ature rules this place, and with a mahogany fist. She has decreed this forest to be no gentle glade, but a biological battleground, where each species fights for her favor. All the creatures great and small employ their own offensive tactics. Strangler figs wrap their roots around the mammoth trees, thrusting branches upward toward the light. The trees duel for their place in the sun, crushing younger offspring with massive plummeting branches and stifling them beneath light-blocking foliage. And the animals—goldenrod-yellow eyelash vipers, ghost-like jaguars, inch-long bullet ants, and deceptively dainty poison dart frogs—all wield their own weaponry to protect and to kill.

Even the water seems a liquid life form. Like an insect metamorphosing from egg to larva to adult, moisture here can transmute from a steamy, smothering humidity, to a gently pattering shower, to a roaring deluge that drenches the forest. In mere hours, the downpour can turn a river from a placid stream into a roiling brown flood that sweeps away massive logs as if they were twigs.

This is La Selva Biological Station of the Organization for Tropical Studies (OTS)—3,900 acres comprising a diversity of life that is a microcosm of the awe-inspiring ecological wealth of the tropics, in general, and Costa Rica, in particular. The scientists here revel in La Selva’s biological drama—and in its profound scientific mysteries. Living within the station’s thick forests are 1,700 plant species—460 species of trees alone; more than sixty species of bats; 463 species of birds; and 600 species of ants. The station boasts some 7,000 species of butterflies and moths, fully half the number of species in the entire North American continent north of Mexico.

Lighting bugs: Jadranka Rota selects specific moths for specimens at a collecting station in La Selva

As a sprawling international consortium of some sixty-five universities and research institutions, OTS is among the world’s most successful organizations for fostering tropical research and education. The center’s biological stations attract hundreds of visiting scientists every year to study tropical ecology. And OTS sponsors courses to teach students, park managers, and policymakers about tropical ecology and conservation science and policy. OTS has maintained its U.S. headquarters at Duke since 1976, when Donald Stone, now professor emeritus of biology, became the organization’s executive director. Under Duke’s agreement with OTS, recently extended for another half-century, OTS staff members are classified as Duke employees, and the organization’s researchers can hold adjunct positions at the university.

La Selva is one of three Costa Rican research stations operated by OTS. The others are at Las Cruces and Palos Verde. The organization is also planning a new academic center at the University of Costa Rica and is looking for ways to export its model of research and teaching to countries in Africa and Asia by joining with local universities, wildlife parks, and conservation organizations.

At all of OTS’s biological stations, visiting biologists do science across the breadth of space, time, and technology. They take scientific measurements throughout its thickly forested landscape, hoist themselves into its treetops, and sink cores deep into its sediments. They rouse themselves as the earliest morning light filters down through the luxuriant green foliage and work long into the night, their puny headlamps attempting to hold back the utter blackness that shrouds a nocturnal rain forest. And, they use implements ranging from the most basic rubber boots to the latest in digital computer imaging.

The discoveries they have made here range from the poetically inspiring—a new butterfly or ant species—to the darkly disquieting: hints that the global increase in carbon dioxide could decimate tropical forests.

“Many ecologists have learned that long-term data sets that span decades are extraordinarily valuable. We have projects that have been going on here at La Selva for up to forty years.” GARY HARTSHORN, President, Organization for Tropical Studies

Last April, OTS’s leaders and researchers gathered to observe the organization’s fortieth anniversary with a banquet, a symposium on the future of tropical science, and a “rubber boot camp” field experience. One boot camp found a group of timorous, amateur biologists trailing a stalwart young graduate student into the forbidding gloom of a tropical night to trap bats. The mission was to track the bats’ movements and hunting and feeding habits. The nocturnal excursion gave a fascinating taste of what it takes to be a bat researcher, which includes some rather unexpected skills. The novices learned to untangle a wispy “mist net” and string it across a trail in the pitch-black darkness, as if preparing for some exotic, tropical badminton game. But in this case, the shuttlecocks were squirming, squeaking balls of fur, ill-tempered at being interrupted on their nightly feeding flights by becoming tangled in a net—extremely tangled, in many cases. The novices had to learn the delicate art of extricating a bat from a snarl of fine nylon while avoiding the creature’s angry nips.

The effort yielded a fantastic harvest—dozens of gorgeously ugly bats for examination by the group. There were tiny, snowball-like, Honduran white bats, which spend their days nestled beneath banana leaves, whose veins they snip to fold over themselves like sleeping bags. And there were the sharp-toothed vampire bats, masters of the stealthy art of gliding up to animals and opening a tiny wound to drink their blood. Each of the bats was measured and weighed, and then offered a dollop of banana baby food as recompense for the indignity of capture. They stuck out tiny, unexpectedly pink tongues to lap up the treat. Afterward, they were carefully transferred to a nearby branch, where they hung like bizarre ornaments on an Addams Family Christmas tree, until they recovered and flew away.