasions, requiring even greater management actions. It certainly doesn’t help that there are folks out there attempting to actually sell invasive ant species (http://myrmecos.net/2011/11/19/world-of-ants-store-sells-extreme-pest-insects/)! Hoffmann discussed the fact that most eradication programs begin well after populations have been established, making success much less likely. There is also a lack of understanding of how ants process food within a nest, making effective food baits more difficult to develop. Furthermore, there are underdeveloped links between researchers and rangers/managers (at least in Australia…not sure about the U.S. but I wouldn’t be surprised if there are similar problems in the U.S.). Managers are not necessarily required to publicly communicate strategies or results of their program and as a result there is a lack of publication of project outcomes. I am deeply concerned about the ever increasing species extinctions and subsequent decreases in biodiversity occurring as a result of human impacts and thus I find it particularly important that people become aware of issues such as the problems Hoffmann highlighted in his talk.

Another talk I went to by Cleo Bertelsmeier, which focused on a database website called Ant Profiler (http://www.antprofiler.org/) set up to record ecological characteristics of ants including morphology, behavior, habitat, nesting, distribution, and invasiveness status. Once information is loaded into the system for a given species of ant, the ant is given a sort of ID card which lists all of its traits. This database has the potential for use to make comparisons among a variety of ecologically important traits, and to examine trait variation across geographic distributions (it could therefore be useful in assessing the spread of invasive ant species). One might worry that simply checking off check boxes next to certain traits could potentially delimit the value of comparison of characteristics due to ambiguous definitions of the particular traits used in the database. For example, Ant Profiler lists tree/canopy, leaf litter, ground, twigs and logs, underground, nomad, and ubiquitous as possible nesting types for ants. However, some ant species such as certain Myrmica ants have been found to nest in snail shells and this does not fit nicely into any of these categories. However, the database could still serve as an important research tool and possibly be used to identify areas where ambiguous definitions might hinder analysis of trait distributions. Furthermore, research on other organisms could stand to gain much from a database such as this one, where multiple characteristics of the organism and natural history are all recorded in one place in a digestible format. This database is clearly just in its beginning stages and needs a lot of work before it can become a valuable research tool but one can hope that with time the site will be able to gain enough contributors to make the site viable.

There were also a number of interesting talks that weren’t about ants. For instance, May Berenbaum, a professor and head of the Department of Entomology at the University of Illinois at Urbana-Champaign (UI) gave a talk about “What students learn through engagement in entomological entertainment-related activities”. Her talk focused on the Insect Fear Film Festival held at UI since 1984. During this festival, they show two or three feature-length films such as the films “Them” and “Invasion of the Bee Girls” interspersed with animated shorts, each focusing on a different theme. As May puts it in her summary of the history of the festival “When we began, Ronald Reagan was in office, materialism was rampant, and insect movies were terrible; today, there’s a democratic president in Washington, environmental awareness and volunteerism are more fashionable, and insect movies are still terrible; it’s nice to know that there are some things in life to count on”. The festival is also interspersed with opportunities for the public to see and handle live specimens, enjoy deep-fried appetizers, get the insect fear film festival annual T-shirt (which has gained fame by itself), and get more accurate answers to questions about insects than what’s depicted in the films. Students are heavily involved in this festival and as a result have a number of opportunities to engage with not just the university community but the general public as well. My favorite example she gave occurred at the 1999 mosquito film festival where students organized the thematically relevant blood-drive. It has always been my constant struggle to convince certain members of my family of the importance of insects and that we need not always just squish them because it’s somehow politically correct to hate them. Her presentation and other outreach related talks I attended gave me many new ideas for current efforts I am pursuing on my campus and more fuel to continue my attempt at changing these views or at least with multiple new ideas to “brain wash” my baby sister…

Through talks such as these, I had multiple opportunities to speak with distinguished scientists, even though I had never met some of them before. This opportunity to speak with experienced professors and current graduate students not only allowed me to expand my entomological and ecological knowledge but to obtain some great advice on dealing with the hazards of research, the process of moving forward toward getting a PhD, where good potential future labs are that I might want to join to obtain my PhD, and, well, good advice on how to live life as a responsible citizen. Even if the undergraduate student does not wish to go on to graduate school, much can still be gained from attendance and I left the meeting inspired and ready to take action.

¹Hoffmann, B. (2011) Biodiversity and Conservation 20:3267-3278.

 Introducing the Real Green Man

Humanity currently faces significant environmental challenges due to climate change, habitat destruction, overexploitation of natural resources, and biodiversity loss. These challenges are related to human population size, resource use, and waste production. Given that our population continues to grow and our per capita ecological footprint gets ever larger, there’s a lot of work for us to do. Is there any chance that we can make our society sustainable? Can we create a world in which we live happy lives in a vibrant society without degrading our natural systems? The short answer is YES: good descriptions of the policies that we need to enact can be found in recent books by Thomas Friedman and Paul Gilding. But we need passionate buy-in to create major societal restructuring needed to become sustainable. We need a war effort focused on reducing our environmental impact.

our future?

So how do we increase our collective appreciation of these dire circumstances? One way would be to target the message to demographics that show the least concern. If we can begin a dialogue with the most skeptical among us, than it should be easier to build a broad consensus that will actually lead to action.

So what’s a demographic to target? What is a group that shows less concern about environmental issues and can be easily targeted with “educational information”?

The most obvious answer is MEN. A Gallup poll of Americans from 2006 assessed feelings about environmentalism; it found that 68% of woman were either “sympathetic to or active in the environmental movement”, while only 56% of men were. But does it have to be this way? Are the goals of environmentalism in conflict with the goals of the average man? Maybe we just need to find some common ground.

And I think there is a lot of common ground. There are clearly aspects of the stereotypical male lifestyle that can help galvanize environmentalism. So here’s a first attempt to put together a list of the traits for what I’m calling “Real Green Men”. I’m sure this list is incomplete and I’d love to get some more suggestions. But here’s what I came up with:

1. Real Green Men don’t “shop ‘til they drop”. Social pressures sometimes force a real man to spend a lot at the mall. Women report enjoying shopping more so than men and are more involved in shopping activities (Fischer & Arnold, 1990, Journal of Consumer Research, 17, 333-344). For example, 78% of respondents to a survey about Christmas shopping (Laroche et al. 2000, Canadian Journal of Administrative Sciences, 17, 1-19) and 73% of respondents to a survey about food shopping were female (International Mass Retail Association, 1993). If pressured to go shopping or to allocate resources to shopping, a Real Green Man can say “the United States emits more greenhouse gases than any other country except China, and we emit more than 4 times the amount of greenhouse gases per capita than do the Chinese. Consumerism in the US is a big contributor to these emissions. And we’re in trouble – in 2010, the amount of greenhouse gases emitted globally exceeded the International Panel on Climate Change’s worst case scenario model. The mall is not a place for a Real Green Man or his kin.”
2. Real Green Men don’t obsess about their appearance. Social pressures sometimes force real men to wear clean, wrinkle-free outfits. Social pressures force real men to take daily showers and shave. A Real Green Man can stand up to those pressures. He can say “more than one out of six people on the planet lack access to safe drinking water, and more than one out of three lack adequate sanitation. In the US, the average individual daily use of water is ~159 gallons, while more than half the world’s population lives on less than 25 gallons per day! Wearing my favorite shirt day after day serves a greater purpose.”
3. Real Green Men don’t complain about physical discomforts. Social pressures sometimes force real men to turn up the thermostat during the winter. But real men are tough, and they view physical stress as a challenge. Armed with the knowledge that raising your thermostat down by two degrees F in winter and up by two degrees F in summer can decrease your carbon emissions by 2,000 pounds per year, a Real Green Man can display his manliness with bold displays of thermoregulation.
4. Real Green Men make things from scratch. The centers of all of the world’s oceans are filled with particles of plastic, with devastating consequences for the marine ecosystem. There are many ecological costs associated with plastic waste, including the fact that they can release hormone-mimicking substances that may alter sexual development and increase cancer risk in humans and other animals (for a case study, see Nancy Langston (2010) Toxic Bodies). Real men know how to build things, to fix things, and to grow things. Real Green Men know that making things themselves also means that they don’t have to buy everything that comes in ultra-durable plastic wrapping.
5. Real Green Men aren’t lazy. At some point, men became associated with inventions that make life easier – leaf blowers, snow blowers, riding mowers. But real men don’t use these tools. They use their massive shoulders and thick forearms. They’d rather grunt and grown with a rake or a shovel than use the tools of decadence. According to the US Environmental Protection Agency, one gas lawn mower spews 88 lbs. of carbon dioxide and 34 lbs. of other pollutants into the air every year. A new gas mower produces as much CO₂ per hour as 11 cars; older versions are even worse. A Real Green Man not only knows the value of using his brawn, and he also knows the impact he can have on the environment.
6. Real Green Men eat meat (but only if it’s an invasive or pest species). What could be manlier than bringing down a wild animal and using the meat to provision one’s family and friends? Even Hollywood knows: Real men hunt. But what about Real Green Men? There are certainly ecological reasons for a Real Green Man to be a vegetarian. Given that only about 10% of the energy at one trophic level (e.g., plants) is transferred up to the next trophic level (i.e., herbivores), eating lower on the food chain as a vegetarian is much more efficient than eating as a carnivore. But the primal urges are strong in the Real Green Man, and he yearns to track, capture, and overcome his prey. And he likes the taste of meat. Must he satisfy himself with attacks on mock duck? No. A Real Green Man can hunt and have a positive effect on his environment at the same time, as long as he targets invasive and pest species. Invasive species are having an increasingly large effect on native ecosystems – their spread is largely due to human commerce and other economic activities. One idea for controlling invasive species that is getting attention is to promote them as dinner items. For example, the lionfish – an invasive species that is having a devastating effect on reef-dwelling fish communities in many tropical areas – apparently tastes delicious! The Real Green Man can even hunt deer – a traditional favorite of many real men hunters – because deer populations are well above long-term average abundances in many areas. Of course, the Real Green Man is well informed, and knows how the specifics of his actions affect the environment. For example, trapping lionfish can ensnare native fish instead, so spearfishing is the right strategy for the Real Green Man. And a Real Green Man would not support managing an ecosystem to support his hunting needs – a Real Green Man doesn’t need a handout.
   

   a delicious lionfish - watch out for the spines

Does the Real Green Man have a future? I hope so, because we need him for the environmental war effort. Greening up may also do wonders for the traditional real man by giving him a way to lead his community to a more promising future.

Population ecology and the coming of the zombie apocalypse

In 300 A.D there were 50-60 million humans, by 1804 there were 1 billion, and last week, the UN reported that there are now 7 billion of us. And more are coming. Given that the planet has a limited resource base, the human population cannot grow forever. Demographers describe constraints on population growth with a metaphor, the carrying capacity, which is the maximum population size that a habitat can support indefinitely. Population growth rate decreases to 0 as the population size approaches the carrying capacity. The processes that bring about this decrease in population growth rate are called negative density-dependent factors. These factors include the crappy aspects of civilization – food and shelter scarcity, violence among individuals, higher risk of disease, waste accumulation – as well as behaviors that reduce birth rates. As of now, resource use per person is still increasing as the global economy continues to grow (albeit unevenly). But it’s impossible for the human population to increase in size indefinitely – even if technology increases resource use efficiency. Population growth rates will decrease, and this decrease will be due to negative density-dependent factors. Hopefully, we’ll figure out a way to reduce birth rates and resource use rates without mayhem. I’m not optimistic.

And I don’t think I’m alone in this view. My feeling is that people are getting a stronger sense that human impacts on ecosystems are becoming increasingly severe and show no signs of abating. These impacts will cause greater and greater challenges for us, but how exactly they will affect population growth and resource use is unclear. Will there be gradual modifications in lifestyles until we emerge as a globally sustainable society? Or will there be catastrophic transitions that massively restructure society? I imagine that most people have a general sense that the world is crowded, it’s getting more crowded, and this trend can’t continue forever. They feel that change is coming, but they are uncertain about what that change will look like.

So what’s going to happen? One option that is getting a lot of attention is a zombie apocalypse. The idea of zombies originates from the depiction in Haitian culture of bringing corpses back to life using witchcraft. In modern culture, the zombie concept was popularized by the classic 1968 film “Night of the Living Dead”, in which the dead become re-animated and then seek out the living as food. Although the zombie concept has remained a part of American culture since that time, its prevalence has exploded over the last few years. A quick search for “zombies” on amazon.com brings up over 30 titles (!) published since 2006, including “The Zombie Survival Guide: How to Live Like a King After the Outbreak” by Etienne DeForest, “Pride and Prejudice and Zombies: The Classic Regency Romance – Now with Ultraviolent Zombie Mayhem!” by Jane Austen and Seth Grahame-Smith, and one that I highly recommend, “World War Z: An Oral History of the Zombie War” by Max Brooks. I’m currently reading “Zone One” by Colson Whitehead, about a military unit assigned to “eliminate” any remaining zombies in New York City about 2 years after a zombie apocalypse. I started reading this book because of all of the critical acclaim it’s received; the New York Times described it as “a cool, thoughtful and, for all its ludic violence, strangely tender novel, a celebration of modernity and a pre-emptive wake for its demise.” But I’m still trying to figure out why the zombie genre has become so popular, and I wonder if it has to do with global ecology.

Zombieism is a strong negative density-dependent factor. It’s interesting that the cause of zombieism in “Night of the Living Dead” was the release of radiation from a satellite. That was 1968 – the height of the space age and the threat from the great Communist menace. In today’s literature, zombieism is a combination of cannibalism (zombies eat humans) and an emerging infectious disease (getting bit by a zombie gives you the zombie plague, which kills you (within hours or days) and then re-animates you (within minutes) hungry for human flesh). In the real world, cannibalism occurs in a variety of species and often becomes more prevalent at higher population densities. My favorite example of cannibalism is from the spadefoot toad genus Spea, a group of desert-dwellers that inhabit rain-filled pools. Spea tadpoles often have to mature rapidly to reach adulthood before ephemeral ponds dry up. Conditions indicating high tadpole densities trigger the development of a cannibalistic Infectious disease transmission is more likely when population density and contact among members of the same species are high. Cannibalism and infectious disease can be interconnected. For example, tiger salamanders are more likely to develop a serious hemorrhagic disease when they eat infected members of their own species. In humans, observations of a Papua New Guinea tribe have shown that eating human brains increases the risk of catching the deadly disease kuru. 

Zombieism is an even tighter connection between cannibalism and infection disease. For the zombie disease, the plague actually leads to cannibalistic behavior. In fact, it seems to create a singular and insatiable drive for the flesh of the living. Every successful attack spreads the disease, and the positive feedback can quickly lead to an apocalypse. (The dynamics of this disease have actually been modeled in a book on host-disease interactions). The only hope for the living is to create a well-protected refuge and hone your anti-zombie defensive skills (you can kill a zombie by destroying its brain).morphology, and the ensuing carnage leads to a reduction in population size. Infectious disease transmission is more likely when population density and contact among members of the same species are high. Cannibalism and infectious disease can be interconnected. For example, tiger salamanders are more likely to develop a serious hemorrhagic disease when they eat infected members of their own species. In humans, observations of a Papua New Guinea tribe have shown that eating human brains increases the risk of catching the deadly disease kuru.

So how is the recent explosion (epidemic?) of zombie literature related to today’s population ecology? Maybe zombie literature describes a type of worst-case scenario as the world gets more crowded and our natural support systems become more degraded. Imagining worst-case scenarios may prepare us psychologically when (if?) real chaos actually emerges. And even though the destruction brought about by a zombie apocalypse is horrific (even parts of the campy “Night of the Living Dead” are hard to watch), the end result is a massively reduced population size and a lot of civilization’s infrastructure left intact. That scenario will have broad appeal. Survivors of the zombie apocalypse won’t need to think about the ecological consequences of their actions – they’ll be able to use a leaf blower while sitting in their Hummer without having to think about what some crazy environmentalist has to say about it.Life will be good. So it might be time to hone your skills as a writer of zombie literature; that fantasy may become even more appealing for us in the future as the impact of climate change and habitat destruction become even more acute. Or, better yet, learn how to slay zombies.   

Humanity’s future is bright, or maybe it’s not

The United Nations last week reported that the earth’s population has now reached 7 billion. The 7 billionth person doesn’t change our social or ecological conditions in any fundamental way, but the milestone provides an opportunity for reflection on broad trends. What is in store for this mass of humanity? Will more creative minds give us a better opportunity to develop technologies that enhance our quality of life? Or is the impact on the global ecosystem of so many humans moving us toward a catastrophic collapse?

I’ve been struck recently by how variable the answers to these questions are, even among experts in global development and human demography. In particular, two recent books on humanity’s future that have received a lot of attention, “The Great Disruption” by Paul Gilding and “Getting Better” by Charles Kenney, paint such distinct pictures of our current conditions and challenges that I thought it would be worthwhile to contrast their assumptions and interpretations.

Gilding’s title refers to the massive societal reorganization that he argues will inevitably occur as a result of climate change and other human impacts on global ecosystems. He points to evidence that humans long ago passed the planet’s limits to supply our resource needs and to absorb our waste. One area of emphasis is work by the Global Footprint Network, which estimates the amount of natural resources needed to maintain our economy and lifestyle. The estimates are frightening: humans overshot the earth’s carrying capacity in 1985; in 2009, we needed 1.4 planets’ worth of ecological services to support our activities (the short-term overshoot is possible because of reliance on fossil fuels and other non-renewable resources). He also describes the evidence for the connection between climate change and human activities, identifies the likely scale of the near-term problems associated with climate change, and states that there is essentially no disagreement among scientists about these general conclusions.

The main thrust of Gilding’s presentation is that because we are already significantly past the earth’s carrying capacity and the pressure of humans on the global ecosystem is only going to increase, the die has already been cast and we are headed for calamity. “This means that assumptions we make about global society – that we will bring the poor out of poverty, that we will carry on creating jobs, food, and basic needs for the more than two billion new global citizens and the existing seven billion or so, that we in the West will continue to increase our financial and material standard of living, that the world, despite conflicts here and there, will carry on in relative stability – are a grand delusion.” Instead, he predicts massive turmoil leading to a major reorganization of society focused on sustainability and a more equitable distribution of resources across the global population. What’s inspiring about Gilding’s argument is that he argues convincingly that the knowledge and the resources are available to guide a societal transformation to sustainability. We know what to do – implement cap-and-trade systems for dealing with emissions of carbon and other pollutants, massively invest in renewable energies, start government programs to reduce consumer consumption in developed countries, etc. – and he argues that when people feel the full force of the Great Disruption, they will support these measures with the same passion and verve that populations in the past have shown when facing existential threats in war.

Charles Kenny’s book, Getting Better, provides a much more optimistic view about the state of the world. He argues convincingly that the collective well being of the human population has never been better. Almost every per capita indicator of human welfare – income, child survival rates, longevity, infectious disease prevention, reductions in violence, gender equality, adult literacy rates, democratization – have all increased substantially across the globe over the last 50 years or more. Moreover, the overall pattern in these measures has been toward convergence among countries – quality-of-life measures in poorer countries are increasing faster than in richer countries. He shows that even in areas of the world in which per capita income and gross domestic product (GDP) have stagnated over the last 50 years (as in much of sub-Saharan Africa), other quality of life measures have significantly improved. For example, in 12 countries that had a decrease in GDP from 1960 to 2005, life expectancy increased by an average of 10 years, and adult literacy rates closed to doubled on average. His main conclusion is that much of the improvements that we refer to as “development” can be brought about through the creation, spread, and application of ideas and technologies for improving the quality of life that do not require an increase in income and its associated ecological costs.

I found the core message in Kenney’s book noteworthy and inspiring. It’s too easy to lose sight of the tremendous improvements in the general quality of human life over the last century given the current inequities, calamities, and environmental challenges. Things are generally better, and general improvements can lead to further improvements as people begin to expect health, education, and equal opportunities. However, he largely sidesteps the issues of resource depletion and climate change. These issues are viewed as another challenge that the global development community can take on, rather than as the inevitable cause of catastrophe that will radically transform society.

These very different perspectives on the future of the global society made me think of an ecology talk I recently attended by Mike Pace from the University of Virginia. He and his colleagues provided evidence that an increase in the variability of key features of an ecosystem (in this case, the amount of chlorophyll a (a measure of productivity) in a lake ecosystem) was an indicator of an upcoming “regime shift”, a substantial and largely irreversible change in the state of an ecosystem. So are highly divergent views on the global condition the sign of a pending global “regime shift”? Let’s hope not, but it’s certainly time to get to work.

Why I like Biology

(Note: I wrote the essay below for a popular science blog. It didn’t get published, but I can publish it here and I hope it’ll get the ball rolling with this blog)

I like biology because it has helped me understand who I am and how I fit into the world around me. As an undergraduate student, I struggled to understand why conflict and suffering seemed to be an inevitable aspect of the human experience. I searched for answers as a religious studies major at the University of North Carolina, but I never found anything deeply satisfying until I stumbled across E.O. Wilson’s “Sociobiology”, a wonderful book that describes social behavior from microbes to mammals. By the time I finished the famous final chapter, “Man: From sociobiology to sociology”, I was convinced that evolutionary biology had enormous potential to help explain human nature. Over time, I found that core evolutionary theory about social interactions – kin selection, parent-offspring conflict theory, sexual selection – provided explanations for my motivations that were far more satisfying than anything else I had been exposed to. Now, as a researcher and professor studying behavior, I have learned that ideas about the evolutionary underpinnings of human behavior are novel, interesting, and often challenging to students trying to figure out meaning and purpose in their world. Studies from the natural world describing complex behavior help students feel more connected to nature. One of my favorites is a study by Jeffrey Hoover and Scott Robinson that describes how cowbirds, which lay eggs in the nests of songbirds, use mafia-like behavior to ensure that the parasitized songbirds rear rather than destroy the cowbird eggs (Hoover and Robinson 2007). At the same time, studies of the adaptive significance of modern human behavior, for example the studies by Randy Thornhill, Steven Gangestad and others showing how odor attractiveness is sub-consciously associated with body symmetry (e.g., Thornhill and Gangestad 1999), or the study by Melissa Bateson and colleagues showing how the presence of a photograph of human eyes increases contributions to an honesty box (Bateson et al. 2006) often give students new insight into the motives underlying their social interactions. Given the complexities of modern life and the incredible challenges facing the global population, I hope that self-awareness gained through biology will help us understand causes and find remedies for our social ills.

An eastern phoebe nest with a parasitic brown-headed cowbird chick (click on the photo for credits)

Bateson M, Nettle D, Roberts G (2006) Cues of being watched enhance cooperation in a real-world setting. Biology Letters, 2, 412–414.

Hoover JP, Robinson SK (2007) Retaliatory mafia behavior by a parasitic cowbird favors host acceptance of parasitic eggs. Proceedings of the National Academy of Sciences of the United States of America, 104, 4479-4483.

Thornhill, R., & Gangestad, S. W. (1999). The scent of symmetry: A human pheromone that signals fitness? Evolution and Human Behavior, 20, 175-201.

Our New Blog!

The field of Biology has relevance for many of our major societal challenges and opportunities. Faculty in the Biology Department at the University of St. Thomas conduct research and teach classes that address societal issues, but we are also interested in generating a dialogue and sharing information with a broad community. The aim of this blog is to give department members an opportunity to share  information about their research, their teaching, their philosophy, or their opinions on recent biology-related news. We encourage comments on all posts. If guests (e.g., current students, department alums, other visitors) would like to post an entry, you can contact adam kay (adkay@stthomas.edu). Please include the phrase “Biophilia Blog entry” in the title of the email.