- Author: Kathy Keatley Garvey
Her seminar takes place at 3:30 in 366 Briggs Hall, and also will be on Zoom.
Mack studies Aedes aegypti with a focus on analysis of transcriptomic datasets and 3D imaging datasets. "Throughout my time in graduate school, my projects have considered pyrethroid resistance in Aedes aegypti ;examining the genetic response to this insecticide. As I finish up my dissertation, I hope to pursue a career in industry using the skills I've developed to continue to analyze large datasets!"
Insecticide resistance is a global issue, Mack says in her exit seminar abstract. Ae. aegypti, known as "the yellow fever mosquito," can transmit dengue fever, chikungunya, Zika fever, Mayaro and yellow fever viruses, and other disease agents. The mosquito was first colonized California in 2013 and arrived resistant to pyrethroids. "The pyrethroid target site genotype differs geographically in California and partially infers resistance phenotype, indicating that other mechanisms are at play as well."
"Since their detection in 2013, Aedes aegypti has become a widespread urban pest in California," the co-authors wrote in the abstract. "The availability of cryptic larval breeding sites in residential areas and resistance to insecticides pose significant challenges to control efforts. Resistance to pyrethroids is largely attributed to mutations in the voltage gated sodium channels (VGSC), the pyrethroid site of action. However, past studies have indicated that VGSC mutations may not be entirely predictive of the observed resistance phenotype."
"To investigate the frequencies of VGSC mutations and the relationship with pyrethroid insecticide resistance in California, we sampled Ae. aegypti from four locations in the Central Valley, and the Greater Los Angeles area. Mosquitoes from each location were subjected to an individual pyrethrum bottle bioassay to determine knockdown times. A subset of assayed mosquitoes from each location was then analyzed to determine the composition of 5 single nucleotide polymorphism (SNP) loci within the VGSC gene."
The conclusion:
"Resistance associated VGSC SNPs are prevalent, particularly in the Central Valley. Interestingly, among mosquitoes carrying all 4 resistance associated SNPs, we observe significant heterogeneity in bottle bioassay profiles suggesting that other mechanisms are important to the individual resistance of Ae. aegypti in California."
Mack, who holds a bachelor of science degree (2018) in biology from Creighton University, Omaha, Neb., enrolled in the UC Davis graduate school program in 2018.
Active in the Entomological Society of America, Mack scored second place in student competition at the 2022 joint meeting of the Entomological Societies of America, Canada, and British Columbia, held last November in Vancouver, British Columbia. She entered her presentation, "Three Dimensional Analysis of Vitellogenesis in Aedes aegypi Using Synchrotron X-Ray MicroCT,” in the category, "Graduate School Physiology, Biochemistry and Toxicology: Physiology.
Her abstract: "Traditional methods of viewing the internal anatomy of insects require some degree of tissue manipulation and/or destruction. Using synchrotron-based x-ray phase contrast microCT (pcMicroCT) avoids this issue and has the capability to produce high contrast, three dimensional images. Our lab is using this technique to study the morphological changes occurring in the mosquito Aedes aegypti during its reproductive cycle. Ae. aegypti is the primary global arbovirus vector, present on all continents except Antarctica. Their ability to spread these viruses is tightly linked with their ability to reproduce, as the production of eggs in this species is initiated by blood feeding. Amazingly, this species produces a full cohort of eggs (typically 50-100) in just 3 days' time following a blood meal. This rapid development represents dramatic shifts in physiological processes that result in massive volumetric changes to internal anatomy over time. To explore these changes thoroughly, a time course of microCT scans were completed over the vitellogenic period. This dataset provides a virtual representation of the volumetric, conformational, and positional changes occurring in tissues important for reproduction across the vitellogenic period. This dataset provides the field of vector biology with a detailed three-dimensional internal atlas of the processes of vitellogenesis in Ae. aegypti."
"As for career plans, I am applying to computational biology positions in industry," Mack said. "I'm not filing my dissertation until July so I am still working on this."

- Author: Kathy Keatley Garvey
She will speak at 4:10 p.m. in 122 Briggs Hall. Her seminar also will be virtual. The Zoom link: https://ucdavis.zoom.us/j/95882849672.
"Parasites often manipulate their hosts' behavior and physiology, resulting in detrimental effects on host fitness," Worthington says in her abstract. "The horsehair worm (Paragordius varius) is a long-lived parasite that infects arthropods, including the sand field cricket, Gryllus firmus. This parasite lives inside its host for upwards of 28 days and can grow as long as 30 cm, presenting a significant challenge for its host's own growth, survival, and reproduction."
"Here, we tested the ability of infected male crickets to invest in immunity, somatic growth, and reproductive structures," she noted. "We also compared courtship behaviors, calling abilities, and mating success rates between infected and healthy males to identify how host reproductive fitness is affected by this large, long-lived parasite. Our results demonstrate surprisingly few physiological trade-offs, yet preliminary research suggests a reproductive burden on infected males, where even when host male crickets are able to survive horsehair worm infection, they will likely suffer from significantly reduced lifetime reproductive fitness."
Seminar host is doctoral candidate Lindsey Mack of the laboratory of medical entomologist-geneticist Geoffrey Attardo. "Dr. Worthington was my undergraduate research advisor," said Mack, adding. "She studies reproduction/immune trade-offs in crickets. Currently, her work focuses on the reproductive costs of high parasitic loads in field crickets, but she has experience with stalk=eyed flies, rhinoceros beetles, horsehair worms, and many other organisms. Generally, she is interested in wild sexually selected morphologies and behaviors."
"Additionally, she teaches at a religiously affiliated, primarily undergraduate institution (Creighton is a private Jesuit research university) and would be a great person to talk to about this type of career," Mack said. A pre-seminar coffee takes place from 3:30 to 4:10 p.m. in 158 Briggs.
Worthington, who joined Creighton's Department of Biology in the fall of 2016, holds a bachelor's degree in biology from the University of South Dakota (USD), and also received her master's degree at USD, studying the anti-predator behaviors of stalk-eyed flies and managing a long-term project dedicated to conserving the federally endangered Hine's Emerald dragonfly.
Worthington completed her doctorate in ecology and evolutionary biology at Iowa State University, researching mating behavior in field crickets. She then transitioned into a postdoctoral fellowship at Washington State University where she worked on the development of sexually selected weapons in rhinoceros beetles and the hormonal mechanisms mediating wing polymorphism in crickets.
"Broadly, I am fascinated by bizarre morphologies and behaviors that are the result of sexual selection," Worthington says on her website. "Specifically, I am interested in the functional and physiological costs of these traits. I focus on trade-offs between reproduction and immunity, but also investigate topics such as sperm competition, the benefits of polyandry, and the molecular/hormonal mechanisms responsible for life-history tradeoffs. I have worked with a diverse array of invertebrate taxa (stalk-eyed flies, jumping spiders, dragonflies, crayfish, snails, and rhinoceros beetles), but currently focus my research on Gryllus firmus crickets. One particular interest is how individuals respond to long-term parasitic infections by the horsehair worm Paragordius varius, and how this infection impacts life-long fitness in its host."
The UC Davis Department of Entomology and Nematology's winter seminars are held on Wednesdays at 4:10 p.m. in 122 Briggs Hall. All are virtual. Urban landscape entomologist Emily Meineke, assistant professor, coordinates the seminars. (See schedule.) She may be reached at ekmeineke@ucdavis.edu for technical issues.

- Author: Kathy Keatley Garvey
This was Rutkowski's second consecutive President's Prize.
Doctoral candidate Lindsey Mack and doctoral student Adelaine “Addie” Abrams scored second-place for their research presentations in the highly competitive program.
Their topics ranged from bumble bees (Rutkowski) and ants (Griebenow) to mosquitoes (Mack) and thrips and aphids (Abrams).
At the Entomological Society of America (ESA) annual meetings, students are offered the opportunity to present their research and win prizes. They can compete in 10-minute papers (oral), posters, or infographics. The President's Prize winners receive a one-year paid membership in ESA, a $75 cash prize, and a certificate. Second-winners score a one-year free membership in ESA and a certificate.
Danielle Rutkowski
Danielle Rutkowski, who studies with community ecologists Rachel Vannette, associate professor, and distinguished professor Richard “Rick” Karban, spoke on “The Mechanism Behind Beneficial Effects of Bee-Associated Fungi on Bumble Bee Health,” at her presentation in the category, Graduate School Plant-Insect Ecosytems: Pollinators.
Her abstract: "Bees often interact with fungi, including at flowers and within bee nests. We have previously found that supplementing bumble bee colonies with these bee-associated fungi improves bee survival and increases reproductive output, but the mechanisms behind these effects are unclear. This research aimed to determine the mechanisms underlying positive impacts of fungal supplementation in the bumble bee, Bombus impatiens. We tested two hypotheses regarding possible nutritional benefits provided by bee-associated fungi. These included the role of fungi as a direct food source to bees, and the production of nutritionally important metabolites by fungi. To test these mechanisms, we created microcolonies bumble bees and exposed each microcolony to one of four treatment groups. These four treatments were created based on the presence of fungal cells and the presence of fungal metabolites. We found that bee survival and reproduction were unaffected by treatment, with trends of decreased survival and reproduction when fungi were present. This contradicts previous results we've found using this bumble bee species, where fungi had a positive impact. It is possible that this disparity in results is due to differences in pathogen pressure between the two experiments, as bees in the first experiment were exposed to large amounts of pathogen through provided pollen, including Ascosphaera and Aspergillus. This pollen was sterilized for subsequent experiments, reducing pathogen load. Therefore, it is possible that bee-associated fungi benefit bees through pathogen inhibition, and future work exploring this hypothesis is necessary to fully understand the role of these fungi in bumble bee health."
Zach Griebenow, who studies with major professor and ant specialist Phil Ward, (Griebenow also captained the UC Davis Entomology Games Team in its national championship win at the Entomology Games or Bug Bowl) explained “Systematic Revision of the Obscure Ant Subfamily Leptanillinae (Hymenoptera: Formicidae), Reciprocally Informed by Phylogenomic Inference and Morphological Data.” His category: Graduate School Systematics, Evolution and Biodiversity: Evolution 1.
His abstract: "Ants belonging to the subfamily Leptanillinae (Hymenoptera: Formicidae) are sister to nearly all other extant ants. Miniscule and subterranean, little is known of their behavior. Contrary to the collecting bias observed in most ants, male leptanilline specimens are acquired more easily than workers or queens. The sexes are almost never collected in association, and many subclades within the Leptanillinae are known from male specimens only. Our comprehension of evolutionary relationships among the Leptanillinae is further obstructed by oft-bizarre derivation in male phenotypes that are too disparate for phylogeny to be intuited from morphology alone. These restrictions plague our understanding of the Leptanillinae with probable taxonomic redundancy. My thesis aims at leptanilline taxonomy that reflects phylogeny, inferred from both genotype and phenotype, and integrates morphological data from both sexes. Here I present the results of (1) phylogenomic inference from ultra-conserved elements (UCEs), compensating for potential systematic biases in these data, representing 63 terminals; and (2) Bayesian total-evidence inferences from a handful of loci, jointly with discrete male morphological characters coded in binary non-additive or multistate fashion. Notably, these analyses identify worker specimens belonging to the genera Noonilla and Yavnella, which were heretofore known only from males. Given such discoveries across the Leptanillinae, the number of valid leptanilline genera is reduced from seven to three in order to create a genus-level classification that upholds monophyly along with diagnostic utility."
Mack, who studies with medical entomologist-geneticist Geoffrey Attardo, assistant professor, covered “Three Dimensional Analysis of Vitellogenesis in Aedes aegypi Using Synchrotron X-Ray MicroCT” in the category, Graduate School Physiology, Biochemistry and Toxicology: Physiology.
Her abstract: "Traditional methods of viewing the internal anatomy of insects require some degree of tissue manipulation and/or destruction. Using synchrotron-based x-ray phase contrast microCT (pcMicroCT) avoids this issue and has the capability to produce high contrast, three dimensional images. Our lab is using this technique to study the morphological changes occurring in the mosquito Aedes aegypti during its reproductive cycle. Ae. aegypti is the primary global arbovirus vector, present on all continents except Antarctica. Their ability to spread these viruses is tightly linked with their ability to reproduce, as the production of eggs in this species is initiated by blood feeding. Amazingly, this species produces a full cohort of eggs (typically 50-100) in just 3 days' time following a blood meal. This rapid development represents dramatic shifts in physiological processes that result in massive volumetric changes to internal anatomy over time. To explore these changes thoroughly, a time course of microCT scans were completed over the vitellogenic period. This dataset provides a virtual representation of the volumetric, conformational, and positional changes occurring in tissues important for reproduction across the vitellogenic period. This dataset provides the field of vector biology with a detailed three-dimensional internal atlas of the processes of vitellogenesis in Ae. aegypti."
Abrams, who studies with Extension agricultural entomologist and assistant professor Ian Grettenberger (she is a member of the Horticulture and Agronomy Graduate Group), titled her research, “Hitting the Mark: Precision Pesticide Applications for the Control of Aphids in California Lettuce" in the category, Graduate School Physiology, Biochemistry and Toxicology: Integrated Pest Management.
Her abstract: "Commercial lettuce production in California's central coast represents 70 percent of the production in the United States. Recent discoveries of some chemistries in ground and surface water in the Salinas valley region have placed the insecticidal chemistries used by the industry at risk of increased regulation. Automated thinner-sprayers use plant-detection sensors to apply chemical sprays directly to individual lettuce plants, so that the same amount of product to plants as a standard broadcast sprayer while potentially reducing the amount of pesticide applied per acre by up to 90 percent. Field experiments testing this technology for the control of western flower thrips (Frankliniella occidentalis) and aphids, lettuce-currant aphid (Nasovonia ribisnigri) and others, were conducted to compare the efficacy of automated sprays to a conventional broadcast application system. Experiments were conducted in conventionally managed organic romaine lettuce fields using a complete randomized block design. Prior to and at regular intervals after treatment, heads were sampled from experimental and control plots to assess pest pressure. Results from this experiment validate the use of the automated sprayers to apply insecticides for the control of aphid and thrips pests in lettuce and will be discussed in the context of developing best-use-practices for this technology."
The 7000-member ESA, founded in 1889, is the largest organization in the world serving the professional and scientific needs of entomologists and individuals in related disciplines. Its members, affiliated with educational institutions, health agencies, private industry, and government, are researchers, teachers, extension service personnel, administrators, marketing representatives, research technicians, consultants, students, pest management professionals, and hobbyists.
(See all of student competition winners on ESA site)
- Author: Kathy Keatley Garvey
A total of 10 entomology graduate students will deliver presentations in the 10-minute oral student competitions, and two will present posters. The events are scheduled Monday, Nov. 1.
10-Minute Student Speech Competitions:
- Jill Oberski, doctoral candidate who studies with major professor Phil Ward
Category: Systematics, Evolution and Biodiversity: Phylogenetics and Phylogenomics
Title: "Arid-Adapted Pyramid Aants (Formicidae: Dorymyrmex) Show an Amphitropical Distribution and an Ongoing Radiation." - Zachary Griebenow, doctoral candidate who studies with major professor Phil Ward
Category: Systematics, Evolution and Biodiversity: Parasites and Symbionts
Title: "Discovery of a Putative Troglomorphic Ant (Hymenoptera: Formicidae: Leptanillinae)"
- Lacie Newton, doctoral candidate who studies with major professor Jason Bond
Category: Systematics, Evolution and Biodiversity: Phylogentics and Phylogenomics
Title: "Establishing a Robust Combined-Evidence Phylogeny of the Trapdoor Spider Genus Aptostichus (Araneae: Mygalomorphae: Euctenizidae)" - Lindsey Mack, PhD student who studies with major professor Geoffrey Attardo
Category: Medical, Urban and Veterinary Entomology: Mosquitoes, Biting Midges and Flies
Title: "Gene Expression Temporal Analysis of Pyrethroid Response in Californian Aedes aegypti" - Danielle Rutkowski, PhD student who studies with major professor Rachel Vannette
Category: Plant-Insect Ecosystems: Ecology 3
Title: "Fungicide Impacts on Bumble Bees are Mediated via Effects on Bee-Associated Fungi" - Maureen Page, doctoral candidate who studies with major professor Neal Williams
Category: Plant-Insect Ecosystems: Pollinators
Title: "Optimizing Pollinator-friendly Plant Mixes to Simultaneously Support Wild and Managed Bees" - Xavier Zahnle, PhD student who studies with major professor Jason Bond
Category: Systematics, Evolution and Biodiversity: Evolution
Title: "Deep Homology Influences Llocalized Postembryonic Metamorphosis in Male Genitalia of the Flat-Backed Millipede Pseudopolydesmus serratus (Myriapoda, Diplopoda,Polydesmida,Polydesmidae)" - Erin T. Kelly, doctoral candidate who studies with major professor Geoffrey Attardo
Category: Physiology, Biochemistry and Toxicology: Molecular Biology, Cellular Biology and Biochemistry
Title: "Using Metabolomic Analysis to Generate Insights into Pyrethroid Metabolism and Resistance in California Aedes aegypti" - Jasmin Ramirez Bonilla, master's student who studies with major professor Ian Grettenberger
Category: Plant and Insect Ecosystems: Field Crops 3
Title: "Stripes and spots: Evaluating an Aggregation Pheromone, vittatalactone, for Western Striped (Acalymma trivittatum) and Western Spotted (Diabrotica undecimpunctata undecimpunctata) Cucumber Beetles" - Madison Hendrick, PhD student who studies with major professor Ian Gettenberger
Category: Plant and Insect Ecosystems: Field Crops 1
Title: "Clarifying Pyrethroid Resistance and Exploring Interactions with Insecticide Use in California Alfalfa Weevil"
Posters:
- Mia Lippey, PhD student who studies with major professors Jay Rosenheim and Emily Meineke
Poster in the Plant-Insect Ecosystems Section, Behavior and Ecology: "Effects of Surrounding Landscapes on the Fork-tailed Bush Katydid (Scudderia furcata) in California Citrus" - Gabriel "Gabe" Foote, PhD student who initially studied with (the late) Steve Seybold and is now advised by Hugh Safford Region 5 Regional Ecologist/Affiliate Faculty (UC Davis).
Poster in Plant-Insect Ecosystems Section, Pollinators, "Landscape and Stand Level Factors Affecting Wild Bee Diversity in the Californian Central Sierra Nevada"
Abstracts:
Speech Competition
Jill Oberski
Zachary Griebenow
Xavier J. Zahnle
In the arthropod subphylum Myriapoda, localized modification of walking legs is taxonomically widespread. Male millipedes (class Diplopoda) exemplify this phenomenon, with diverse postembryonic walking leg transformations including clasping organs, reduced or hyper-enlarged leg pairs, and intromittent copulatory genitalia called gonopods. Gonopods are fully formed in adult males, but usually develop internally through several stadia.
Special attention was paid to the origin and insertion points of muscles as potential points of topological continuity preserved through development. Additionally, a series of juvenile male Pseudopolydesmus stadia was imaged using µCT to investigate the structural transformation of the future gonopod appendage pair. Topological continuity of muscles between walking legs and gonopods could be established for only a few muscles. Moreover, the developmental series revealed near-complete obliteration of appendicular muscles before adult gonopod formation begins, disproving the hypothesis that gonopod muscles are physically retained serialhomologs of those in the walking legs. Therefore, the few structural similarities between muscles in walking legs and gonopods are more likely due to the structure being preserved from the ancestral node of gonopod-bearing millipedes (deep homology) than to developmental continuity within the individual. (Co-authors of paper are Professor Jason Bond and Megan Ma.)

Lindsey Mack

Danielle Rutkowski
Maureen Page
Despite the recognized utility of wildflower plantings to support honey bees and wild bees these two goals have largely been pursued separately. Furthermore, pollinator-friendly plant mixes are currently selected using estimates of flower visitation without considering among-plant differences in nutritional quality or how competition among bees might affect plant use. The nutritional composition of pollen and nectar strongly affects bee health and survival and bees use nutritional information to make plant foraging decisions. Additionally, honey bees, which are generally stocked at high densities in crop lands, have been shown to compete with native pollinators for pollen and nectar resources and such competition may lead to changes in plant choice and narrowing of diet breadth. In this study, I use data on flower visitation patterns and the nutritional quality of nectar and pollen from different plant species in conjunction with recently developed optimization models to identify plant mixes that meet the goals of enhancing honey bee nutrition and maximizing support of diverse bee communities while minimizing competition. (Paper co-authored by Professor Neal Williams)


Madison Hendrick
Posters
Mia Uppey

Gabriel Foote
Kyle Lewald, College of Biological Sciences and Member of the Joanna Chiu Lab
Tuta absoluta represents one of the largest threats to tomato production worldwide. While initially contained to South America throughout the 20th century, T. absoluta were detected in Spain in 2006 before rapidly spreading throughout Europe and Asia over the next decade. To facilitate study of pesticide resistance, adaptation, and control strategies, researchers require a high quality, highly contiguous, and well-annotated genome assembly. The currently published genome assembly was generated using short-read technology for the purpose of developing molecular markers and studying population genetics; however, due to the genome's large size, heterozygosity, and repetitiveness, the assembly was highly fragmented, making it unsuitable for annotation or functional genomic studies. To address this, we extracted DNA from a single T. absoluta individual for sequencing with long-read PacBio HiFi technology to avoid assembly issues expected due to high genetic diversity and repetitiveness. We have now successfully created a diploid assembly that contains 98% of complete BUSCO groups and 99% of initial raw reads, with an N50 of 6Mb. The genome is 3% heterozygous, and is 60% composed of repeat elements, explaining the fragmented nature of the previous assemblies. By annotating this assembly with previously published RNAseq, protein, and repeat-element datasets, we expect this resource to advance efforts in understanding and developing control strategies for this invasive moth. (Co-author is Joanna Chiu)
The 7000-member Entomological Society of America, founded in 1889 and headquartered in Annapolis, Md.,, is the world's largest organization serving the professional and scientific needs of entomologists and others in
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