The research paper, “Introduced Herbivores Restore Late Pleistocene Ecological Functions” is the work of an 11-member international team led by Australian ecologist Erick Lundgren of the University of Technology, Sydney.
The authors pored over scientific literature; created a list of living and extinct herbivores over the last 126,000 years; and categorized them by their body size, anatomy, habitat, diet, and how their bodies digested the vegetation. Then they compared their lifestyles in overlapping regions.
Carroll, affiliated with the UC Davis Department of Entomology and Nematology, said one of the studies dealt with the abandoned hippos of Colombian drug lord Pablo Escobar (1949-1993), who purchased a male and three females in the 1980s from a California zoo and kept them in fields along the Magdalena River, northwestern Colombia. Without humans and other predators decimating them, the population today is 80 and is expected to reach 800 to 5000 by 2050.
The out-of-place hippos may be filling the exotic roles of extinct massive animals, such as giant llamas and rhinoceros-sized relatives, the ecologists said.
Said Carroll: “That paleontological analysis found that, amazingly, introduced herbivores– including Pablo Escobar's escaped Colombian hippos– often match the functional traits of extinct natives better than do those missing species' closest living native relatives. In this way, the ‘out-of-place' make the world more similar to the pre-extinction past. The ‘shoot-first- and-ask-questions later' approach as a maxim is as reckless as it sounds, and it's not going to sustain our life-saving drugs, nor the species we revere or ecosystems we rely on, into the future.”
“Many introduced herbivores restore trait combinations that have the capacity to influence ecosystem processes, such as wildfire and shrub expansion in drylands,” the team wrote.
As for feral hogs in North America, Carroll said their rooting increases tree growth and attracts bird flocks, like the ecological work of their extinct ancestors. Likewise, the feral horses and burros, known for their well-digging behavior, are replacing the original American horses, which went extinct 12,000 years ago.
In their abstract, the authors pointed out that humans “have caused extinctions of large-bodied mammalian herbivores over the past 100,000 years, leading to cascading changes in ecosystems. Conversely, introductions of herbivores have, in part, numerically compensated for extinction losses. However, the net outcome of the twin anthropogenic forces of extinction and introduction on herbivore assemblages has remained unknown. We found that a primary outcome of introductions has been the reintroduction of key ecological functions, making herbivore assemblages with nonnative species more similar to preextinction ones than native-only assemblages are. Our findings support calls for renewed research on introduced herbivore ecologies in light of paleoecological change and suggest that shifting focus from eradication to landscape and predator protection may have broader biodiversity benefits.”
Carroll, who also co-led an author group of the newly published “Coevolutionary Governance of Antibiotic and Pesticide Resistance” in the journal Trends in Ecology, said that the publications together “address both sides of the human-environment co-existence issue.”
“Reading the titles, you might not expect these two studies are two sides of the same coin,” Carroll said, “but for me they address both sides of the human-environment issue that most compels me: How can we create more workable, productive and respectful long-term relationships with other species? To help think about this as an evolutionary biologist, I divide the key challenges of human interactions with Nature into those that arise from competitor and parasite species that adapt too quickly for us to control, and those that arise in in our efforts to protect more valued species– like endangered large mammals– that adapt too slowly to survive human impacts.”
“Pesticide and drug resistance are nature's predictable resilience to our reliance on an escalating war of toxic eradication,” Carroll commented. “A broader understanding shows how we can develop our own behavior to instead cultivate susceptibility to control in species we fight, using both new and known practices for improved sanitation, locally diversified agriculture, and eating lower on the food chain to inflect their evolution in a positive direction. Similarly, after millennia of driving much of the Earth's giant mammal community to extinction, we need to step back from our reflex to extinguish the errant survivors to preserve a modern sense of what's natural, without stopping to consider how these new neighbors (commonly fading from their native lands) may restore ancient ecological functions our own ancestors extinguished not so long ago.”
Carroll emphasized that “neither of these studies dismisses the serious problems irruptive populations can cause for meeting our food, health and environmental needs, nor seeks to oversimplify complex challenges. But it's actually important to work against being limited by prejudicial generalizations that lead us to sort other species into ‘good' versus ‘bad' bins. This is a sensibility that ecologists in particular should strive to cultivate. To continue to feed and shelter ourselves and remain healthy while sharing the Earth with other species, we need to develop methods that respect the tremendous information and know-how inherent in each species. I want us to do a much better job of working with that intrinsic functional diversity and adaptive potential as our best resource for advancing resilient and biodiverse ecological systems into the future.”
Carroll and his wife, UC Davis ecologist Jenella Loye, own Carroll-Loye Biological Research, Davis. They engage in public health and environmental entomology and natural product development.
(Editor's Note: The lead author of Coevolutionary Governance of Antibiotic and Pesticide Resistance is Peter Søgaard Jørgensen, who during his University of Copenhagen graduate work, spent a year at Davis studying soapberry bug host adaptation in California with Scott Carroll. The duo led the multi-year international "Living with Resistance" pursuit at the National Science Foundation's National Socio-Environmental Synthesis Center. Carroll served as the senior author.)
Community ecologist Rachel Vannette, assistant professor, coordinated the seminars. Credit: Videos uploaded to the website, thanks to Hyun Suk Shin and George Terry.
Fall Quarter, 2019
Sept. 25, 2019
James Nieh, professor, Section of Ecology, Behavior and Evolution, Department of Biological Sciences, UC San Diego
Topic: "Animal Information Warfare: How Sophisticated Communication May Arise from the Race to Find an Advantage in a Deadly Game Between Honey Bees and their Predators" (See lab website)
Host: Brian Johnson, associate professor, Department of Entomology and Nematology
Link to Seminar
Nathan Schroeder, assistant professor, Department of Crop Sciences, University of Illinois, Urbana-Champaign
Topic: "Endless Worms Most Beautiful"
Host: Shahid Saddique, assistant professor, Department of Entomology and Nematology
Link to Seminar
John Mola, doctoral candidate, Neal Williams lab, Graduate Group in Ecology
Exit seminar: "Bumble Bee Movement Ecology and Response to Wildfire." Mola specializes in bee biology, pollinator ecology and population genetics.
Host: Neal Williams, professor, Department of Entomology and Nematology
Link to Seminar
Rebecca Irwin, professor of applied ecology, North Carolina State University, Raleigh, N.C.
Topic: "The Role of Floral Traits in Pollination and Bee Disease Transmission." She specializes in the ecology and evolution of multiple-species interactions, pollination biology, and species invasions
Host: Rachel Vannette, assistant professor, Department of Entomology and Nematology
Link to Seminar
Julián Hillyer, director of the program in career development and associate professor of biological sciences, Vanderbilt Institute for Infection, Immunology and Inflammation, Nashville, Tenn.
Topic: "Not So Heartless: Functional Integration of the Immune and Circulatory Systems of Mosquitoes"
Host: Olivia Winokur, graduate student, Chris Barker lab
Link to Seminar
Takato Imaizumi, professor, Department of Biology, University of Washington, Seattle
Topic: "Circadian Timing Mechanisms in Plant-Pollinator Interaction"
Host: Joanna Chiu, associate professor and vice chair of the Department of Entomology and Nematology
Link to Seminar
Don Cippollini, director of environmental sciences and professor, Department of Biological Sciences, Wright State University
Topic: "The Potential for Host Switching via Ecological Fitting in the Emerald Ash Borer-Host Plant System"
Link to Seminar
Winter Quarter, 2019-2020
Dec. 4, 2019
Jackson Audley, doctoral candidate who studied with the late Steve Seybold
Topic: "Semiochemical Interruption of Host Selection Behavior of the Invasive Walnut Twig Beetle, Pityophthorus juglandis."
Link to Seminar
Wednesday, Jan. 8, 2020
Karen Menuz, University of Connecticut, Storrs
Topic: "Molecular Basis of Insect Olfaction"
Host: Walter Leal, distinguished professor, Department of Molecular and Cellular Biology and a former chair of the entomology department
Link to seminar
Wednesday, Jan. 22
Sebastian Eves-van den Akker, University of Cambridge, UK
Topic: Effector Gene Birth in Plant-Parasitic Nematodes: Furnishing the Immunity and Development-Altering 'Tool Box'
Host: Shahid Siddique, assistant professor
Link to Seminar
Wednesday, Jan. 29
Elizabeth Crone, Tufts University, Medford, Mass.
Topic: "Why Are Monarch Butterflies Declining in the West?"
Hosts: Neal Williams, professor; Rachel Vannette, assistant professor
Link to Seminar
Wednesday, Feb. 5
Andrew Young, postdoctoral scholar at California Department of Food and Agriculture, Pest Diagnostic
Topic: "The Natural History of Syrphidae: From Pollinators To Parasitoids"
Host: Lynn Kimsey, professor and director of the Bohart Museum of Entomology
Link to seminar
Wednesday, Feb. 19
Mercedes Burns, University of Maryland, Baltimore County
Topic: "Reproductive Diversity And Sexual Conflict: Opilionid Mating From The Female Perspective"
Host: Jason Bond, professor and Schlinger Chair in Insect Systematics
Link to Seminar
Wednesday, Feb. 26:
Faculty Flash Talks (featuring series of faculty members, including Rachel Vannette, Ian Grettenberger, Shahid Siddique, Geoffrey Attardo, Jason Bond)
Link to Seminar
Wednesday, March 4
Brendon Boudinot, doctoral candidate, Phil Ward lab, exit seminar
Topic: "Morphology and Evolution of the Insects, and the Ancestors of the Ants"
Host: Phil Ward, professor
Link to Seminar
Wednesday, March 11
Mary Salcedo, postdoctoral researcher, Virginia Tech
Topic: "Hydraulics in an Insect Wing: How Venation Pattern Affects Circulation"
Host: Rachel Vannette, assistant professor
Link to Seminar
It's somewhat like that when plant-parasitic nematodes (microscopic round worms) play “chemical hide and seek” with their plant host, says plant pathologist Shahid Masood Siddique, an assistant professor in the UC Davis Department of Entomology and Nematology.
“The success of plant-parasitic nematodes depends on their ability to locate a suitable host in the soil,” says Siddique, corresponding author of the newly published Spotlight article, “Chemical Hide and Seek: Nematode's Journey to Its Plant Host,” in the journal Molecular Plant.
Nematodes can be deadly to plants, not only because of the direct damage they cause (they extract water and nutrients from their hosts such as wheat, soybeans, sugar beets, citrus, coconut, corn, peanuts, potato, rice, cotton and bananas) but the role of some species as virus vectors.
“Plant-parasitic nematodes are among the most destructive agricultural pests, causing more than $100 billion in losses per year in the United States,” Siddique said, noting that nematodes are especially damaging to potato, soybean and wheat crops.
Although the success of nematodes depends on their ability to locate a suitable host in the soil, what attracts them to their host “has largely remained unknown,” wrote the four-member UC Davis team of Siddique, Natalie Hamada, Henok Zemene Yimer and Valerie Williams. “Recent studies have revealed that host-seeking by nematodes is a complex process that involves multiple stages in the interaction.”
“Most damage is caused by a small group of root-infecting sedentary endoparasitic nematodes including cyst nematodes and root-knot nematodes (RKNs),” the team of UC Davis researchers wrote in their abstract. “Second stage juveniles (J2s) of plant-parasitic nematodes hatch from eggs into the soil and localize to the roots of host plants. The success of these non-feeding J2s depends on their ability to locate and infect a suitable host.”
For eight decades, scientists have researched the attraction of plant-parasitic nematodes to the host root, ever since the pioneering Maurice Blood Linford (1901-1960) of the University of Illinois, Urbana, Ill., observed in 1939 that the larvae of root-knot nematodes congregate in the cell elongation region behind the root cap.
“Both volatile and soluble components in the rhizosphere have been shown to influence nematode movement,” the UC Davis researchers wrote. “Methyl salicylate, a volatile chemical root signal, has been demonstrated to be a strong root attractant for RKN towards several Solanaceous plants (nightshade family). The non-volatile tomato root exudate quercetin was shown to elicit concentration dependent attraction or repulsion effect against Meloidogyne incognita to host root. Three recent studies have revealed that the recognition of and response to hosts by infective juveniles is a complex process that involves multiple stages in the interaction.”
Siddique focuses his research on basic as well as applied aspects of interaction between parasitic nematodes and their host plants. “The long-term object of our research is not only to enhance our understanding of molecular aspects of plant–nematode interaction but also to use this knowledge to provide new resources for reducing the impact of nematodes on crop plants in California.”
Entomologist Marlin Rice, a past president of the Entomological Society of America (ESA), penned the piece, titled "Bruce D. Hammock: Science Should Be Fun!"
Wrote Rice: "Bruce D. Hammock is widely known for his groundbreaking research in insect physiology, toxicology, pharmacology, and experimental therapeutics. Early contributions were in fundamental regulatory biology, development of both small molecules and recombinant viruses as environmentally friendly pesticides, and the application of accelerator mass spectrometry to biological science. His laboratory pioneered the use of immunoassay for the analysis of human and environmental exposure to pesticides and other contaminants.His laboratory provides graduate training that is diverse in disciplines and research areas. He recently formed a company, EicOsis, to develop an orally active non-addictive drug for inflammatory and neuropathic pain for humans and companion animals."
Hammock, who joined the UC Davis faculty in 1980 from UC Riverside, has directed the UC Davis Superfund Research Program (funded by the National Institutes of Health's National Institute of Environmental Health Sciences) for nearly four decades. He is a member of the National Academy of Sciences, and a fellow of the National Academy of Inventors and ESA.
A native of Little Rock, Ark., Bruce received his bachelor's degree in entomology (with minors in zoology and chemistry) magna cum laude from Louisiana State University, Baton Rouge, in 1969. He received his doctorate in entomology-toxicology from UC Berkeley in 1973 with John Casida at UC Berkeley. Hammock served as a public health medical officer with the U.S. Army Academy of Health Science, San Antonio, and as a postdoctoral fellow at the Rockefeller Foundation, Department of Biology, Northwestern University, Evanston, Ill.
Read the feature story here.
Some Related Links:
- Bruce Hammock and EicOsis, Innovator of the Year
- Bruce Hammock Receives $6 Million Grant
- Bruce Hammock Water Balloon Battle: 15 Minutes of Aim
- Research Could Lead to Drug to Prevent or Reduce Autism, Schizophrenia
- Hammock Lab Union Draws 100 Scientists from 10 Countries
- Bruce Hammock: Scientist Extraordinaire
(Editor's Note: Thanks to Lisa Junker, ESA's director of publications, communications and marketing, who reached out to "our publishers at Oxford" to grant free community access to this feature story in American Entomologist)
Before accepting her UC Davis appointment, Meineke served as a National Science Foundation postdoctoral fellow at the Harvard University Herbaria, where she studied how urbanization and climate change have affected plant-insect relationships worldwide over the past 100-plus years.
A native of Greenville, N.C., Emily received her bachelor of science degree in environmental science, with a minor in biology, in 2008 from the University of North Carolina, Chapel Hill, and then went on to obtain her doctorate in entomology in 2016 from North Carolina State University. Advised by Steven Frank and co-advisor Robert Dunn, she completed her dissertation on "Understanding the Consequences of Urban Warming for Street Trees and Their Insect Pests."
1. Please expand on the kind of research you do.
"Insects have eaten plants for around 400 million years. These interactions have given rise to most of terrestrial biodiversity. Over the past 12,000 years, humans have disrupted plant-herbivore relationships by building cities, domesticating crops, and changing the global climate."
"I investigate these disruptions, focusing on species that are of cultural importance, such as street trees, crops, crop wild relatives, and plants that support rare insect species. My work combines experiments, observations, citizen science, and biological collections to address key hypotheses in ecology."
2. What do you like best about your work?
"I love discovery, the moment when you as a scientist know something that no one else knows. I love passing that experience on to students. I also love that my work reflects my personal values. Biodiversity is critically important, and the fact that I get to study it for a living is a real privilege."
3. How did you get interested in entomology? Can you recall an occasion that sparked your interest?
"I have no idea, honestly. I never had an insect collection as a kid, and I was equally interested in all living things, from my family's pets to the toads that lived in my backyard. At some point after my undergraduate education, I realized that insects are both invisible to us most of the time and are incredibly present in our lives and imaginations. Ecologically, because they are small in size, they can seem unimportant because we are biased to think creatures our size or larger are important, but insects are really the little things that run the world."
4. How would you describe yourself?
"I'm a pretty serious person who is always working to be more light-hearted. I am both easily discouraged and tenacious. I would describe myself as creative and am drawn to diversity in all forms."
5. What drew you to UC Davis?
"When I visited, I got the feeling that UC Davis encourages creativity while valuing research that produces real solutions. When I interviewed here, I felt I would be able to be myself as a researcher and that my fellow faculty would support that. On top of that, UC Davis is such an established institution with great resources in a beautiful part of the world. I can't think of a better place to be."
6. What do you like to do in your leisure time?
"All I really ever want to do is eat and spend time with people I love. 'People' includes my two dogs, who rule the house."
9. What would people be surprised to know about you?
"I have a hidden talent. I can make very realistic cat meows. I can fool anyone's cat and most humans."
In addition to her NSF Postdoctoral Research Fellowship, she received a number of other honors, including Student Appreciation for the Biology of Insect Pests Award; Garden Club of America Urban Forestry Fellowship; and the EPA Science to Achieve Results (STAR) Fellowship.
A member of the Entomological Society of America (ESA), Ecological Society of America and the Botanical Society of America, she has presented talks across the continent, as well as in Finland, Spain, Canada, France and Denmark. She delivered a presentation at the 2016 International Congress of Entomology in Orland, Fla., and at ESA's national and regional meetings.
Meineke has published her work in Ecological Monographs, Ecology and Evolution, Journal of Applied Ecology, and the Journal of Urban Ecology, among others.
The Boston Globe featured her research in a news story published Oct 11, 2018: "Rising Temperatures May Cause Insects to Eat More Plants, Harvard Study Says"
Nature journal featured her in a research highlights piece, "Warmer Forests Store Less Carbon," published Oct. 12, 2016
Los Angeles Times spotlighted her in its Oct. 6, 2016 piece, "As Cities Get Warmer, These Trees Lose Some of their Ability to Take Carbon Out of the Atmosphere."