- Author: Kathy Keatley Garvey
But that's the case with UC Davis doctoral student Grace Horne. Her undergraduate thesis about the effects of the decline of ash trees on native caterpillars, scored the cover of the February edition of the journal Environmental Entomology. Or, should we say, it "graced" the cover.
The paper, “Specialist Herbivore Performance on Introduced Plants During Native Host Decline,” is co-authored by Ria Manderino of the Oak Spring Garden Foundation, Upperville, VA and Samuel Jaffe of The Caterpillar Lab, Marlborough, N.H.
“Our publication highlights the importance of multispecies assessments of host plant acceptance,” said Horne, who studies plant-insect interactions, urban ecology, global change biology, natural history and community science in the laboratory of urban landscape entomologist Emily Meineke, assistant professor, UC Davis Department of Entomology and Nematology.
“We tested three related species, two of them congeners, on their ability to accept alternative host plants in the face of the loss of their primary host," Horne said. "We found a diversity of responses even among these three species. Further downstream, landscape managers may be able to use our results to make decisions about which plantings will help support native herbivores.”
Jaffe provided the cover image of a Sphinx kalmiae, commonly known as "laurel sphinx."
The abstract:
Ash (Fraxinus spp.) is in rapid decline across the northeastern USA due to the invasive emerald ash borer (Agrilus planipennis Fairmaire). Three recently co-occurring confamilial species may serve as alternative larval host plants for ash-reliant Lepidoptera. These prospective hosts are nonnative shrubs often planted in managed suburban landscapes and are sometimes invasive or naturalized in North America. Given the imminent decline of ash trees, we considered potential downstream effects on insect herbivores historically specialized on ash foliage. We measured the performance of three ash-specialist hawkmoths (Lepidoptera: Sphingidae) on native white ash (Fraxinus americana L.) and alternative host plants: common lilac (Syringa vulgaris L.), weeping forsythia [Forsythia suspensa (Thunb.) Vahl], and European privet (Ligustrum vulgare L.). We found the nonnative host plants provided varied support for larval survival to pupation, with biomass and growth rate affected differently by both plant and insect identity. Nearly all caterpillars reared on one alternative host, European privet, exhibited distinct malformations of the wing buds at pupation. Given caterpillar presence on privet in the field, privet may constitute an ecological trap (i.e., when female moths select a sub-optimal host, offspring survival and fitness are reduced). This work demonstrates how performance testing can reveal species-specific effects of host plant loss on mono- or oligophagous insects. For some ash specialists, alternative nonnative host plants may be suboptimal, but some cultivated host plants may be able to support certain specialist insects during native host decline. We suggest that landscaping decisions can be tailored to support threatened insect species."
Graduate of Colby College. Grace is a 2021 graduate of Colby College, Waterville, Maine, where she majored in biology (evolution and ecology), and environmental science (conservation biology), receiving magna cum laude (with distinction) in both majors. Her thesis: “Reduced Performance of Ash-Specialist Caterpillars on Nonnative, Cultivated Oleaceous Plants.”
Horne joined the Meineke lab in 2021 after serving as an education staff member and undergraduate researcher at The Caterpillar Lab, Marlborough, N.H. from 2018-2021. The environmental education organization focuses on inviting people—youth and adults alike—to share in stories of ecology, evolution, and natural history. Horne presented at more than 30 venues, including elementary school classrooms, botanical gardens, and children's museums, "with a goal to ignite in us a curiosity of the world we live in, from the smallest leaf-miners to the tallest trees."
Horne gained experience in conservation and education in the spring of 2020 when she participated in the Round River Conservation Studies in Maun, Botswana. The environmental organization operates at the nexus of conservation and education to explore the complex relationship between conservation, people, and wildlife, mostly in Mababe, Botswana. "We worked with local experts to design and maintain wildlife monitoring systems to be used to substantiate economic and environmental decisions," she related.
Check out the recent feature, For Ash-Dependent Insects, Some Plants Make Good Alternatives—But Others Don't, in the Entomological Society of America's Entomology Today publication.
Picnic Day Co-Chair. You'll be able to see more of Horne's leadership at the 109th annual UC Davis Picnic Day on April 15. Horne, active in the UC Davis Entomology Graduate Students' Association (EGSA), is co-chairing the entomological activities with forensic entomologist Robert Kimsey of the Department of Entomology and Nematology faculty.
The entomological events, held at Briggs Hall and the Bohart Museum of Entomology, are both educational and entertaining. At Briggs Hall, look for forest, medical and agricultural entomology displays, and participate in cockroach races, maggot art, and scores of other activities. And over at the Bohart Museum of Entomology, check out the insect specimens and hold such critters as Madagascar hissing cockroaches and stick insects in the live "petting zoo."
Last year Horne displayed pipevine swallowtails, Battus philenor, munching on their host plant, Dutchman's pipe, Aristolochia macrophylla.
"Picnic Day," as the officials say on their website, "is one of UC Davis' most revered traditions and serves as the university's annual Open House for prospective and current students, families, alumni, staff, faculty, and the greater Davis and regional communities."
- Author: Kathy Keatley Garvey
When you're in your garden, look up.
Sometimes you'll see a Gulf Fritillary caterpillar outlined against the sky, munching away on its host plant, the passionflower vine (Passiflora).
The bright orange caterpillars can be as striking as the adults (Agraulis vanillae).
This caterpillar, however, is not the only critter hungry in the Passiflora. We saw evidence that a praying mantis also calls this home. One wing of a Gulf Frit here. One wing of a Gulf Frit there.
Everything eats in the garden.
In a previous Bug Squad, we mentioned that the Gulf Frits are found in many parts of the world and arrived in California (San Diego) in the 1870s, according to butterfly guru Art Shapiro, UC Davis distinguished professor of evolution and ecology. They spread through Southern California in urban settings and were first recorded in the Bay Area about 1908, Shapiro says. They "became a persistent breeding resident in the East and South Bay in the 1950s and has been there since.”
Shapiro says the Gulf Frits “apparently bred in the Sacramento area and possibly in Davis in the 1960s, becoming extinct in the early 1970s, then recolonizing again throughout the area since 2000.”
Yes, they're back and a joy to see.
- Author: Kathy Keatley Garvey
If you have a passionflower vine (Passiflora), you probably have cats.
No, not the four-legged ones that meow, chase mice or cavort with catnip.
These 'cats or caterpillars are part of the life cycle of the Gulf Fritillary butterflies (Agraulis vanillae) and Passiflora is their host plant.
Watch for the chewed leaves, the frass (poo) and the chrysalids.
Expect a cat-tastrophe when predators like the California scrub jays, European paper wasps, and praying mantids appear and the 'cats disappear.
The circle of life...
- Author: Kathy Keatley Garvey
It's Veterans' Day, and after paying tribute to the military veterans (my ancestors have fought in all of our nation's wars, dating back to the American Revolution--and my other half is a U.S. Air Force veteran), I slip out the back door to our pollinator garden to see where the insect action is.
Honey bees and a sole carpenter bee are buzzing on the African blue basil; Gulf Fritillaries are nectaring on the Mexican sunflower (Tithonia); and a cabbage white butterfly is sipping nectar from the Lantana.
But the passionflower vine (Passiflora) steals the show. A Gulf Fritillary has just eclosed from a chrysalis that resembles a thick wad of gum chewed up and spit out and left to mummify; several male Gulf Frits are fluttering around in search of females; and the offspring of previous reunions are crawling on the stems and munching what's left of the leaves.
Overhead, the California scrub jays glance down, as if trying to decide on their luncheon menu: a fat juicy caterpillar or the bird seed scattered in the feeder.
Their choice is clear. They forsake the fat juicy caterpillars for the bird seed. Tomorrow morning, however, there will be several caterpillars missing in action.
- Author: Kathy Keatley Garvey
A member of the UC Davis faculty since 1980, Hammock received his doctorate in entomology and toxicology from UC Berkeley, where he studied insect science. He now devotes his research to human health.
What many people do not know, however, is that he began his career studying how caterpillars turn into butterflies.
That morphed into human health research.
“The work led to the discovery that many regulatory molecules are controlled as much by degradation and biosynthesis,” Hammock related. “The epoxy fatty acids control blood pressure, fibrosis, immunity, tissue growth, pain and inflammation to name a few processes.”
Fast forward to today.
An enzyme inhibitor developed in the Hammock lab and tested in mice by a team of international researchers shows promise that it could lead to a drug to prevent or reduce the disabilities associated with the neurodevelopmental disorders of autism and schizophrenia.
What the Inhibitor Did
"We discovered that soluble epoxide hydrolase (sEH) plays a key role in inflammation associated with neurodevelopmental disorders. Inhibiting that enzyme stops the inflammation and the development of autism-like and schizophrenia-like symptoms in animal models,” said collaborator Kenji Hashimoto, a professor with the Chiba University Center for Forensic Mental Health, Japan. The scientists found higher levels of sEH in a key region of the brain—the prefrontal cortex of juvenile offspring-- after maternal immune activation (MIA).
The news embargo lifted today (March 18) on their research, to appear in the Proceedings of the National Academy of Sciences (PNAS). (Link will be here: https://www.pnas.org/cgi/doi/10.1073/pnas.1819234116.) It's the work of 14 researchers from Chiba University Center for Forensic Mental Health; the Laboratory for Molecular Psychiatry, RIKEN Center for Brain Science, in Wako, Saitama, Japan; and the Hammock laboratory.
Reversed Cognitive and Sciatl Interaction Deficiencies
By inhibiting sEH, the researchers reversed cognitive and social interaction deficiencies in the mice pups. They hypothesize that this is due to increasing natural chemicals, which prevent brain inflammation. In people, this could reduce the disabilities associated with autism, such as anxiety, gastrointestinal disturbances and epilepsy.
Earlier studies have indicated a genetic disposition to the disorders. The team also studied postmortem brain samples from autism patients that confirmed the alterations.
“In the case of both autism and schizophrenia, the epidemiology suggests that both genetics and environment are contributing factors,” said neuroscientist and associate professor Amy Ramsey of the Department of Pharmacology and Toxicology, University of Toronto, who was not involved in the study. “In both cases, maternal infection is a risk factor that might tip the scales for a fetus with a genetic vulnerability. This study is important because it shows that their drug can effectively prevent some of the negative outcomes that occur with prenatal infections. While there are many studies that must be done to ensure its safe use in pregnant women, it could mitigate the neurological impacts of infection during pregnancy.”
Neuroscientist Lawrence David, professor and chair of the School of Public Health, University of Albany, N.Y., who was not involved in the research, said that the study might lead to “an important therapeutic intervention for neurodevelopment disorders.”
“There is increasing evidence that maternal immune activation activities (MIA) during fetal development can lead to aberrant neurobehaviors, including autistic-like activities,” said Lawrence, who studies neuroimmunology and immunotoxicology. The study “suggests that enzymatic control of fatty acid metabolism is implicated in neuroinflammation associated with schizophrenia and autism spectrum disorders. The expression of Ephx2 giving rise to soluble epoxide hydrolase (sEH) influences production of fatty acid metabolites, which elevate inflammation in the experimental model of mice after MIA; the sEH inhibitor TPPU (N-[1-(1-oxopropyl)-4-piperidinyl]-N'-[4-(trifluoromethoxy)phenyl)-urea) was postnatally used to improved behaviors. Analysis of cadaver brains from individuals with ASD also expressed increased sEH. Fatty acid metabolites have been known to affect fetal development, especially that of the brain; therefore, TPPU might be an important therapeutic intervention for neurodevelopmental disorders.”
Molecular bioscientist Isaac Pessah of the UC Davis School of Veterinary Medicine, distinguished professor and associate dean of research and graduate education in the Department of Molecular Biosciences, described the findings as “significant” and called for more detailed and expanded studies.
Autism: 1 of 68 Children
The Center for Disease Control and Prevention (CDC) estimates that 1 in 68 children in the United States have autism, commonly diagnosed around age 3. It is four times more common in boys than girls. CDC defines autism spectrum disorder as a “developmental disability that can cause significant social, communication and behavioral challenges.” The disorder impairs the ability to communicate and interact.
Schizophrenia: 1.2 Percent of Population
Approximately 3.5 million people or 1.2 percent of the population in the United States are diagnosed with schizophrenia, one of the leading causes of disability, according to the Schizophrenia and Related Disorders Alliance of America (SARDAA). Scores more go unreported. Approximately three-quarters of persons with schizophrenia develop the illness between 16 and 25 years of age. Statistics also show that between one-third and one half of all homeless adults have schizophrenia, and 50 percent of people diagnosed have received no treatment. Among the symptoms: delusions, hallucinations, disorganized speech, disorganized or catatonic behavior, and obsessive-compulsive disorders, such as hoarding, according to SARDAA.
In their research paper, titled “Key Role of Soluble Epoxide Hydrolase in the Neurodevelopmental Disorders of Offspring After Maternal Immune Activation,” the scientists described sEH as “a promising prophylactic or therapeutic target for neurodevelopmental disorders in offspring after MIA.”
First author Min Ma and second Qian Ren of the Hashimoto lab conducted the animal and biochemical work, while chemists Jun Yang and Sung Hee Hwang of the Hammock lab performed the chemistry and analytical chemistry. Takeo Yoshikawa, a team leader with the RIKEN's Molecular Psychiatry Laboratory, performed measurements of gene expression in the neurospheres from iPSC (induced pluripotent stem cells) from schizophrenia patients and postmortem brain samples from autism patients.
Exciting and Productive
Hashimoto described the international collaboration as “exciting and productive.” This is their third PNAS paper in a series leading to endoplasmic reticulum stress. “We report discovery of a biochemical axis that leads to multiple neurological disorders, including depression, Parkinson's disease, schizophrenia, autism spectrum disorders and similar diseases,” he said.
William Schmidt, vice president of clinical development at EicOsis, a Davis-based company developing inhibitors to sEH to treat unmet medical needs in humans and companion animals, said the company is developing a first-in-class therapy for neuropathic and inflammatory pain. “EicOsis is in the process of finalizing our first human trials on the inhibitors of the soluble epoxide hydrolase, originally reported from UC Davis,” Schmidt said. “We are targeting the compounds as opioid replacements to treat peripheral neuropathic pain. It is exciting that the same compound series may be used to prevent or treat diseases of the central nervous system.”
Several grants from the National Institutes of Health, awarded to Hammock, supported the research. Hammock praised the many collaborators and students he has worked with on the project. “This work illustrates the value of research universities in bringing together the diverse talent needed to address complex problems,” Hammock said. “It also illustrates the value of fundamental science. This autism research can be traced directly to the fundamental question of how caterpillars turn into butterflies.”