- Author: Kathy Keatley Garvey
No, it's the mosquito.
Infected mosquitoes transmit diseases that account for some 750,000 deaths a year, according to a recent article in Science Alert.
The mosquito is a piece of work. Remember when several UC Davis scientists were featured in a KQED-produced science video on "How Mosquitoes Use Six Needles to Suck Your Blood?"
So when noted molecular neurobiologist Leslie Vosshall of the Rockefeller University, New York City, speaks on "Neurobiology of the World's Most Dangerous Animal" on Wednesday, May 24 at the University of California, Davis, her audience will not only learn just how dangerous the most dangerous animal is, but learn about her exciting research.
The hourlong seminar, free and open to the public, is set for 4:10 p.m. in the Student Community Center, UC Davis.
The Vosshall laboratory studies the molecular neurobiology of mosquitoes. Female mosquitoes require a blood meal to complete egg development, she explains. "In carrying out this innate behavior, mosquitoes spread dangerous infectious diseases such as malaria, dengue, Zika, Chikungunya and yellow fever."
"Some of the questions we are currently addressing are: Why are some people more attractive to mosquitoes than others? How do insect repellents work? How are multiple sensory cues integrated in the mosquito brain to elicit innate behaviors? How do female mosquitoes select a suitable body of water to lay their eggs? The long-term goal of all of our work is to understand how behaviors emerge from the integration of sensory input with internal physiological states."
The seminar is sponsored by the College of Biological Sciences and the Storer Life Sciences Endowment. Host is molecular geneticist Joanna Chiu, associate professor and vice chair of the UC Davis Department of Entomology and Nematology.
At the Rockefeller University, Vosshall is the Robin Chemers Neustein Professor and head of the Laboratory of Neurogenetics and Behavior and director of the Kavli Neural Systems Institute. She is known for her work on the genetic basis of chemosensory behavior in both insects and humans.
Her notable contributions to science include the discovery of insect odorant receptors, and the clarification of general principles regarding their function, expression and the connectivity of the sensory neurons that express them to primary processing centers in the brain. She founded the Rockefeller University Smell Study in 2004 with the goal of understanding the mechanisms by which odor stimuli are converted to olfatory percepts.
Vosshall received her bachelor's degree in biochemistry from Columbia University, New York, in 1987 and her doctorate from Rockefeller University in 1993. Following postdoctoral work at Columbia University, she joined the Rockefeller faculty in 2000.
She is the recipient of the 2008 Lawrence C. Katz Prize from Duke University, the 2010 DART/NYU Biotechnology Award, and the 2011 Gill Young Investigator Award. She is an elected fellow of the American Association for the Advancement of Science and a member of the National Academy of Sciences.
For more information on the seminar, contact host Joanna Chiu at jcchiu@ucdavis.edu.
- Author: Kathy Keatley Garvey
Mark your calendars for a sobering experience.
The University of California,Davis, will observe World Malaria Day with a daylong retreat showcasing UC Davis scientists’ current research in vector biology and genetics.
The event, free and open to the public, will take place from 9 a.m. to 4 p.m., Monday, April 25 in Room 1102 of the Gourley Clinical Teaching Center, School of Veterinary Medicine, on Garrod Drive.
Malaria is a killer. "Approximately half of the world's population is at risk of malaria, particularly those living in lower-income countries," according to the World Health Organization (WHO). "It infects more than 500 million people per year and kills more than 1 million. The burden of malaria is heaviest in sub-Saharan Africa but the disease also afflicts Asia, Latin America, the Middle East and even parts of Europe."
Postdoctoral researchers Becky Trout (rttrout@ucdavis.edu) and Michelle Sanford (mrsanford@ucdavis.edu) are organizing the event, and issued this statement: “Malaria remains one of the most deadly vectorborne diseases in the world. Worldwide programs continue to rely on control programs based on the most recent research available. In honor of the Roll Back Malaria Program, promoting the education and research in the fight against malaria, student and researchers at UC Davis engaged in vector biology and genetics will come together to discuss their research efforts.”
During the breaks and during lunch, attendees will see a photo slide show of research experiences.
Malaria researchers associated with the UC Davis Department of Entomology include graduate student advisors Anthony “Anton” Cornel, associate professor, Department of Entomology; Shirley Luckhart, professor, Department of Medical Microbiology and Immunology, UC Davis School of Medicine; and Gregory Lanzaro, professor, Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine.
Through their research and public involvement, they're all doing their part to control a killer.
- Author: Kathy Keatley Garvey
Whew, that stinks!
If you've ever smelled a mosquito gravid trap, you know it's not heaven-scent. This isn't about the aroma of summer roses or the whiff of freshly baked cinnamon rolls or the fragrance of vanilla-laced skin cream.
No. This is something that stinks to high heaven. Probably low heaven, too.
It's s-o-o bad (how b-a-d is it?) that you just want to distance yourself from the stench: you hold your nose, mutter “P.U.” and make like a Lightening Bolt (Olympic gold-medal sprinter Usain Bolt).
Said UC Davis chemical ecologist Walter Leal: “It smells like a latrine."
So he and his researchers set out to find a synthetic mixture that attracts mosquitoes but is odorless to humans. And they have. Their mixture, containing the compounds trimethylamine and nonanal in low doses, lures Culex mosquitoes just as effectively as the current gravid trap attractants. But look, ma, no smell!
They did it with what Leal calls "reverse chemical ecology."
The results are published in the current edition of the Public Library of Science Journal or PLOS One.
This research could play a key role in surveillance and control programs for Culex species, which transmit such diseases as West Nile virus, encephalitis and lymphatic filariasis.
What are gravid traps? They're chemical- and water-infused traps, sometimes called oviposition traps or ovitraps. They're meant to attract blood-fed mosquitoes searching for places to lay their eggs. Scientists monitor these traps to determine the presence of West Nile-infected mosquitoes.
“The gravid traps are more important (than carbon-dioxide traps) for surveillance,” Leal said, “as they capture mosquitoes that have had a blood meal and thus, more opportunity to become infected.”
Leal said that another advantage of the gravid traps is that with the capture of one female mosquito, that eliminates not only her, but hundreds of her would-be offspring. “Each female mosquito has the potential to produce about 200 eggs, and she can have as many as five cycles. So when we capture a gravid mosquito, that can remove as many as 500 females.”
Piglets shown by the UC Davis School of Veterinary Medicine are a key attraction at the California State Fair, but bees are drawing a lot of attention, too. (Photo by Kathy Keatley Garvey)The compounds used in the research, Leal said, are “simple and inexpensive” and would be of great benefit “to not only us but third-world countries where Culex quinquefasciatus is a problem.” Piglets shown by the UC Davis School of Veterinary Medicine are a key attraction at the California State Fair, but bees are drawing a lot of attention, too. (Photo by Kathy Keatley Garvey)The researchers did preliminary field testing in Davis and Sacramento but when aerial sprays mitigated the levels of West Nile virus-infested mosquitoes, they set up traps in Recife, Brazil, a city endemic for lymphatic filariasis. Leal is a native of Brazil.
Other scientists involved in the study included UC Davis researchers Wei Xu, Yuko Ishida, Zain Syed, Nicolas Latte, Angela Chen and Tania Morgan; associate professor Anthony Cornel, associate professor of entomology at UC Davis and director of the Mosquito Control Research Laboratory, based at the Kearney Agricultural Center, Parlier; and Rosângela M. R. Barbosa and André Furtado of the Department of Entomology, Centro de Pesquisas Ageu Magalhaes-Fiocruz, Recife, Brazil.
Piglets shown by the UC Davis School of Veterinary Medicine are a key attraction at the California State Fair, but bees are drawing a lot of attention, too. (Photo by Kathy Keatley Garvey)(See more information on the UC Davis Department of Entomology Web site).
- Author: Kathy Keatley Garvey
We know it works, but how?
Just how does DEET work? Does it jam the senses of a mosquito? Does it mask the smell of the host?
You spray the chemical repellent on your arm and thankfully, those darn skeeters leave you alone. They need a blood meal to develop their eggs, so off they buzz to find another host, one that's not so inhospitable.
But why do mosquitoes avoid DEET?
Well, they avoid it because it smells bad to them. Yes, they can smell it--that's why they avoid it.
The groundbreaking research, the work of UC Davis chemical ecologist Walter Leal and researcher Zain Syed, is published today in the Proceedings of the National Academy of Sciences (PNAS), which lifted the news embargo at 2 p.m., Pacific Standard Time.
The research contradicts a Science article published in March by researchers at Rockefeller University, New York. The researchers, as other scientists have long believed, said mosquitoes can't smell DEET because it jams the odorant receptors in insect nervous systems.
The Leal-Syed research solidly establishes the real mode of action.
Noted entomologist James "Jim" Miller of Michigan State University praised the Leal-Syed work as correcting “long-standing erroneous dogma.”
Said Miller: "For decades we were told that DEET warded off mosquito bites because it blocked insect response to lactic acid from the host -- the key stimulus for blood-feeding. Dr. Leal and co-workers escaped the key stimulus over-simplification to show that mosquito responses -- like our own -- result from a balancing of various positive and negative factors, all impinging on a tiny brain more capable than most people think of sophisticated decision-making.”
“This new work corrects long-standing erroneous dogma, and shows that recent work on DEET mode-of-action published in the flagship journal, Science, apparently was flat-out wrong,” Miller said. “One of the great attributes of science is that, over time, it is self-correcting."
Leal, past president of the International Society of Chemical Ecology and former chair of the UC Davis Department of Entomology, said previous findings of other scientists showed a “false positive” resulting from the experimental design.
Now that we know that skeeters can smell it, this will no doubt lead to better methods of insect control. Or, as Major Dhillon, president of the American Mosquito Control Association and district manager of the Northwest Mosquito and Vector Control District, Riverside, said: ”In the future, this new knowledge can be incorporated into developing new repellents and may be in control strategies for Culex quinquefasciatus and other mosquitoes.”
Those darn female mosquitoes, always in a “Let-us-prey” mood, have clearly met their match: the "why" behind "Let us spray."
- Author: Kathy Keatley Garvey
I've always loved the wit and wisdom of insect-inspired poets.
God in His wisdom made the fly
And then forgot to tell us why.
- - Ogden Nash "The Fly"
We hope that, when the insects take over the world, they will remember with gratitude how we took them along on all our picnics.
- - Richard Vaughan
If you look at the world through a viewfinder--as I have a habit of doing--it's a wonderful, exquisite place, especially if you capture critters in their natural habitat. They don't complain when you make them look fat, skinny, nice or ferocious.
Blow flies, honey bees, carpenter bees, spotted cucumber bees, the ten-lined June beetle, and mosquitoes all appear in my viewfinder. Okay, I know. We're not supposed to like some of these pests (such as the carpenter bees, spotted cucumber bees and the ten-lined June beetles), but hey, all of them are pretty enough to sing the national anthem at the Olympics.
Photography, or writing with light, is just that. Writing with light. Back before the digital technology age, we used to process film, make prints and then hang them out to dry. We "pho-togs" marinated ourselves in Dektol, DK-60 and Hypo.
Our "pheromone" wasn't always appreciated. But the images were.
Bees are black, with gilt surcingles,
Buccaneers of buzz.
- - Emily Dickinson
The mosquito is the state bird of New Jersey.
- - Andy Warhol
