That's just one of the facts that UC Davis medical entomologist-geneticist Geoffrey Attardo will discuss when he presents a seminar on "The Mating Biology of Tsetse Flies--Insights into the Morphological, Biochemical, and Molecular Responses to Mating Stimuli in a Viviparous Disease Vector."
The seminar, hosted by the UC Davis Department of Entomology and Nematology, is set for 4:10 p.m., Monday, Oct. 9 in 122 Briggs Hall.
Attardo, an associate professor, UC Davis Department of Entomology and Nematology and chair of the Designated Emphasis in the Biology of Vector-Borne Diseases, is a global expert on vectorborne diseases, including his groundbreaking work on tsetse flies. He researches the invasive yellow mosquito, Aedes aegypti, which can carry such diseases as dengue, chikungunya, Zika and yellow fever.
His work involves predicting insecticide resistance and tracking movements of genetically independent populations of aegypti throughout the state.
"Research into the reproductive behavior of tsetse flies offers key insights into controlling diseases like African sleeping sickness," Attardo writes in his abstract. "Unique among insects, these flies give birth to live offspring. During mating, males transfer a mix of sperm and other vital substances to the females. This study employs state-of-the-art techniques, including 3D scanning and genetic analysis, to monitor changes in the female fly's reproductive system over a 72-hour period post-mating. Findings indicate that mating sets off a chain of intricate changes in the female, affecting everything from biochemistry to gene activity. These changes prepare her for pregnancy and childbirth. The study opens up new avenues for understanding tsetse fly biology and offers potential strategies for disease control."
The seminar also will be on Zoom. The link:
The Attardo lab monitors the dynamics of vector insects at the levels of physiology, population genetics and environmental interactions.
Attardo, who holds a doctorate in genetics from Michigan State University, where he researched the molecular biology of mosquito reproduction, joined the UC Davis Department of Entomology and Nematology in 2017 from the Yale School of Public Health's Department of Epidemiology of Microbial Diseases.
For his outstanding work, he received the 2022 Medical, Urban, and Veterinary Entomology Award from the Pacific Branch, Entomological Society of America, which encompasses 11 Western states, plus parts of Canada and Mexico, and U.S. territories.
For any technical issues regarding Zoom, contact seminar coordinator Brian Johnson at email@example.com.
Enter John Hargrove, director emeritus of the South African Centre for Epidemiological Modelling and Analysis.
He will present a UC Davis Entomology and Nematology seminar on "Tsetse, Trypanosomiasis, and Climate Change: What Can We Learn from Field Data Collected in the Zambezi Valley of Zimbabwe?" at 4:10 p.m. Wednesday, May 3 in 122 Briggs Hall.
His seminar also will be on Zoom:
Host is UC Davis distinguished professor James R. Carey, UC Davis Department of Entomology and Nematology.
Hargrove, associated with the International Clinics on Infectious Disease Dynamics and Data Program (ICI3D), is a faculty member with the Clinic on Meaningful Modeling of Epidemiological Data (MMED) and the Clinic on Dynamical Approaches to Infectious Disease Data (DAIDD). He is a senior research fellow for the South African Centre for Epidemiological Modelling and Analysis, Stellenbosch University, Stellenbosch, South Africa, and a professor emeritus of mathematical sciences at Stellenbosch University.
Hargrove served as the inaugural director of the South African Centre for Epidemiological Modelling and Analysis (SACEMA). The precursors for MMED and DAIDD were launched in 2006 at the beginning of his directorship; he has been involved continuously as an instructor in the program since, according to his biography on ICI3D. Over the past nearly 50 years, Hargrove has combined fieldwork and mathematical epidemiology to understand the population dynamics and control of tsetse flies, the vectors of human African Trypanosomiasis.
He focuses his current research on the modelling population dynamics, with a particular focus on how increasing temperatures in Africa will affect tsetse distribution. This work involves improving estimation of mortality in adult and immature stages of the fly. Since 1999, he has also focused on the analysis and modelling of data in the world of HIV. Current interest are in improving the use of biomarkers for the accurate estimation of HIV incidence.
He holds a bachelor's degree in zoology (1968) from the University of Oxford; a master's degree in biomathematics (1981) from UCLA, and a doctorate in insect physiology (1973) from the University of London.
Department seminar coordinator is urban landscape entomologist Emily Meineke, assistant professor. For technical issues regarding Zoom connections, she may be reached at firstname.lastname@example.org. (See complete list of spring seminars.)
Ah, Saturday, April 17. It's the 107th Annual UC Davis Picnic Day! What's a picnic without bugs?
This year's event, all virtual, is themed "Discovering Silver Linings," and you can do just that by watching the pre-recorded videos and by participating in the Zoom sessions. Check out the Picnic Day schedule of events which include entomological exhibits and talks from the UC Davis Department of Entomology and Nematology, Bohart Museum of Entomology and the UC Davis Graduate Student Association.
New additions to the line-up (featured on the Bohart Museum of Entomology website), involve what you could call "The good, the bad and the bugly." Blue orchard bees, tsetse flies and mosquitoes are spotlighted in UC Davis research-based videos created by KQED's Deep Look series and presented by PBS Digital Studios. Each runs about four minutes.
Here are the KQED productions:
- Watch this Bee Build Her Bee-Jeweled Nest, featuring blue orchard bees, the project of UC Davis doctoral student Clara Stuligross.
- A Tsetse Fly Births One Enormous Milk-Fed Baby, showcasing the work of medical entomologist Geoffrey Attardo, assistant professor, UC Davis Department of Entomology and Nematology.
- This Dangerous Mosquito Lays Her Armored Eggs--in Your House, involving the Aedes aegypti mosquitoes that the Attardo lab studies.
Clara Stuligross, Doctoral Student
They exposed the bees to the neonicotinoid insecticide imidacloprid, widely used in agriculture, and found that the combined threats—imidacloprid exposure and the loss of flowering plants—reduced the bee's reproduction by 57 percent, resulting in fewer female offspring.
Other scientists have conducted similar research on honey bees, but this is the first comparable research on wild bees in field or semi-field conditions. The blue orchard bee, nicknamed BOB, is a dark metallic mason bee, smaller than a honey bee. It is prized for pollinating almond, apple, plum, pear, and peach trees. California almond growers often set up bee boxes or "bee condos" for blue orchard bees to aid in honey bee pollination. In the wild, the bees nest in reeds or natural holes.
Update? "We are currently working on a follow-up study to investigate potential carryover effects of past insecticide exposure on the same bee population, as well as how repeated pesticide exposure over multiple years impacts bee population growth," Stuligross said today.
Geoffrey Attardo, Medical Entomologist-Geneticist
What many people do not know: "Female tsetse flies carry their young in an adapted uterus for the entirety of their immature development and provide their complete nutritional requirements via the synthesis and secretion of a milk like substance," Attardo says.
Attardo led landmark research published Sept. 2, 2019 in the journal Genome Biology that provides new insight into the genomics of the tsetse fly. The researchers compared and analyzed the genomes of six species of tsetse flies. Their research could lead to better insights into disease prevention and control.
The Deep Look episode on mosquitoes, "This Dangerous Mosquito Lays Her Armored Eggs-- in Your House," deals with the ability of Aedes aegypti eggs to survive out of water. Wrote the producers: "The Aedes aegypti mosquito, which can transmit dengue fever and Zika, makes a meal of us around our homes. And her eggs are hardy. They can dry out, but remain alive for months, waiting for a little water so they can hatch into squiggly larvae."
UC Davis medical entomologist-geneticist Geoffrey Attardo, a global authority on tsetse flies, serves as the principal investigator of a research project at the Lawrence Berkeley National Laboratory (Berkeley Lab) that involves scanning the entire reproductive cycle of the fly.
Attardo and other members of the research team are exploring the intact organs and tissues of tsetse flies using a powerful 3D X-ray imaging technique. The study, “Unraveling Intersexual Interactions in Tsetse”), is funded by the National Institute of Allergy and Infectious Diseases (NAIAD) of the National Institutes of Health.
“We started this project in 2019 and the work is ongoing,” said Attardo, an assistant professor in the UC Davis Department of Entomology and Nematology and chair of the Designated Emphasis in the Biology of Vector Borne Diseases. “We actually have scans of flies through the entire reproductive cycle, however, the segmentation is ongoing. We are working on developing ways to train artificial intelligence based software to assist us with the tissue segmentations.”
The tsetse fly transmits the parasite that causes the deadly human and animal trypanosomiasis, better known as African sleeping sickness, says Attardo, who is featured in a recently posted article, "A Detailed Look Inside Tsetse Flies," on the Berkeley Lab website. (See YouTube)
“This specialized reproductive biology has required dramatic modifications to the morphology of the reproductive organs in these and related flies,” according to the Berkeley Lab News Center. “Here, we use phase contrast micro-Computed Tomography (Micro-CT) to visualize these adaptations in three dimensions for the first time. These adaptations include cuticular modifications allowing increased abdominal volume, expanded abdominal and uterine musculature, reduced egg development capacity, structural features of the male seminal secretions and detailed visualization of the gland responsible for synthesis and secretion of “milk” to feed intrauterine larvae. The ability to examine these tissues within the context of the rest of the organ systems in the fly provides new functional insights into how these changes have facilitated the evolution of the mating and reproductive biology of these flies.”
“The imaging technique provided new insights into how the flies' specialized biology governs mating and reproductive processes, including female flies' unique lactation and their delivery of a single fully developed larvae per birthing cycle – whereas most other insect species lay eggs,” according to the article. “The ALS (National Laboratory Advanced Light Source) produces X-rays and other forms of light for a broad range of simultaneous scientific experiments.”
The parasite invades the central nervous system and disrupts the sleep cycle, he says. “If not treated, the disease can result in progressive mental deterioration, coma, systemic organ failure and death.” An estimated 65 million people in 36 countries in sub-Saharan Africa are at risk for the deadly disease, according to the World Health Organization.
Attardo led a study, published in September 2020 in the journal Insects, detailing the ALS imaging work. The article, “Interpreting Morphological Adaptations Associated with Viviparity in the Tsetse Fly Glossina morsitans (Westwood) by Three-Dimensional Analysis,” received widespread attention. ALS experiments allow the researchers to create a detailed 3D visualizatiaon of the reproductive tissues without dissection and staining processes that introduce damage to the delicate samples.
“We want to understand what changes are happening during this process, how the process is being mediated, and if it can be manipulated to artificially repress females in the wild from mating,” Attardo told the Berkeley Lab News Center.
The Berkeley Lab is a multiprogram science lab in the national laboratory system supported by the U.S. Department of Energy through its Office of Science.
In his UC Davis lab, Attardo researches one of 35 tsetse fly species, Glossina morsitans morsitans, which prefers feeding on cattle to humans. Its strong mouthparts can easily puncture the tough cattle hide. In his lab, he feeds them warm cow blood.
As Attardo says on his website: "Arthropod vectored diseases cause more than 1 billion cases of illness and over 1 million deaths in humans each year. My work centers on understanding the reproductive biology of insect vectors of human disease. The goal of this work is to develop a detailed understanding of the molecular biology and physiology of these insects and to exploit this information to control these insects and the diseases they transmit. I use molecular biology and biochemical techniques in my research to address these questions. I also incorporate new technologies such as high throughput DNA sequencing and metabolomics which expand beyond the capabilities of traditional molecular techniques to understand the biology of these organisms at a systems level."
The UC Davis scientist hopes "to use the knowledge gained from these studies to improve current vector control strategies and to develop new strategies that disrupt the reproduction of these disease vectors."
Attardo holds a doctorate in genetics from Michigan State University, where he researched the molecular biology of mosquito reproduction in the lab of Alexander. Prior to joining the UC Davis faculty in 2017, Attardo worked for 13 years in the Department of Epidemiology of Microbial Diseases at the Yale School of Public Health, first as a postdoctoral associate and then as a research scientist studying the reproductive biology of tsetse flies.
In less than 48 hours, nearly 500,000 people have seen them—but not in his restricted-access lab.
His research subjects are blood-sucking tsetse flies, and PBS featured them in its Deep Look video, “A Tsetse Fly Births One Enormous Milk-Fed Baby,” released Jan. 28, and its accompanying news story.
Infected tsetse flies transmit the parasite that causes human and animal trypanosomiasis, better known as sleeping sickness. “The parasite invades the central nervous system and disrupts the sleep cycle,” says Attardo, a global authority on tsetse flies and an assistant professor in the UC Davis Department of Entomology and Nematology. “If not treated, the disease can result in progressive mental deterioration, coma, systemic organ failure and death.”
“PBS sent out a film crew and we spent about two days filming,” he said. The video also includes footage from Africa that PBS purchased, and video of a tsetse trap that Attardo filmed in the Nguruman Escarpment, Kenya, on the border of Tanzania.
Attardo researches one of 35 tsetse fly species, Glossina morsitans morsitans, which prefers feeding on cattle to humans. Its strong mouthparts can easily puncture the tough cattle hide. In his lab, he feeds them warm cow blood.
Tsetse flies, which resemble house flies, are distinguished from other Diptera by unique adaptations, including lactation and the birthing of live young, Attardo says. Just like mammals, tsetse flies, deliver babies and feed them milk. A female produces more than her body weight in milk.
“We mammals like to think we're pretty special, right?” the video begins. “We don't lay eggs. We feed our babies milk. Well, this very pregnant fly is about to prove us wrong. Yep, this tsetse fly is in labor. And that emerging bundle of joy is her larva. While other insects can lay hundreds of eggs, she grows one baby at a time inside her, just like us. Congratulations!”
The accompanying news story, by Gabriela Quirós, explains that Attardo is “trying to understand in detail the unusual way in which these flies reproduce in order to find new ways to combat the disease, which has a crippling effect on a huge swath of Africa.”
The video shows tsetse flies feeding on cattle, at which point the script reader explains that
“Geoff Attardo…hopes to help. He's trying to stop tsetse flies from making babies in the first place. A female only mates once in her life, enough to make the 10 or so babies she'll have. The male makes sure she doesn't mate again by delivering a substance that makes her lose interest in sex. Scientists are trying to figure out what it is. If they could bottle it and spray it, female tsetse flies may never get busy at all. No more tsetse offspring to worry about.”
Attardo says that tsetse flies deliver only one offspring at a time, as compared to insects that lay hundreds or thousands of eggs at one time. Spraying insects and setting traps can reduce the number who develop the disease, but the insects may become resistant to the chemicals.
Once a female mates, storing the sperm she'll birth in a lifetime, the male delivers “a substance that makes her lose interest in sex,” Quirós wrote. It is that substance or what Attarado calls a “reproductive dead end,” that Attardo wants to replicate, to bottle and spray on the tsetse flies..
“The females definitely are making the decisions,” Attardo told Quirós. “She'll sort of tuck her abdomen underneath her body to prevent him from gaining access, and buzz her wings and knock him off.”
The news story also touched on a bacterium, Wigglesworthia glossinidia, found inside the females that apparently has a role in milk production. “When they kill the bacteria with antibiotics, female flies are no longer able to grow a larva, “Queros wrote. “Young larvae stop growing inside their mothers and are aborted. The results of an experiment by Attardo, which he hasn't published yet, suggest that this happens because flies without the bacteria have trouble making milk.”
Last fall, Attardo published landmark research that provides new insight into the genomics of the blood-sucking tsetse fly. The paper, published Sept. 2 in the journal Genome Biology, compares and analyzes the genomes of six species of tsetse flies and the research could lead to better insights into disease prevention and control.
“It was a behemoth project, spanning six to seven years,” said Attardo. “This project represents the combined efforts of a consortium of 56 researchers throughout the United States, Europe, Africa and China.”
Attardo joined the UC Davis Department of Entomology and Nematology in 2017 after 13 years at the Yale University School of Public Health, New Haven, Conn., first as a postdoctoral fellow from 2004 to 2008, and then as associate research scientist and research scientist.
A native of Poughkeepsie, N.Y., he received his bachelor's degree in entomology from the University of Massachusetts, Amherst, in 1994 and his doctorate in genetics from Michigan State University, East Lansing, in 2004.
(Editor's Note: By popular demand, Attardo plans to again show his virtual reality bugs this year at Briggs Hall during the campuswide UC Davis Picnic Day on Saturday, April 18. "We have some new 3D data showing the internal reproductive organs of the tsetse fly that we plan to adapt to virtual reality.")