- Author: Kathy Keatley Garvey
His topic is""Do Positive Species Interactions Promote Invasions? The Role of Ant-Hemipteran Mutualisms in Ant Invasions." The seminar takes place from 12:10 to 1 p.m. in 122 Briggs. Host is assistant professor Brian Johnson, who coordinates the winter quarter seminars. Plans call for video-recording the seminar for later posting on UCTV.
"Mutualistic and facilitative interactions encourage the establishment and spread of introduced species to a degree that is currently underappreciated," said Holway in his abstract. "Commonly formed mutualistic associations between introduced ants and honeydew-producing Hemiptera alter the abundance and behavior of these ants in ways that directly contribute to their ecological success. Our research centers on the red imported fire ant (Solenopsis invicta) and the Argentine ant (Linepithema humile), the two most widespread, abundant and ecologically damaging introduced ants in North America"
"As with most interactions between ants and honeydew-producing Hemiptera, partnerships that involve either S. invicta or L. humile tend to be general, with the ants commonly and opportunistically forming associations with a wide variety of aphids, scales, and mealybugs (including both native and non-native species). Using a combination of experimental approaches and isotopic analyses, our research demonstrates that assimilation of carbohydrate-rich resources (e.g., honeydew, nectar) elevates levels of colony growth and affects worker behavioral traits in ways that likely contribute to competitive performance."
"Intense interspecific competition in their native Argentina constrains the ability of S. invicta and L. humile to control honeydew-producing Hemiptera (and other accessible sources of carbohydrates), whereas these invaders dominate these resources in their introduced US range. Consistent with this strong pattern, nitrogen isotopic data reveal that S. invicta and L. humile from populations in the US occupy a lower trophic position compared to that occupied by these species in Argentina. Given the high densities often achieved by introduced ants, their interactions with honeydew-producing insects may represent an important and largely underappreciated form of herbivory."
Holway advanced to professor in the Division of Biological Sciences at UC San Diego in 2011. He has served as director of the UC San Diego Natural Reserve System since 2010.
He is the author of more than 60 peer-reviewed publications, including research in Ecological Entomology, Oecologia, Proceedings of the National Academy of Sciences, Ecology, Insectes Sociaux, Molecular Ecology, and Journal of Experimental Biology. Among the most recent:
LeVan, K.E., K-L.J.Hung, K.R. McCann, J. Ludka & D.A. Holway. Floral visitation by the Argentine ant reduces pollinator visitation and seed set in the coast barrel cactus, Ferocactus viridescens. Oecologia, In press.
Yoo, H.J., M.C. Kizner & D.A. Holway. Ecological effects of multi-species, ant-hemipteran mutualisms in citrus. Ecological Entomology 38:505-514.
Wilder, S.M., T.R. Barnum, D.A. Holway, A.V. Suarez & M.D. Eubanks. 2013. Introduced fire ants can exclude native ants from critical mutualist-provided resources. Oecologia 172:197-205.
Wilder, S.M., D.A. Holway, A.V. Suarez, E.G. LeBrun & M.D. Eubanks. 2011. Intercontinental differences in resource use reveal the importance of mutualisms in fire ant invasions. Proceedings of the National Academy of Sciences 108:20639-20644.
Yoo, H.J. & D.A. Holway. 2011. Context-dependence in an ant-aphid mutualism: direct effects of tending intensity on aphid performance. Ecological Entomology 36:450-458.
Wilder, S.M., D.A. Holway, A.V. Suarez & M.D. Eubanks. 2011. Macronutrient content of plant-based food affects growth of a carnivorous arthropod. Ecology 92:325-332.
LeBrun, E.G., M. Moffett & D.A. Holway. 2011. Convergent evolution of levee building behavior among distantly related ant species in a flood-plain ant assemblage. Insectes Sociaux 58:263-269.
Wilson, E.E. & D.A. Holway. 2010. Multiple mechanisms underlie displacement of solitary Hawaiian Hymenoptera by an invasive social wasp. Ecology 91:3294-3302.
Wilson, E.E, C. Sidhu, K.E. LeVan & D.A. Holway. 2010. Pollen foraging behavior of solitary Hawaiian bees revealed through molecular pollen analysis. Molecular Ecology 19: 4823-4829.
Menke,S.B., A.V. Suarez, C.V. Tillberg, C.T. Chou & D.A. Holway. 2010. Trophic ecology of the invasive Argentine ant: spatio-temporal variation in resource assimilation. Oecologia 164:763-773.
Wilson, E.E., C.V. Young & D.A. Holway. 2010. Predation or scavenging? Thoracic muscle pH and rates of water loss reveal cause of death in arthropods. Journal of Experimental Biology 213:2640-2646.
Kay, A.D., T. Zumbusch, J.L. Heinen, T.C. Marsh, & D.A. Holway. 2010. Nutrition and interference competition have interactive effects on the behavior and performance of Argentine ants. Ecology 91:57-64.
- Author: Kathy Keatley Garvey
His seminar is from 12:10 to 1 p.m. in 122 Briggs Hall. Host is Michael Parrella, professor and chair of the department.
Gillespie's abstract: "The phenomenon of global climate change (GCC) is likely to have a dominant impact on agriculture, food supply and food security in the coming decades. The two dominant GCC trends – increased carbon dioxide concentrations, and increased average annual temperatures, will cause changes in how and where crop plants grow. However, because arthropods are mostly cold-blooded, the underlying effect of GCC on average temperature and temperature ranges within growing seasons is likely to be of greater importance for IPM in agriculture. Biological control of pest insects by arthropod natural enemies is an integral part of IPM. The benefits derived from biological control (increased yields and reduced pest numbers) are governed by the principles of population and community ecology. Relationships between species in biological control, such as prey-predator dynamics, competition and trophic cascades are driven in part by rates of growth and movement of the component species, which are in turn governed in part by temperature."
"This seminar presentation will summarize some recent work on the effects of extreme temperatures on an experimental biological control community. I will conclude by presenting some preliminary results from work-in-progress which places the effects of extreme temperatures in the context of the two key GCC trends: carbon dioxide and average growing season temperature."
Gillespie says he's primarily an insect ecologist and biological control scientist. "For over 30 years the focus of my research has been the development and introduction of biological control agents and biological control systems for use in Canadian greenhouse crops. Many of the predators and parasitoids that I have developed as biological control agents are currently produced and sold in Canada, and are used extensively to replace insecticide use in greenhouse and other crops. The principles of population and community ecology are used to develop approaches to limit insect population growth in order to reduce or eliminate insecticide applications while maintaining productivity, crop quality and profitability. The results help to develop IPM systems in crops, and improve worker and environmental health."
His current research projects entail classical biological control programs for pests of canola and other cole crops; development of life table models for spotted wing drosophila; surveys of egg parasitoids of Pentatomidae; and development of an improved understanding of the effects of extreme temperature events and other climate change factors biological control communities. This last work led to participation in a report on the effects of climate change on invertebrate genetic resources in Agriculture for the FAO."
Gillespie also is an adjunct professor in the Department of Biological Sciences at Simon Fraser University where he has co-supervised numerous master's degree and Ph.D. students. He served on supervisory committees for M.Sc. and Ph.D. students at Cornell University, University of British Columbia, and the University of Windsor. His contributions have been recognized by an honorary membership in the International Organization for Biological Control (2012), an AAFC Gold Harvest Award (2011), by a lifetime achievement award from the Professional Pest Management Association of British Columbia (2011), and an Award of Excellence from Association of Natural Biological Control Producers (2003)
Assistant professor Brian Johnson is coordinating the winter quarter seminars. Plans call for recording the seminars for later posting on UCTV.
- Author: Kathy Keatley Garvey
Would you snuggle with a tick?
Would you snuggle with lice?
Shades of Dr. Seuss?
No, “Snuggle Bugs” is the theme of the Bohart Museum of Entomology’s open house on Sunday, Jan. 12.
The event, free and open to the public, will be held from 1 to 4 p.m. in the Bohart Museum, located in Room 1124 of the Academic Surge building on Crocker Lane (formerly California Drive), UC Davis campus.
Visitors can learn about ticks, bed bugs, lice, mites, fleas and mosquitoes--the kind of bugs people don’t want to snuggle with, said Tabatha Yang, education and outreach coordinator.
A special attraction will be the bed bug colony being reared by Danielle Wishon, a UC Davis entomology graduate and an affiliate of the Bohart Museum. She began rearing the colony in October 2012.
“Aside from the fact that I find them visually adorable, I am interested in the current public panic over their current increase in population around the United States," she said prior to a "bed bug feeding" at another Bohart open house. "The idea that several little animals will crawl up to you while you sleep and feed on your blood really disturbs most people, despite the fact that they do not transmit any disease."
Wishon, now an employee of the California Department of Food and Agriculture, is a past president of the UC Davis Entomology Club and recipient of the department’s 2011 Outstanding Undergraduate Student Award.
"I think the general public would be very interested to see them feeding," she said. "There is a lot of misinformation on the Internet about them, so it would also be a good opportunity for Q and A."
The Bohart Museum, directed by Lynn Kimsey, professor of entomology at UC Davis and housing nearly eight million specimens, is the seventh largest insect collection in North America. It is also the home of the California Insect Survey, a storehouse of insect biodiversity. Noted entomologist Richard M. Bohart (1913-2007) founded the museum in 1946.
Special attractions at the Bohart include a live "petting zoo," with critters such as Madagascar hissing cockroaches, walking sticks, millipedes, tarantulas and praying mantids. Visitors can also shop at the year-around gift shop (or online) for t-shirts, jewelry, insect nets, posters and books, including the newly published children’s book, “The Story of the Dogface Butterfly,” written by UC Davis doctoral candidate Fran Keller and illustrated (watercolor and ink) by Laine Bauer, a 2012 graduate of UC Davis. The 35-page book, geared toward kindergarteners through sixth graders, also includes photos by naturalist Greg Kareofelas of Davis, a volunteer at the Bohart.
Bohart officials schedule weekend open houses throughout the academic year. Regular hours are from 9 a.m. to noon and from 1 to 5 p.m., Monday through Thursday. The insect museum is closed to the public on Fridays and on major holidays. Admission is free. More information is available from Tabatha Yang at tabyang@ucdavis.edu.
- Author: Kathy Keatley Garvey
Murphy, a fourth-year UC Davis student majoring in neurobiology, physiology, and behavior, received $1563 to study “Codon Optimization: Cracking the Genetic Code.” A codon is a unit of three nucleotides that together codes for an amino acid, the building block of proteins in all organisms. Using the fly, Drosophila melanogaster, as a model system, Murphy is exploring the functional significance of codon bias, a phenomenon in which certain codons are favored over others even though they may code for the same amino acid.
Murphy has worked in the Chiu lab since 2011. “Katie is one of the most talented and hardworking student I have ever encountered,” Chiu said. “I can't think of anyone else who is more deserving of this award.”
Murphy is one of a select group of students in the Research Scholars Program in Insect Biology, organized and directed by professor Jay Rosenheim and assistant professors Louie Yang and Joanna Chiu. The program aims to provide undergraduates with a closely mentored research experience in biology.
The Provost's Undergraduate Fellowship supports undergraduate students doing research or creative projects under the guidance of UC Davis faculty members. Students from all discipline areas are eligible to apply
As a Provost fellow, Murphy will present her work at the annual UC Davis Undergraduate Research Conference, which takes place April 25–26 in Freeborn Hall.
In 2012, Murphy received a UC President's Undergraduate Research Fellowship for her research on "Transgenic Yeast as an Organic Pesticide," exploring the use of RNAi technology in combating the invasive pest, the spotted-wing Drosophila suzukii. She also received a 2013 McBeth Memorial Scholarship and a 2010 Voorhies Memorial Scholarship.
Murphy is a 2010 graduate of Kelseyville High School (Lake County) and valedictorian of her class.
“My favorite subject in high school was biology,” she recalled. “My favorite project was when we dissected a cat in anatomy. In college, I lucked into a lab job where my boss and co-workers were willing to teach me and allowed me the freedom to take on my own projects, an opportunity that few undergrads get.”
Following graduation, she plans to travel and continue her current research projects.
- Author: Kathy Keatley Garvey
The research, “Gradual Molecular Evolution of a Sex Determination Switch in Honeybees through Incomplete Penetrance of Femaleness,” is published in the December edition of Current Biology. The research shows that five amino acid differences separate males from females.
The lead author, Martin Beye, an evolutionary geneticist at the University of Duesseldorf, Germany, was Page’s former UC Davis postdoctoral researcher. Bee breeder-geneticist Michael “Kim” Fondrk provided the genetic material from crosses using Page’s bees that he tends at the Harry H. Laidlaw Jr. Honey Bee Research Facility, UC Davis.
“The story goes back to Johann Dzierson in the mid 1800s through Mendel, through Harry Laidlaw to me and to my former postdoc at Davis, Martin Beye,” Page said.
“Much of the work was done at UC Davis beginning in 1990,” Page said. "From 1999-2000, Martin Beye was a Fyodor Lynen Fellow in my lab funded by the Alexander von Humboldt Foundation. During that year he began the sequencing and characterization of the csd gene; the paper was eventually published as a cover article in Cell."
Said Fondrk: “This project was a long time in making; it began soon after our Cell paper was published in 2003. First we needed to assemble variation for alleles at the sex locus, by collecting drones from many different, presumably unrelated queens, and mating one drone each through an independently reared set of queens using instrumental insemination (which was Fondrk's task). "Then a second set of crosses was made to identify and isolate individual sex alleles. The progeny that resulted from this cross were taken to Germany where Martin Beye’s team began the monumental task of sequencing the sex determination region in the collected samples.”
Silesian monk Johann Dzierson began studying the first genetic mechanism for sex determination in the mid-1800s. Dzierson knew that royal jelly determines whether the females will be queen bees or honey bee colonies, but he wondered about the males.
Dzierson believed that the males or drones were haploid – possessing one set of chromosomes, a belief confirmed in the 1900s with the advent of the microscope. In other words, the males, unlike the females, came from unfertilized eggs.
“However, how this system of haplodiploid sex determination ultimately evolved at a molecular level has remained one of the most important questions in developmental genetics,” Coulombe pointed out in her news release.
The collaborators resolved the last piece of the puzzle.
“Once again, the studies by Dr. Rob Page and his colleagues have unraveled another mystery of honey bee development,” commented Extension apiculturist Eric Mussen of the UC Davis Department of Entomology and Nematology, who was not involved in the study but knows the work of many of the collaborators. “It would be interesting if someone investigated the same type of sexual dimorphism in other hymenopterans to determine if they all use the same, ancient-based mechanism.”
The authors studied 14 natural sequence variants of the complementary sex determining switch (csd gene), for 76 genotypes of honey bees.
“However, the questions of which alleles were key, how they worked together and in what combinations and why this system evolved were left unanswered, though tantalizing close. This compelled the current team of collaborators to step back to review what actually constitutes an allele.”
Page was quoted in the news release: “There has to be some segment of that gene that is responsible in this allelic series, where if you have two different coding sequences in that part of the gene you end up producing a female. So we asked how different do two alleles have to be? Can you be off one or two base pairs or does it always have to be the same set of sequences? We came up with a strategy to go in and look at these 18-20 alleles and find out what regions of these genes are responsible among these variants.”
“In this process,” Page said, “we also had to determine if there are intermediate kinds of alleles and discover how they might have evolved.”
“What the authors found,” wrote Coulombe, “was that at least five amino acid differences can control allelic differences to create femaleness through the complementary sex determiner (csd) gene – the control switch.”
Page explained: “We discovered that different amounts of arginine, serine and proline affect protein binding sites on the csd gene, which in turn lead to different conformational states, which then lead to functional changes in the bees – the switch that determines the shift from female to not female.”
The authors also discovered a natural evolutionary intermediate that showed only three amino acid differences spanned the balance between lethality and induced femaleness, Coulombe wrote. The findings suggest that that incomplete penetrance may be the mechanism by which new molecular switches can gradually and adaptively evolve.
Other co-authors included Christine Seelmann and Tanja Gempe of the University of Duesseldorf; Martin Hasslemann, Institute of Genetics at the University of Cologne, Germany; and Xavier Bekmans with Université Lille, n France. Grants from the Deutsche Forschungsgemeinschaft supported their work.
Page, who studies the evolution of complex social behavior in honey bees, from genes to societies, received his doctorate in entomology from UC Davis in 1980, and served as an assistant professor at Ohio State University before joining the UC Davis Department of Entomology in 1989. He chaired the department for five years, from 1999 to 2004 when ASU recruited him as the founding director and dean of the School of Life Sciences, an academic unit within College of Liberal Arts and Science (CLAS).
Page was selected the university provost in December. He had earlier served as the vice provost.
Recognized as one of the world’s foremost honey bee geneticists, Page is a highly cited entomologist who has authored more than 230 research papers and articles centered on Africanized bees, genetics and evolution of social organization, sex determination and division of labor in insect societies. His work on the self-organizing regulatory networks of honey bees is featured in his new book, The Spirit of the Hive: The Mechanisms of Social Evolution, published in June 2013 by Harvard University Press.
