- Author: Kathy Keatley Garvey
"He is slim and intense, with graying hair and clipped sentences jagged with inflections from his years in Brazil and Japan. And he does not, perhaps cannot, quit."
So wrote freelance journalist Carrie Peyton Dahlberg, formerly with the Sacramento Bee, in her excellent profile of chemical ecologist Walter Leal, published today on the American Association for the Advancement of Science website.
Leal, professor of entomology at the University of California, Davis, "tries to understand at the molecular level exactly what an insect is smelling, and how it relies on scent to interact with the world," she wrote.
Her article included a great quote from Leal's colleague, John Hildebrand, a neurobiology professor at the University of Arizona, Tucson.
“He’s one of the most dynamic people in the field. He’s a remarkably energetic and passionate person about his work … and notorious almost for the rapid fire way he speaks. He loves to joke that he can say twice as much in a lecture as anyone else because he only says half of each word.”
It was the Leal lab that discovered the secret mode of DEET. The groundbreaking research proved that “DEET doesn’t mask the smell of the host or jam the insect’s senses," Leal said in a UC Davis Department of Entomology news story. "Mosquitoes don’t like it because it smells bad to them.”
DEET’s mode of action or how it works puzzled scientists for more than 50 years. The chemical insect repellent, developed by scientists at the U.S. Department of Agriculture and patented by the U.S. Army in 1946, is considered the "gold standard" of insect repellents worldwide. Worldwide, more than 200 million use DEET to ward off vectorborne diseases.
Scientists long surmised, incorrectly, that DEET masks the smell of the host, or jams or corrupts the insect’s senses, interfering with its ability to locate a host. Mosquitoes and other blood-feeding insects find their hosts by body heat, skin odors, carbon dioxide (breath), or visual stimuli. Females need a blood meal to develop their eggs.
In her article, Peyton Dahlberg said Leal is trying to find something better than DEET.
Wrote Peyton Dahlberg: "DEET is a flawed tool, a chemical that needs to be used at high doses, can affect human biology, and isn’t recommended for very young infants, according to Leal and others who have studied it. The point is finding something better than DEET, something more targeted to the most problematic insects and less dangerous for everything else, including people."
Leal told her that that to search for safer alternatives to DEET and other insecticides, researchers need to better understand the mechanisms of scent detection and chemical communication.
Leal indeed has a "nose for insects' sense of smell," as the AAAS headline pointed out.
- Author: Kathy Keatley Garvey
It's quite an honor to be elected a Fellow of the American Association for the Advancement of Science (AAAS).
And it's a double honor when two persons from the same department at the same university receive the honor the very same year.
That's what happened today.
Professors Richard "Rick" Karban and Jay Rosenheim of the Department of Entomology, University of California, Davis, were both named Fellows. They're among the 531 new Fellows announced today--with eight from UC Davis. Fellows are selected by their peers for their “scientifically or socially distinguished efforts to advance science or its applications.”
Karban was selected for “distinguished contributions to the field of plant-herbivore interactions, particularly for work on induced plant resistance and volatile cues used by plants” and Rosenheim for “distinguished contributions to the field of ecology, particularly for empirical and theoretical contributions to our understanding of insect predator-prey and host-parasitoid interactions.”
Rosenheim and Karban share a love of entomology, research and teaching. You can read more about their accomplishments here.
The UC Davis Department of Entomology now has a total of seven AAAS Fellows: James Carey, elected in 2000; Bruce Eldridge, elected in 1981; Waler Leal, 2006; Robert Page (UC Davis emeritus professor who's now at Arizona State University), 2006; Thomas Scott, 2007, and now Karban and Rosenheim
Rosenheim, who joined the UC Davis Department of Entomology faculty in 1990, received another outstanding honor earlier this year: he was honored by the Associated Students of UC Davis for excellence in the classroom. In fact, he was singled as the most outstanding teacher in the College of Agricultural and Environmental Sciences.
And Karban? Since joining the UC Davis Department of Entomology in 1982, he's graduated 14 graduate students or post-docs; 13 are professors at top institutions, including UC Davis (3) and Cornell (3).