- Author: Kathy Keatley Garvey
The female silkworm moth releases a sex pheromone, bombykol, that's very enticing to the male. He can detect it from miles away.
Now researchers in the UC Davis Department of Entomology have discovered that the fruit fly has a native odorant receptor that detects the silkworm moth’s sex pheromone, and that it’s “amazingly more sensitive” than the moth’s odorant receptor.
Their work could open research doors for insect-inspired biosensors.
Walter Leal, professor of entomology, and postdoctoral scholar Zain Syed know the olfactory systems of silkworm moths (Bombyx mori) and fruit flies (Drosophilia melanogaster) well.
In a serendipitous discovery, the chemical ecologists found that the fruit fly’s odor detector not only detects bombykol, but responds to bombykol with high sensitivity. Their groundbreaking research, Bombykol Receptors in the Silkworm Moth and the Fruit Fly, was published May 3 in the Proceedings of the National Academy of Science (PNAS).Their research follows on the heels of another study they published in PNAS in 2006 with the Deborah Kimbrell genetics lab in the UC Davis College of Biological Sciences. Bottom line: they found that genetically engineered fruit flies responded to the silkworm moth scent of a female.
Now Leal and Syed have identified the odorant receptor in the male fruit fly that detects the sex pheromone.
Ecologist and evolutionary biologist Fred Gould of North Carolina State University, not affiliated with the research, says the work of the UC Davis researchers "provides important guidance and tools for other researchers who want to explore the pheromone communication systems of other species, or who want to further dissect the mechanisms within the specialized hairs of silkworms that enable this high sensitivity.”What we have here with the silkworm moths and fruit flies is definitely not a "failure to communicate."
- Author: Kathy Keatley Garvey
Charles W.Woodworth would have been proud.
When the C. W. Woodworth Award, the highest award offered by the Pacific Branch of the Entomological Society of America (PBESA) was awarded this week to chemical ecologist Walter Leal, professor of entomology at UC Davis, it linked two entomology trailblazers.
Woodworth (1865-1940), considered the founder of both the UC Berkeley and UC Davis departments of entomology, is an entomological legend. Leal is a worldwide authority on the relatively new field of insect communication and olfaction.
Woodworth's great-grandson, Brian Holden of Monte Sereno, Calif., attended the PBESA meeting in Boise, Idaho, to present the award.
“Because of his deep and meaningful body of work over the last 10 years, Dr. Walter S. Leal of UC Davis is a wonderful selection as the 42nd recipient of the C.W. Woodworth Award," said Holden, who is writing a book on his great-grandfather. "His research into the detailed neuronal responses in mosquitoes to DEET and nonanal has been particularly impressive. His research has improved our knowledge of mosquito behavior in the presence of these two compounds, both of which are central in the efforts to understand and control mosquito-borne illness."
Both Leal and Holden are closely connected to UC Davis. Leal joined the Department of Entomology 10 years ago and served as department chair. Holden received his bachelor of science degree in electrical engineering from UC Davis in 1981.
If you look on Wikipedia, you can glean information about the remarkable career of C. W. Woodworth and the award. His great-grandson researched and wrote the entries.
If you look on the UC Davis entomology Web site, you can read about the remarkable work of Walter Leal.
Two trailblazers.
- Author: Kathy Keatley Garvey
It's a killer, pure and simple.
But the issue is as complex as it comes.
The malaria mosquito, from the genus Anopheles, infects some 350 to 500 million people a year, killing more than a million. Most are young children in sub-Saharan Africa.
Female mosquitoes “bite” because they require a blood meal to develop their eggs. They detect their prey via olfactory receptor neurons found on their antennae, the insect equivalent to the human “nose.”
When Anopheline mosquitoes are infected with a parasite that causes malaria, the insect-host transmission occurs. The result: a deadly killer.
Identifying exactly how malaria mosquitoes detect their human prey is crucial to developing strategies for mosquito control, says chemical ecologist Walter Leal, professor of entomology at the University of California, Davis.
Leal, recently asked to write a "News-and-Views" piece on a Yale-Vanderbilt study for the international science journal, Nature, did so eloquently in its March 4th edition. He praised the scientific report as a “milestone discovery in our understanding of the malaria mosquito’s sense of smell.”
In the article, headlined "The Treacherous Scent of a Human," Leal zeroes in the widespread threat of malaria, a disease that threatens half of the world’s population. It's "an accessory to the deaths of about one million humans every year,” Leal wrote. “Globally, the number of people who get malaria each year is greater than the population of the United States.”That's putting a number on the numbers.
The Yale-Vanderbilt team, headed by John Carlson of the Yale Department of Molecular, Cellular and Developmental Biology, examined 79 of the malaria mosquito’s odorant receptors, finding that some are well-tuned to detect specific human odors and others aren’t. Certain odorants activate some receptors but inhibit others, according to their comprehensive study published March 4 in Nature.
Indeed. The Leal lab back in 2008 published groundbreaking research that revealed the secret mode of the insect repellent, DEET. The scent doesn't jam the insect senses and it doesn't mask the smell of the host, as scientists previously thought. Mosquitoes avoid it because it smells bad to them.
Leal advocates more molecular studies in the war against malaria and other mosquito-borne diseases. But that research can't stand alone. As he succinctly points out: “The development of effective malaria control will require a multidisciplinary approach that includes, but is not limited to, improvements to social infrastructure in countries affected by disease, vaccination programs and vector management.”
New mosquito attractants or repellents, he says, could be developed through reverse chemical ecology, determining which odorant attracts and which repels.Mosquitoes don't like the scent of DEET. What else do they NOT like?
The study, as Leal correctly observes, "offers a fresh strategy for controlling the unwitting accessories to one of the world’s most prolific killers.”
- Author: Kathy Keatley Garvey
Human blood--it drives mosquitoes wild.
Today Marlene Cimmons of the National Science Foundation (NSF) spotlights chemical ecologist Walter Leal, professor of entomology, University of California, Davis, on the LiveScience Web site.
This interesting feature takes a behind-the-scenes look at Leal, a Brazilian-born scientist trained in three countries: Brazil, Japan and the United States.
His research, partly funded by a NSF grant, has received international acclaim. Last year he was elected a Fellow of the 6000-member Entomological Society of America, a prestigious honor reserved for only 10 or fewer scientists a year.
Leal, who focuses his research on how insects detect smells, is not shy about being a human subject.
Or human pincushion.
Cimmons wrote about how Leal "rolled up his sleeves" when he and his colleagues were looking for the substance that would lure mosquitoes into a blood meal. "And they found it--nonanal, a substance made by humans and birds that creates a powerful scent that Culex mosquitoes find irresistible."
Leal also recalls the time when he was searching for beetles in Mexico and mosquitoes went after him with a vengeance.
"They'll go through anything, even jeans, as long as they know there is a blood vessel on the other side," Leal told Cimmons. "They can sense the heat."
Indeed, some folks just seem to attract more than their share of mosquitoes.
Only the female mosquitoes bite--they need a blood meal to develop their eggs.
Related links:UC Davis Researchers Identify Dominant Chemical That Attracts Mosquitoes to Humans
Groundbreaking Research on DEET
- Author: Kathy Keatley Garvey
It's a career high.
Three University of California professors were among the 10 inducted as Fellows at the Entomological Society of America's annual meeting held Dec. 13-16 in Indianapolis.
The three are chemical ecologist Walter Leal of UC Davis, and UC Riverside entomologists Brian Federici and Alexander Raikhel.
When you consider that the ESA selects only 10 members--or not more than 10--each year from its 6000-member roster to become Fellows, that's indeed a high honor.
ESA spokesperson Richard Levine says that Fellows are selected for their outstanding contributions in one or more of the following areas: research, teaching, extension, or administration.The accomplishments of Leal, Federici and Raikhel could fill several books.
An insect-net salute to the UC trio!
