- Author: Kathy Keatley Garvey
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.
- Author: Kathy Keatley Garvey
So do honey bees.
“Honey bees exhibit complex social behavior that rivals our own,” internationally recognized honey bee geneticist Robert E. Page Jr., recipient of the 2019 UC Davis Distinguished Emeritus Professor Award told the crowd at his BrainFood Seminar Nov. 14 in the Walter A. Buehler Alumni Center.
Speaking on “The Social Contract: How Complex Social Behavior Evolve," Page said that it is "fundamentally bound within a social contract much like ours that makes the basic social structure inescapable, a consequence of living together in family groups. Social structures evolve by natural selection operating on the final product, the colony as a reproductive unit. The structures themselves are reverse engineered.”
In his talk, Page showed how selection on the economy of the colony shapes structures from nest and social architecture to gene networks. UC Davis Emeriti Association and the UC Davis Retirees' Association sponsored the program.
"It is likely that this was the first talk ever to link the U.S. Constitution's 'We the People' to the theory of social evolution in insects," said colleague UC Davis distinguished professor James R. Carey of the Department of Entomology and Nematology.
Page is known for his research on honey bee behavior and population genetics, particularly the evolution of complex social behavior. One of his most salient contributions to science was to construct the first genomic map of the honey bee, which sparked a variety of pioneering contributions not only to insect biology but to genetics at large.
Page is not only a UC Davis Distinguished Emeritus Professor, but a Arizona State University (ASU) Regents Professor Emeritus and ASU University Provost Emeritus. Page chaired the Department of Entomology from 1999 to 2004, when Arizona State University recruited him to be the founding director of the School of Life Sciences of Arizona State University (ASU). His ASU career advanced to dean of Life Sciences; vice provost and dean of the College of Liberal Arts and Sciences; and university provost.
Born and reared in Bakersfield, Kern County, Rob received his bachelor's degree in entomology, with a minor in chemistry, from San Jose State University in 1976. After obtaining his doctorate from UC Davis in 1980, he served as assistant professor at The Ohio State University before joining the UC Davis entomology faculty in 1989 as an associate professor. He began working closely with Harry H. Laidlaw Jr., (the father of honey bee genetics) for whom the university's bee facility is named. Together they published many significant research papers.
At UC Davis, he maintained a honey bee-breeding program for 24 years, from 1989 to 2015, managed by bee breeder-geneticist Kim Fondrk at the Harry H. Laidlaw Jr. Honey Bee Research Facility. They discovered a link between social behavior and maternal traits in bees. Their work was featured in a cover story in the journal Nature. In all, Nature featured his work on four covers from work mostly done at UC Davis.
Page and his lab pioneered the use of modern techniques to study the genetic basis of social behavior evolution in honey bees and other social insects. He was the first to employ molecular markers to study polyandry and patterns of sperm use in honey bees. He provided the first quantitative demonstration of low genetic relatedness in a highly eusocial species.
His work has garnered a significant impact in the scientific community through his research on the evolutionary genetics and social behavior of honey bees. He was the first to demonstrate that a significant amount of observed behavioral variation among honey bee workers is due to genotypic variation. In the 1990s, he and his students and colleagues isolated, characterized and validated the complementary sex determination gene of the honey bee; considered the most important paper yet published about the genetics of Hymenoptera. The journal Cell featured their work on its cover. In subsequent studies, he and his team published further research into the regulation of honey bee foraging, defensive and alarm behavior.
Page has authored than 250 research papers, including five books: among them “The Spirit of the Hive: The Mechanisms of Social Evolution,” published by Harvard University Press in 2013. He is a highly cited author on such topics as Africanized bees, genetics and evolution of social organization, sex determination, and division of labor in insect societies. His resume shows more than 18,000 citations.
Highly honored by his peers, Page is a fellow of a number of organizations, including the American Association for the Advancement of Science, the California Academy of Sciences, the Entomological Society of America, and organizations in Germany and Brazil. He received the Alexander von Humboldt Senior Scientist Award, known at the Humboldt Prize, the highest honor given by the German government to foreign scientists. He received the 2018 Thomas and Nina Leigh Distinguished Alumni Award from UC Davis Department of Entomology and Nematology.
Page is the second bee specialist from the Department of Entomology to receive the prestigious Distinguished Emeritus Professor award. Native pollinator specialist Robbin Thorp (1933-2019) received the UC Davis Distinguished Emeritus Professor Award in 2015. A global authority on bees known for his research, teaching, mentoring and public service, Thorp co-authored Bumble Bees of California: An Identification Guide (2014, Princeton University Press) and California Bees and Blooms: A Guide for Gardeners and Naturalists (2014, Heyday Books).
- Author: Kathy Keatley Garvey
But if you're UC Davis entomologist-geneticist Geoffrey Attardo, you do.
He led landmark research published Sept. 2 in the journal Genome Biology that provides new insight into the genomics of the tsetse fly, an insect that transmits the parasite that causes human and animal trypanosomiasis. In humans, it's commonly known as sleeping sickness, and if not treated, it's fatal.
Tsetse flies, Glossina sp., are of great medical and economic importance, wrote Attardo and co-authors Adly M. M. Abd-Alla of the Insect Pest Control Laboratory, Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria, and Serap Aksoy of the Yale School of Public Health, New Haven, Conn. They related that since the implementation of surveillance and record-keeping in the 20th century, “millions of people in sub-Saharan Africa” have died from sleeping sickness.
Their research compares and analyzes the genomes of six species of tsetse flies and could lead to better insights into disease prevention and control. “It was a behemoth project, spanning six to seven years,” said Attardo, an assistant professor in the Department of Entomology and Nematology. “This project represents the combined efforts of a consortium of 56 researchers throughout the United States, Europe, Africa and China.”
“The aim of these studies,” the authors wrote, “was to generate and mine the genomic sequences of six species of tsetse flies with different ecological niches, host preferences, and vectorial capacities. The goals of the analyses performed here are to identify the novel genetic features specific to tsetse flies and to characterize the differences between the Glossina species to correlate the genetic changes with phenotypic differences in these divergent species.”
“Expanded genomic discoveries reveal the genetics underlying Glossina biology and provide a rich body of knowledge for basic science and disease control,” the scientists concluded. “They also provide insight into the evolutionary biology underlying novel adaptations and are relevant to applied aspects of vector control such as trap design and discovery of novel pest and disease control strategies.”
Attardo, who joined the UC Davis faculty in 2017 after serving 13 years with the Yale School of Public Health, said the massive research project involved “the complete sequencing and assembly of six Glossina species, including the two primary vectors of human African tryapnosomiasis, three major vectors of animal trypanosomiasis and one ancestral tsetse species which demonstrates some resistance to the species of trypanosomes responsible for human and some animal forms of the disease.”
- A clearer definition of the Glossina phylogenetic tree and placement of a controversial species.
- Identification of rapidly evolving regions of the tsetse genome relative to Drosophila.
- Identification of Glossina specific genes and their functions as well as expansions and contractions of gene families in tsetse relative to other flies.
“We discuss the functional implications of these changes and how they relate to tsetses' physiological adaptations and evolutionary history,” Attardo noted.
“We discovered that the rhodopsin gene family which is associated with vision/color detection shows conservation in motion detection and tracking associated genes.” Attardo said. “However, the gene coding for the protein that detects blue wavelengths is divergent relative to houseflies and shows the highest variance between Glossina species of all the rhodopsin genes. This is significant as the color blue is used as an attractant to bring tsetse into the traps used for control. It suggests that different species may be tuned/attracted to different wavelengths of blue.”
They also analyzed the genes associated with tsetse immunity and the relative differences in comparison with houseflies and fruit flies. “We see many immune genes missing in Glossina and increased copy numbers of genes associated with negative regulation of immune function. We think this may be associated with the evolution of obligate symbiosis as a way to protect their symbionts.”
“We also found extreme conservation of milk proteins between all sequenced species,” the UC Davis medical entomologist said. “On the flip side, male reproductive proteins (seminal proteins) appear to be very rapidly evolving relative to the rest of the genome. The copy numbers of these genes also change significantly between species.”
The scientists also found an overall reduction of olfactory associated genes and protein modifications specific to salivary proteins in the two species that vector human trypanosomiasis.
In 1995, the World Health Organization (WHO) estimated that 60 million people were at risk of sleeping sickness, with an estimated 300,000 new cases per year in Africa, and fewer than 30,000 cases diagnosed and treated. Due to increased control, only 3796 cases were reported in 2014, with less than 15,000 estimated cases, according to WHO statistics.
The parasitic disease “mostly affects poor populations living in remote rural areas of Africa,” according to WHO. “Untreated, it is usually fatal. Travelers also risk becoming infected if they venture through regions where the insect is common. Generally, the disease is not found in urban areas, although cases have been reported in suburban areas of big cities in some disease endemic countries.”
Several National Institutes of Health (NIH) grants, awarded to Attardo and Aksoy, funded the research. They also drew funding from the McDonnell Genome Institute at Washington University School of Medicine; the National Research Foundation, the Swiss National Science Foundation, and the Slovak Research and Development Agency.
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- Author: Kathy Keatley Garvey
It's August, 2007 and bee breeder-geneticist Susan Cobey, manager of the Harry H. Laidlaw Jr. Honey Bee Research Facility, University of California, Davis, is opening a hive in the apiary.
"Girls, where's your mother?” she asks again, pulling out another frame.
She quickly locates the queen bee, "the mother of them all." And "all" is not right in the bee world.
Susan "Sue" Cobey wants to "build a better bee."
Cobey, now a bee breeder-geneticist at Washington State University, seeks to maximize the good traits and minimize the bad traits. By controlling the genetics of honey bees (Apis mellifera), she says, researchers can breed stronger, more survivable bees--bees able to withstand such pests as varroa mites and such maladies as colony collapse disorder. “Controlled mating is the basic foundation of all stock improvement programs.”
Cobey who joined Washington State University's Department of Entomology in 2010, works with department chair and bee scientist Walter "Steve" Sheppard, who researches population genetics and evolution of honey bees, insect introductions and mechanisms of genetic differentiation; and bee scientist Brandon Hopkins, an expert on cryopreservation of bee semen.
"Building a better bee” involves collecting bee semen (germplasm) in European countries, including Italy, Slovenia, Germany, and the Republic of Kazakhstan. Those countries, she points out, rear bees with favorable genetic traits, such as resistance to varroa mites, the No. 1 enemy of beekeepers in the United States.
The dwindling gene pool diversity in the United States is troublesome, Cobey says. Although European colonists brought honey bees to the Jamestown colony in 1622, live honey bee imports have been banned in the United States since 1922.
So Cobey has been traveling to Europe since 2006--every year but 2016--to collect bee semen. “It took me 22 years to get that first permit," says Cobey. "It was opening the Canadian border to Europe that turned it--politics, not biology-based. We started asking (to collect bee semen in Europe) in the early 1980s with Harry Laidlaw's backing."
"My first trip to Europe was in 2006 from Ohio State University for carnica (Apis mellifera carnica, a darker subspecies) bee stock," recalled Cobey, who studied and trained with Harry Laidlaw, the father of honey bee genetics. Cobey joined the UC Davis Department of Entomology in 2007 and a year later, she began collecting bee semen in Europe with Steve Sheppard. The WSU bee breeding program involves crossbreeding honey bees to bolster their genetic traits. WSU is the only lab in the country with permits to import bee semen, and the only laboratory with the ability to freeze it. The WSU team uses liquid nitrogen to preserve the bee semen.
The European trip was memorable and productive. "Slovenia is a beautiful country with a long tradition of beekeeping," Cobey said.
"In Semič, Slovenia, we collected bee semen, met with the local beekeepers and gave presentations about our program,” Cobey said. “Afterwards we celebrated with a feast of roasted pig, hosted by Stane Plut."
"What a trip that was (to Italy and Slovenia)!" said Park-Burris. "Slovenia only allows the beekeepers to keep Carniolan bees. Sue was in heaven and it was fun to see how excited she got about her bees. Likewise I was really happy to see the Italy stock in Bologna again. The beekeepers there were so excited that we wanted more of their stock. Their hospitality was overwhelming."
Park-Burris marveled that the Slovenians keep almost all of their hives in "houses" and "then they paint pictures on them that tell a story. It was very interesting. One Slovenian told me that they treat their bees like pets and that was so true!"
Cobey is an international authority on the instrumental insemination of queen bees. She's taught the specialized technique for more than three decades, instructing students how to extract semen from a drone, and inseminate an anesthetized virgin queen. Magnified images on a computer screen help illustrate the procedure.
Cobey began training students in instrumental insemination in 1984. "This has taken me all over the world--currently I have invitations/inquiries to six countries," said Cobey, who has set up a lab at her home on Whidbey Island to teach workshops. Husband Timothy Lawrence, also a veteran beekeeper, is an associate professor and the county director (Island County) of Washington State University Extension.
"I receive three to five requests for classes per day here; I'm sorting these to the most needed/most serious," Cobey said. "The interest is much more serious. But note--still many struggle with this, as there are many aspects, including the specialized beekeeping that goes with it."
Cobey recently taught UC Davis staff research associates and beekeepers Bernardo Niño and Charley Nye of the Elina Lastro Niño lab in a three-day class in her lab. "I'm just doing small classes so I can give more individual attention, and concentrate on the details. So I have just three or four people per class. I hope UC Davis starts some classes as the interest is overwhelming." A UC Davis goal is to offer classes in 2018 or 2019, according to Niño.
Some of Cobey's students go on to teach others the technique. UC Davis graduate Elizabeth Frost learned from Susan Cobey while working as her staff research associate at the Laidlaw facility. "She is now teaching instrumental insemination in Australia," Cobey said.
Cobey traces her interest in bees back to the 1970s. After enrolling in a student exchange program in entomology in 1975 at Oregon State University, Corvallis, she received her bachelor's degree in entomology in 1976 from the University of Delaware, Newark. From 1978 to 1980, she worked at UC Davis, where she was influenced by Harry Laidlaw (1907-2003).
Laidlaw perfected artificial bee insemination technology. “He discovered the valve fold in the queen bee which hinders injection of semen into the lateral oviducts,” Cobey said. “He developed instrumentation to bypass the valve fold enabling the success of bee insemination.”
Utilizing the training, Cobey established the Vaca Valley Apiaries in Vacaville in 1982, developing the highly regarded New World Carniolan Breeding Program. The Carniolans, originally from the Austrian Alps and the Balkans, are darker than the popular Italian honey bees, the most common subspecies in the United States. The Carniolans are known for their gentle behavior, and may be more suited to cooler weather.
In 1990 Cobey pulled up roots—and hives—and settled in Ohio, serving as staff apiarist at the Rothenbuhler Honey Bee Research Laboratory at Ohio State University until accepting the staff research associate position and manager of the UC Davis facility in 2007.
Now she's focused on the WSU bee breeding program, which produces breeder queen bees, which are then provided to commercial queen bee producers, who in turn can produce thousands of queen bees for the nation's beekeepers. The goal is to preserve and improve the stock of honeybees and to prevent subspecies from extinction.
Hopkins says that genetic diversity offers improved bee fitness and productivity. A genetically diverse colony handles diseases better. The biggest need in the U.S. honey bee population is anything that would increase resistance to parasitic Varroa mites, Hopkins says. (See WSU post.)
Cobey is featured in a National Public Radio piece, "No Offense, American Bees, But Your Sperm Isn't Cutting It."
"Honey bees aren't native to America," Cobey told reporter Ryan Bell. "We brought them here. But the U.S. closed its borders to live honey bee imports in 1922, and our honey bee population has been interbreeding ever since."
"Girls, where's your mother?"
