Chemical ecologist Anjel Helms of Texas A&M University will speak on "The Smells of Dinner, Death, and Danger: How Organisms Navigate Multitrophic Interactions in a Chemical World" at the next virtual seminar hosted by the UC Davis Department of Entomology and Nematology.

The seminar takes place from 4:10 to 5 p.m., Wednesday, Oct. 28. Access this site for the Zoom link. Host is Cooperative Extension specialist and agricultural entomologist Ian Grettenberger, assistant professor, UC Davis Department of Entomology and Nematology. He is coordinating the department's fall seminars.

"The research in our lab focuses on understanding how chemical compounds mediate interactions among microbes, plants, herbivores, and herbivore natural enemies," Helms says. "We combine analytical chemistry and behavioral ecology in laboratory and field-based research to investigate how organisms use chemistry to navigate, communicate, and defend themselves. This seminar will discuss some of our ongoing projects examining how plants and insect herbivores use chemical information from their environment to assess their risk of attack and how herbivore natural enemies use such information to find potential prey." 

Helms, an assistant professor, holds two degrees from Pepperdine University, Malibu, Calif., both awarded in 2009: a bachelor of science degree in biology and a bachelor of arts degree in biochemistry.  She received her doctorate in ecology in 2015 from The Pennsylvania State University, State College, Penn. While in the John Tooker lab, Helms studied the chemical ecology of plant-insect interactions, especially how plants defend themselves against insect herbivores. She  investigated how plants use olfactory cues to predict impeding herbivore attacks and the molecular mechanisms involved.  

In addition to the general field of chemical ecology, Helms' research interests include plant-insect interactions, tritrophic interactions, belowground chemical ecology, chemical communication, and plant defense.

Her most recent publications:

Helms, A.M., Ray, S., Matulis, N.L.*, Kuzemchak, M.C.*, Grisales, W.*, Tooker, J.F., Ali, J.G. Chemical cues linked to risk: Cues from belowground natural enemies enhance plant defences and influence herbivore behaviour and performance. Functional Ecology. 33, 798-808 (2019). DOI: 10.1111/1365-2435.13297

Acevedo, F.E., Smith, P., Peiffer, M., Helms, A.M., Tooker, J.T., Felton, G.W. Phytohormones in fall armyworm saliva modulate defense responses in plants. Journal of Chemical Ecology. (2019). https://doi.org/10.1007/s10886-019-01079-z

Yip, E.C., Sowers, R.P.*, Helms, A.M., Mescher, M.C., De Moraes, C.M., Tooker, J.F. Tradeoffs between defenses against herbivores in goldenrod (Solidago altissima). Arthropod-Plant Interactions. 13, 279-287 (2019). DOI: 10.1007/s11829-019-09674-3

For any technical issues regarding the seminar, contact Grettenberger at imgrettenberger@ucdavis.edu.

Mosquito researcher Maria Onyango, a postdoctoral associate at the New York State Department of Health,  Albany, N.Y., will deliver a virtual seminar hosted by the UC Davis Department of Entomology and Nematology on Wednesday, Oct. 21 on "The Impact of Zika Virus Infection on the Metabolites and Microbiome of Aedes albopictus."

The Zoom seminar, open to all interested persons, will take place from 4:10 to 5 p.m. Click here for the form to obtain the Zoom link to connect.

"In this talk, we are going to demonstrate the tripartite interactions between the microbiome, mosquitoes of the genus Aedes and Zika virus that they transmit," she says. Aedes albopictus is also known as the Asian tiger mosquito.

"My research focuses on the tripartite interactions between the microbiome, mosquitoes as vectors and the arboviruses they transmit," Onyango says. "In addition, I am interested in the role the vector-host- pathogen interface plays in enhancing disease severity in the vertebrate host. The goal of my research is to develop innovative control mechanisms both for the vector and pathogens they transmit."

Host is medical entomologist-geneticist Geoffrey Attardo, assistant professor, UC Davis Department of Entomology and Nematology. Cooperative Extension specialist and assistant professor Ian Grettenberger coordinates the fall seminars.

"Dr. Maria Onyango works on the biology underlying interactions between arboviruses (Zika virus), vector mosquitoes and the associated microbiome," Attardo said.

Along with seven other scientists, Attardo and Onyango co-authored a research article in the Oct. 2nd edition of Frontiers in Microbiology on"Zika Virus Infection Results in Biochemical Changes Associated With RNA Editing, Inflammatory and Antiviral Responses in Aedes albopictus."

The abstract:

"Rapid and significant range expansion of both the Zika virus (ZIKV) and its Aedes vector species has resulted in the declaration of ZIKV as a global health threat. Successful transmission of ZIKV by its vector requires a complex series of interactions between these entities including the establishment, replication and dissemination of the virus within the mosquito. The metabolic conditions within the mosquito tissues play a critical role in mediating the crucial processes of viral infection and replication and represent targets for prevention of virus transmission. In this study, we carried out a comprehensive metabolomic phenotyping of ZIKV infected and uninfected Ae. albopictus by untargeted analysis of primary metabolites, lipids and biogenic amines. We performed a comparative metabolomic study of infection state with the aim of understanding the biochemical changes resulting from the interaction between the ZIKV and its vector. We have demonstrated that ZIKV infection results in changes to the cellular metabolic environment including a significant enrichment of inosine and pseudo-uridine  levels which may be associated with RNA editing activity. In addition, infected mosquitoes demonstrate a hypoglycemic phenotype and show significant increases in the abundance of metabolites such as prostaglandin H2, leukotriene D4 and protoporphyrinogen IX which are associated with antiviral activity. These provide a basis for understanding the biochemical response to ZIKV infection and pathology in the vector. Future mechanistic studies targeting these ZIKV infection responsive metabolites and their associated biosynthetic pathways can provide inroads to identification of mosquito antiviral responses with infection blocking potential."

Onyango holds two degrees from the University of Nairobi, Kenya: a bachelor of science degree in biochemistry and zoology and a master's degree in applied parasitology. She received her doctorate in veterinary entomology from Deakin University and Australian Animal Health Laboratory, Commonwealth Scientific and Industrial Research Organisation (CSIRO), and then completed postdoctoral training at the Yale School of Public Health, Department of Epidemiology of Microbial Diseases. 

For any technical issues regarding the seminar, contact Grettenberger at imgrettenberger@ucdavis.edu

Want to learn more about arthropods in rice and alfalfa fields and the UC Davis research underway to help the agriculturists?

Cooperative Extension agricultural specialist Ian Grettenberger, assistant professor, UC Davis Department of Entomology and Nematology, and his graduate student, Madison "Madi" Hendrick, will discuss the crops, the pests, and the natural enemies or beneficials at a virtual Facebook live session from 11 a.m. to noon, Thursday, Oct 22.

The event, "The Good and the Bad: Insects and Other Arthropods in Agriculture, with a Focus on California Rice and Alfalfa," will be live-streamed on the UC Davis Bohart Museum of Entomology's Facebook page. (Link to Facebook live here). Grettenberger and Hendrick will present short talks and then field questions.  No personal Facebook account is required to join the session, which is free and open to the public.

"This is all about the arthropods, both the pests and beneficials that they study in the rice and alfalfa fields," said Tabatha Yang, education and outreach coordinator for the Bohart Museum of Entomology. "Most of the focus is on insects, but tadpole shrimp in rice fields also will be discussed." A virtual family craft activity is also planned.

"I will be discussing some of the insect (or arthropod) problems faced by growers of rice in California and some of the challenges in managing them, Grettenberger said. "In rice, some of the key arthropod pests are tadpole shrimp, which can turn what would have been a lush stand if rice into a poor stand with a lot of floating seedlings. Meanwhile, later in the year, armyworm caterpillars, the larvae of a moth, can chew on rice leaves and destroy plants. I'll discuss some of the ongoing work to better understand and manage these pests."

Grettenberg's fields of expertise include field and vegetable crops; integrated pest management; applied insect ecology, and biological control of pests. (See Spotlight on Ian Grettenberger.) Among his current grants:

• Protection of rice from invertebrate pests
• Insecticide resistant alfalfa weevils in the western United States: Quantifying the scope of resistance and implementing a plan to manage the threat?
• Management of key cotton arthropod pests with insecticides and acaricides, a proactive approach to prepare for the invasion of the tomato leafminer (Tuta absoluta)  into California
• Detection, biology and control of the exotic Swede midge (Contarinia nasturtii) for California cole crops
• Management of the western spotted and striped cucumber beetle in melon production
• Biological control of the bagrada bug
• Insecticide resistance monitoring and evaluation of efficacy of current chemical tactics for managing aphids and thrips in lettuce

Grettenberger joined the UC Davis Department of Entomology and Nematology in January 2019. Grettenberger, who fills the vacated position of Larry Godfrey (1956-2007), received his bachelor of science degree in biology, with an ecology, evolution and organismal emphasis (honors program) in 2009 from Western Washington University, Bellingham, Wash., and his doctorate in entomology in 2015 from Pennsylvania State University, State College, Pa. He served as a postdoctoral researcher in the Godfrey lab and later, the Frank Zalom lab, before accepting his current appointment of assistant Cooperative Extension specialist.

What sparked his interest in entomology? "I had biologist parents, and was drawn into entomology at a pretty young age," Grettenberger said. "I spent plenty of time looking in flowers and turning over logs looking for insects. Once I started thinking about going to graduate school for entomology, I decided to focus on the intersection of agricultural entomology and insect ecology. I wanted to work on applied issues in entomology."

Hendrick, a second-year graduate student in the Grettenberger lab, received her bachelor's degree in iInternational studies at North Carolina State University, and also spent a semester at Nagoya University in Japan (she minored in Japanese).

"I got my start in entomology completely by chance!," Hendrick related. "I needed a science credit and happened to pick a class called 'Insects and People.”' That class really helped me to reframe the way I thought about insects and appreciate what interesting little critters they are. Through that class, I was also able to get a job as an undergraduate assistant in an entomology lab. I worked in a specialty crops lab, where I developed interests in integrated pest management and invasive species. I now study insecticide resistance in the alfalfa weevil, and I'm excited to share what I've learned through this outreach event!"

Grettenberger, Yolo County Farm Advisor Rachael Freeman Long and Madi Hendrick recently wrote a piece in the UC Agricultural and Natural Resources (UC ANR) blog, Alfalfa and Forage News, "A (Virtual )Update on Worms, Weevils an Aphids in Alfalfa."

"This year, the Kearney Research and Extension Center Alfalfa and Forage Field Day went virtual," Grettenberger wrote. "Attendees did not get the chance to look out over lush fields of alfalfa or towering plantings of sorghum, but they get did an update on ongoing work in alfalfa and other forages. Our team put together a rapid-fire video to discuss what are typically the key insect pests in California alfalfa: summer worms, alfalfa weevils, and aphids."

The summer worms in alfalfa include the summer worms: Western yellowstriped armyworm, beet armyworm and alfalfa caterpillar. Another key pest is the alfalfa weevil. The trio also discussed  aphids and their natural enemies, including lady beetles, aka ladybugs).

Pests of rice include armyworms, aster leafhoppers, crayfish, rice leafminers, rice seed midges, rice water weevils and tadpole shrimp.

The Bohart Museum, directed by Lynn Kimsey, UC Davis professor of entomology, is located in Room 1124 of the Academic Surge Building on Crocker Lane, UC Davis campus, but is temporarily closed. The museum houses nearly eight million insect specimens; a live "petting zoo" of Madagascar hissing cockroaches, walking sticks and taranatulas; and a gift shop stocked with insect-themed T-shirts, books, posters, jewelry, candy and insect-collecting equipment. 

More information on the Bohart Museum's virtual presentation is available on its website or by contacting Yang at tabyang@ucdavis.edu.

Resources: 

• Alfalfa and Forage News: A (Virtual) Update on Worms, Weevils and Aphids in Alfalfa (By Ian Grettenberger, Rachael Freeman Long and Madi Hendrick, Sept. 20, 2020) (See video on same page)
• Alfalfa and Forage News: Natural Enemies Are Important for Control of the Aphid Complex in Alfalfa--A Case Study (By Ian Grettenberger, Rachael Freeman Long, Daniel Putnam and Rob Wilson, April 7, 2020)
• UC Statewide Integrated Pest Management Program: How to Manage Pests of Alfalfa
• UC Statewide Integrated Pest Management Program: Insects and Other Pests of Rice

 

Global change ecologist Amanda Koltz, a senior scientist with the Department of Biology, Washington University, St. Louis, will speak on "Species Interactions and Ecosystems in a Changing World" at the UC Davis Department of Entomology and Nematology's virtual seminar at 4:10 p.m., Wednesday, Oct. 14. 

"Biological communities and species interactions are changing rapidly as a result of global change," she says in her abstract. "These changes are likely to have cascading effects on ecosystems, but we still have limited understanding of the extent to which organismal responses to global change may also drive ecosystem responses to it. In this talk, I will present some of my work on the potential feedbacks between global change, communities, and ecosystem functioning from two different study systems. First, I will discuss how warming can alter the cascading effects of spiders in the Arctic tundra, and then I will discuss my recent efforts at characterizing the potential consequences of shifting interactions among ruminant hosts and their parasites. The common theme throughout the talk will be the importance of considering species interactions in efforts to understand ecosystem responses to global change."

Koltz describes herself as a "global change ecologist interested in how species interactions influence community composition and ecosystem function in the context of environmental change. I use common, widespread organisms that are sensitive to change-- like wolf spiders, mosquitoes and gut worms--to better understand how the animals in our everyday lives impact the ecosystems we live in. My recent work focuses on two fundamental questions: (1) How do biological communities respond to changes in the environment? and (2) What are the consequences of changes in species interactions for the cycling of energy and nutrients within ecosystems?"

Cooperative Extension specialist and agricultural entomologist Ian Grettenberger,  assistant professor, UC Davis Department of Entomology and Nematology, coordinates the fall series of virtual seminars. They are held on Wednesdays at 4:10 p.m.

Host for the Koltz seminar is Emily Meineke, assistant professor of urban landscape entomology, who researches insect-plant interactions.

Grettenberger announced that this is the form to obtain the zoom link:

https://docs.google.com/forms/d/1JHRitzyKtU2MzBTywYq6AyzuX6sIjVL-NDk_s8Ilnp4/edit

Koltz's research has appeared in a number of recent publications: 

• Small but Mighty: Measuring Parasites' Footprints
• Wolf Spiders May Turn to Cannibalism in a Warming Arctic
• Warming Alters Predator-Prey Interactions in the Arctic
• Bugged Out by Climate Change
• Higher Education Channel: Arctic Wolf Spider's Changing Diet May Help Keep Arctic Cool & Lessen Some Impact of Global Warming