Science Wednesday: Biodiversity, Mosquitoes, and Health, Oh My!
Wednesday, September 16th, 2009
Each week we write about the science behind environmental protection. Previous Science Wednesdays.
It was 0630 and although the sun was beginning to rise, it was still very dark within the tropical forest. Following a 20 minute ride in a small boat, we had arrived at a remote trail on the island and were now navigating the trail to check the CO2/light traps set the night before. The illuminated traps were beacons in the sea of dark forest, and we hoped they’d be filled with mosquitoes. The forest was peaceful in the early morning light, except for the occasional bouts of grunting from the howler monkeys or an agouti crossing the trail.
I never imagined working at EPA would lead me to Barro Colorado Island (BCI), a former mountain top that became an island when the Panama Canal was created in the early 1900s. Now a natural monument, it was the setting of the inaugural sampling event for a joint project between EPA and the Smithsonian Tropical Research Institute (STRI).
The project explores the link between biodiversity, insect vectors (those capable of passing a pathogen one animal to another), and disease. The connection between biodiversity (the number and abundance of difference species) and disease is complicated, but we know that sometimes changes in biodiversity (specifically, the loss of structural diversity) can increase the abundance of certain disease-carrying vectors. In turn, this can increase the risk of humans coming into contact with the disease-transmitting vector. Human activities, such as encroaching into new areas to build houses or clear land for farming, can change local biodiversity.
The STRI-EPA project focuses on mosquitoes and how changing biodiversity in “natural” and anthropogenic landscapes affects vectors of public health importance.
Back at the lab, we began the monumental task of sorting through the traps’ contents. Thankfully, I was surrounded by insect experts who were able to show me exactly what to look for among the tiny copious critters. Microscope and forceps in hand, I started sorting and sorting…. Hours later, sorting complete, we separated mosquitoes and sandflies (another vector important to public health) by species into groups of 50 or fewer. Specimens were placed into vials and frozen. The samples will be analyzed later to see what kinds of pathogens the insects were carrying, if any.
Over this next year, sampling will continue at BCI. We plan to expand sampling into nearby, land-disturbed areas inhabited by people so that mosquito diversity and disease risk can be compared with that of BCI.
About the Author: Meghan Radtke, Ph.D. is an AAAS Science and Technology Policy Fellow at EPA. Her fascination with biodiversity and tropical forests inspired her to join the Biodiversity and Human Health research effort.

Through my research, I am looking at the intersection of conservation and economics related to harvesting C. guianensis. I am using ecological models with an economic component to answer the question: Under what ecological and market conditions would the collection of C. guianensis seed oil be favored and, conversely, under what ecological and market conditions would C. guianensis timber harvest be favored?
The landscape we flew over is the subject of the
Our flight took us over the Willamette River as it winds from Corvallis to the suburbs of Eugene, a diverse and productive landscape. Over the drone of the engine and intermittent blasts of cool air that roared into cockpit when Eric opened his window to take pictures, Steve explained what he was seeing from a scientist’s perspective: how the flow and course of the river has been shaped by human forces, the patterns and types of forest and other natural habitats, what types of crops where growing in the large agricultural fields below, and the shifting boundaries between agriculture, forest, and what he referred to as “the built environment” (homes, roads, and industry, including the massive paper mill we could not only see, but smell—a thick, burnt-syrup kind of aroma).
I first had that chance in 2007 when I traveled to Alaska and met people from several Native Alaskan villages such as