- Author: Kathy Keatley Garvey
Walter Leal isn’t participating in the Olympics, but he medaled just the same.
It was not for athletic prowess, but for scholarly achievements—the scientific equivalent of an international gold medal.
Leal, a chemical ecologist and a professor and former chair of the UC Davis Department of Entomology, is the recipient of the coveted Silver Medal, the highest award given by the International Society of Chemical Ecology (ISCE).
A native of Brazil and educated in Brazil and Japan, Leal researches how insects detect smells and communicate within their species. He is “one of the foremost authorities on the integration of chemical ecology with the molecular, biochemical and physiological interactions among insects and between insects and plants,” said chemical ecologist Coby Schal, professor at North Carolina State University, who nominated him for the award.
Bruce Hammock, UC Davis distinguished professor of entomology, wrote a letter of support, praising Leal for “his outstanding career achievements and excellence in moving chemical ecology forward." Hammock described him as “a world-renowned chemical ecologist, a pioneer in the field of insect olfaction, and on the cutting edge of research.”
ICSE president Paulo H. G. Zarvin of the Federal University of Parana, Brazil announced the award July 26 at the 28th annual ISCE annual meeting, held in Lithuania. It will be presented at the ISCE’s 29th annual meeting, set Aug. 19-22, 2013 in Melbourne, Australia.
Declaring Leal’s program, launched in 1990, as “one of the best in the world,” Schal lauded Leal as “one of the most energetic and collaborative scientists I know.”
“Chemical signaling is fundamental to all life forms, including microbes, plants and animals,” Schal said,” and chemical cues allow animals to appraise their environment; to detect food, toxins, prey, predators and pathogens; to identify kin; and to evaluate and base mate choice decisions of potential reproductive partners.”
“Walter’s research, in two decades, has addressed almost every aspect of chemical ecology,” Schal said. That includes “the semiochemistry of mites, thrips, scarabs, bugs, aphids, cockroaches, moths, wasps and plants.”
Leal, who joined the UC Davis faculty in 2000, has designed and synthesized complex pheromones from many insects, including scarab beetles, true bugs, longhorn beetles and the citrus leafminer. He identified the complex sex pheromone system of the naval orangeworm, a key agricultural pest responsible for multi-million crop damage annually in California. The sex pheromones he discovered are now being deployed in the agricultural field to disrupt chemical communication and control the navel orangeworm population through the environmentally friendly technique of mating disruption.
Leal and his lab discovered DEET’s mode of action, something that had puzzled and eluded scientists for half a century. Scientists long surmised that DEET, patented by the U.S. Army in 1946, works by masking the smell of the host, or jamming the insect’s senses, thus interfering with its ability to locate a host. Not so: in groundbreaking research published in the Proceedings of the National Academy of Sciences (PNAS), the Leal lab found that mosquitoes can indeed smell the chemical repellent but they dislike it so they avoid it.
Leal is one of only 23 scientists to receive the ISCE Silver Medal since its inception in 1986. Two other University of California scientists also won the award: Dave Wood of UC Berkeley in 2001 and Ring Cardé of UC Riverside in 2009.