Scent-sational Science

To trace the course of evolution, Kim Steiner follows his nose.

The "ghostwriters" behind some of your favorite smells, the Swiss scent specialists at Givaudan power perfumes by Calvin Klein, Cartier and even Michael Jordan. They also power evolutionary research by Academy scientist Kim Steiner.

Steiner, who is studying the evolutionary relationship between a flower's scent and its pollinators, recently returned from a trip to South Africa, where he analyzed the aromas of orchids with the help of equipment and expertise from Givaudan. To collect a scent to study, Steiner would invert a glass dome over one or more flowers and pump the scent-infused air though a chemical "trap" that captures passing fragrances. He would then send the traps to his collaborator, Roman Kaiser, in the research labs of Givaudan. After extracting the scents from the traps, Kaiser would inject them into a gas chromatograph-mass spectrometer that can identify the amounts and kinds of chemicals that make up a fragrance. Givaudan uses this data to inspire new designer perfumes or candle scents. Steiner uses it to understand how floral scents evolve among closely-related species that share a specialized pollination system.

Oil-producing orchids in the subtribe Coryciinae were the focus of Steiner's recent research. These pungent, soapy-smelling flowers are mostly pollinated by a single species of solitary oil-collecting bee. Now that Steiner knows the secrets of their scents, he can trace their evolution on the orchid family tree.

Apparatus used by Steiner to sample the scents of orchids in the field. A small battery-powered pump is used to draw the fragrance, given off by the flowers, through the chemical "trap" at the tip of the plastic tubing. The pump has to run for several hours to obtain enough scent for a chemical analysis.
Photo: Kim Steiner

Mountain shrublands of the Cape Peninsula. View towards Chapman's Peak and Noordhoek beach from the Constantiaberg, the highest mountain on the Cape Peninsula. After fires, orchids abound in these mountains, and many of them have distinctive floral scents. Photo: Kim Steiner

Pterygodium catholicum, from the lower slopes of Chapman's Peak. This is a common terrestrial orchid in the western Cape of South Africa. It has a distinctive "soapy " fragrance due primarily to the presence of dodecanol and caprylic acid. Photo: Kim Steiner
Map by Colleen Sudekum