- Author: Kathy Keatley Garvey
Food ought to be incorporated as an integral part of our school curricula, says UC Davis agricultural entomologist Christian Nansen, an associate professor in the Department of Entomology and Nematology.
Yes!
And he welcomes teachers' involvement in this important project. (Teachers, be sure to contact him! More at the end of this blog.)
Nansen, in a newly published article on “The School of Food” in Futurum, advocates that all school curricula be “rooted in a single dominator: food.”
Biology, ecology and environmental science should be “taught based on subjects related to the growth of plants and animals,” Nansen writes. Literature, history, sociology and humanities should focus on “the importance of food concepts, like ‘breaking bread,' feasts and banquets.”
“What I am proposing here is already being done, in part, as individual initiatives and projects,” he writes. “For example, many schools have a butterfly garden, biology labs keep colonies of insects, students grow some vegetables and have a few livestock animals. In some schools, students learn how to eat and cook healthy food.”
Futurum is a website geared toward students and teachers to become inspired and interested in science. It focuses on research, analysis and insights.
Nansen, whose research interests include insect ecology, integrated pest management, and remote sensing, says that such a focus on food “would strengthen, not weaken, the academic rigor that could be delivered to students of all age groups.”
“That is, ‘food' as an educational denominator can be taught and approached with multiple goals in mind, and these would be similar to the current distinctions between practical and more theoretical classes. By engaging with students through the prism of food, we can make math, physics, history, biology, literature--all these topics more relevant to students and make the teaching more interactive and challenge-based.”
Nansen acknowledges that it is crucial that schools teach students about traditional subjects and provide them with essential skill sets regarding problem solving, critical thinking and basic knowledge, but that that students “can all be taught very effectively through an underlying emphasis on food.”
For example, he mentions that students of all ages can grow crop plants in small pots inside a classroom or outside (small plots and roof gardens), “and study growth as a function of time and growing conditions.” More advanced practical tasks could include developing irrigation systems, and plant and animal breeding programs.
Another example: for engineering, computer sciences and food production, students could delve into solar panels, rainwater catchment systems and water recycling methods. At the more advanced level, they could integrate robotics and machine learning system.
Nansen, linking chemistry with cooking, comments: “Cooking is nothing more and nothing less than applied chemistry. How does the pickling of vegetables work? What is happening when cream is whipped? What happens to food during heating and/or frying? Salting olives, fish and other types of meat has been practiced for thousands of years—how does this means of preserving food actually work?”
In his article, Nansen also explains how food can be incorporated in such subjects as humanities, human history, social studies and math.
Eating has changed over time, the professor acknowledges, “and it varies among countries and cultures, meaning that not all students view food in the same way.” But teachers can capitalize on diversity in the classroom, he relates. They can also address “societal challenges, such as obesity” and elevate levels of empowerment related to stresses, such as fear.
In the article, Nansen shared a project he assigned to his 11-year daughter, Molly, during the sheltering-in requirements: “How much cabbage would be needed to meet the Vitamin K requirements for her entire class for a whole year?”
In addition to learning about the metric system, using Excel spread sheets, regression analyses and calculus, Molly investigated websites and came to several conclusions:
- A person can harvest about 3 kg per m2 (kilograms per square meter)
- A student her age has to have 105 grams of cabbage to meet daily vitamin K requirements
In addition, she created a cabbage-muffin recipe and calculated she would need to eat four muffins per day to meet the daily Vitamin K requirements. She also calculated she would need 2,291 m2 to grow enough cabbage to meet the daily vitamin K requirement for her entire school. It is age-dependent, so that was a bit tricky to figure out.
And lastly, using Google Earth, Molly suggested where to place the cabbage field next to her school. (Her entire project, including the recipe she created, is online as a sidebar.)
Virtual Youth Summit on Food and Education 2021
Nansen said he seeks contact with teachers and headmasters "interested in pursuing this approach at some level at their school."
"The idea is now to take this several steps further, through collaboration with teachers and their students, and set up a web-based platform to host an annual virtual youth summit on food and education!" he said. "That is, groups of students, in collaboration with their teachers and as part of course curricula, produce a 3-5 minute video describing a particular project they have executed. These videos would then be shown at the virtual youth summit, and we will organize review panels of students, teachers, and scientists to comment on the videos. These video projects would be divided into age groups and topics – still to be determined."
"I am hoping that we will be able to create a very special category of video projects describing two schools (have to be on separate continents) doing a project together," Nansen said. "As a start, we are pursuing the potential of a school in California working with a school in Uganda… which would be awesome!"
"We may be able to obtain corporate sponsorships and therefore be able to offer prizes/awards to participating schools, teachers and student groups. With corporate sponsorships, we may also be able to offer logistical support to schools – computers, software licenses (to create videos), basic lab supplies and equipment to conduct experiments.'"
"Just imagine a school being able to put on its website that a group of students competed in the Virtual Youth Summit on Food and Education 2021 and was selected as one of the winners! Students can put this experience on their resume when they later apply to university or jobs. Teachers can include this in their evaluation dossiers."
"Initially, we need to identify teachers interested in joining this effort--ideally teachers from multiple countries," Nansen related. "Once we have 5-10 teachers committed, then we can start putting together the virtual platform and invite schools and teachers more broadly." School teachers and others potentially interested in getting involved can contact him at chrnansen@ucdavis.edu.
- Author: Kathy Keatley Garvey
But newly published research by UC Davis agricultural entomologist Christian Nansen and insect physiologist Michael Strand of the University of Georgia reveals a new, non-destructive and quite accurate method to characterize physiological responses to parasitism: proximal remote sensing or body reflectance response data.
They published their research, “Proximal Remote Sensing to Non-Destructive Detect and Diagnose Physiological Response by Host Insect Larvae to Parasitism,” Dec. 4 in the journal Frontiers in Physiology.
Nansen, first author of the paper and an associate professor in the UC Davis Department of Entomology and Nematology, specializes in insect ecology, integrated pest management and remote sensing. Strand, a professor of entomology at the University of Georgia, is an international authority on the physiology of insect parasitism.
The scientists studied two common parasitic wasps or parasitoids, Microplitis demolitor, and Copidosoma floridanum, which lay their eggs in the larval stages of the soybean looper moth, Chrysodeixis includens. The pest, found throughout much of North and South America and elsewhere, feeds on soybeans.
“Based on reflectance data acquired three to five days post-parasitism, all three treatments (control larvae, and those parasitized by either M. demolitor or C. floridanum) could be classified with more than 85 percent accuracy,” they wrote.
Due to parasitism-induced inhibition of growth, “it's easy to differentiate soybean loopers parasitized by M. demolitor from non-parasitized larvae as long as the developmental stage of the host larva is known,” they said. In addition, a single M. demolitoroffspring emerges from the host larva 7-9 days post-parasitism to pupate, while non-parasitized larvae continue to increase in size to the final instar.
Copidosoma floridanum minimally alters host growth until late in the final instar, when thousands of wasp progeny complete their development. This wasp is known for having the largest recorded brood—3,055 individuals--of any parasitoidal insect.
The researchers said that the accuracy rate of more than 85 percent holds promise. “The hyperspectral proximal imaging technologies represent an important frontier in insect physiology, as these technologies can be used non-invasively to characterize physiological response across a range of time scale factors, such as minutes of exposure or acclimation to abiotic factors, circadian rhythms, and seasonal effects. Although this study is based on data from a host-parasitoid system, results may be of broad relevance to insect physiologists.”
Both of the wasps they studied are idiobionts and endoparasitoids.
Nansen noted that “many species of minute wasps are parasitoids of eggs and larvae of other insects, and parasitism represents one of the most extreme life strategies among animals”
“Living inside the body of another animal,” he said, “poses a series of non-trivial challenges, including how to overcome/suppress the defense response by the host; how to obtain oxygen; how to feed on the host without killing it--because once the host is dead, then microbial organisms and general decomposition will make the host body unsuitable--and how to manage waste.”
Nansen likened the developing parasitoids to astronauts flying in a space capsule. “A developing parasitoid faces a long list of serious practical challenges, so the evolutionary selection pressure has been immense and lead to some of the most extreme cases of co-evolution.”
And those soybean loopers? Those major pests of soybeans? Thanks to this research, we now know more about physiological responses to parasitism--and there's more to come. (We're also admiring the amazing photography of Jena Johnson!)
As the researchers said: "The hyperspectral proximal imaging technologies represent an important frontier in insect physiology."
- Author: Kathy Keatley Garvey
If you've been following the innovative work of agricultural entomologist and remote sensing technology researcher Christian Nansen, associate professor of entomology at the University of California, Davis, you can.
Using Skittles (candy), magnolia leaves, mosquito eggs and sheets of paper, Nansen explored how light penetrates and scatters--and found that how you see an object can depend on what is next to it, under it or behind it.
He published his observations in a recent edition of PLOS ONE, the Public Library of Science's peer-reviewed, open-access journal. He researches the discipline of remote sensing technology, which he describes as “crucial to studying insect behavior and physiology, as well as management of agricultural systems.”
Nansen demonstrated that several factors greatly influence the reflectance data acquired from an object. “The reflected energy from an object--how it looks-- is a complex cocktail of energy being scattered off the object's surface in many directions and of energy penetrating into the object before being reflected,” Nansen pointed out. “Because of scattering of light, the appearance--or more accurately the reflectance profile--of an object depends on what is next to it! And because of penetration, the appearance of an object may also be influenced by what is behind it!”
“The findings are of considerable relevance to research into development of remote sensing technologies, machine vision, and/or optical sorting systems as tools to classify/distinguish insects, seeds, plants, pharmaceutical products, and food items.”
In the PLOS ONE article, titled “Penetration and Scattering—Two Optical Phenomena to Consider When Applying Proximal Remote Sensing Technologies to Object Classifications,” Nansen defines proximal remote sensing as “acquisition and classification of reflectance or transmittance signals with an imaging sensor mounted within a short distance (under 1m and typically much less) from target objects.”
“Even though the objects may look very similar--that is, indistinguishable--to the human eye, there are minute/subtle differences in reflectance in some spectral bands, “ Nansen said, “and these differences can be detected and used to classify objects.”
With this newly published study, Nansen has demonstrated experimentally that imaging conditions need to be carefully controlled and standardized. Otherwise, he said, “penetration and scattering can negatively affect the quality of reflectance data, and therefore, the potential of remote sensing technologies, machine vision, and/or optical sorting systems as tools to classify objects. “
Nansen described the rapidly growing number of studies describing applications of proximal remote sensing as “largely driven by the technology becoming progressively more robust, cost-effective, and also user-friendly.”
“The latter,” he wrote, “means that scientists who come from a wide range of academic backgrounds become involved in applied proximal remote sensing applications without necessarily having the theoretical knowledge to appreciate the complexity and importance of phenomena associated with optical physics; the author of this article falls squarely in that category!”
“Sometimes experimental research unravels limitations and challenges associated with the methods or technologies we use and thought we were so-called experts on,” Nansen commented.
Nansen, who specializes in insect ecology, integrated pest management, and remote sensing, joined the UC Davis faculty in 2014 after holding faculty positions at Texas A&M, Texas Tech and most recently, the University of Western Australia.
- Author: Kathy Keatley Garvey
They can also do something else.
Basically, if you're a plant and an insect is attacking you, you can communicate your stress to nearby plants as a way to alert them about potential danger--very similar to how animals communicate or respond to predators, according to UC Davis agricultural entomologist Christian Nansen of the Department of Entomology and Nematology.
In groundbreaking research published in the journal Plant Methods, Nansen and his team of six colleagues from Brazil discovered that plant-plant communication causes physiological changes in plants and these subtle changes can be detected via analyses of leaf reflectance or hyperspectral imaging. The article is titled “Hyperspectral Imaging to Characterize Plant-Plant Communication in Response to Insect Herbivory."
The growing knowledge about plant-plant communication and about plants' ability to assess their environment has led to concepts like “plant neuro-biology” and “plant behavior,” said Nansen, an associate professor who centers his research on host plant-stress detection, host selection by arthropods, pesticide performance, and use of reflectance-based imaging in a wide range of research applications.
“We know that plants don't have a neural system or brain,” said Nansen, “but respected scientists are studying plants as if they did, as if plants are able to assess conditions in their environments, and they can adapt/respond to those conditions.”
“In studies of plant stress signaling, a major challenge is the lack of non-invasive methods to detect physiological plant responses and to characterize plant-plant communication over time and space.” Nansen pointed out. He described the research as “initial evidence of how hyperspectral imaging may be considered a powerful non-invasive method to increase our current understanding of both direct plant responses to biotic stressors but also to the multiple ways plant communities are able to communicate.”
The UC Davis entomologist and his team used leaf reflectance data to detect and characterize plant responses to stressors, knowing that induced stress interferes with photosynthesis, chemical composition and physical structure of the plant, thus affecting the absorption of light energy and altering the reflectance spectrum of the plants.
“For several decades, it has been known that plants communicate – both among individuals of the same species and across species,” Nansen related. “That is, volatiles emitted by one plant can be received by another plant and trigger different physiological responses. It is also well-documented that plants communicate via roots, and sometimes the roots from different plants are brought together in a network of communication and exchange of nutrients through symbioses with mychorriza (soil fungi).”
Of the Nansen study, Karban said: "This study describes a technique that may provide a relatively quick and inexpensive way to evaluate levels of resistance in plants. If these results are repeatable by other workers in other systems, they will provide a very valuable tool for researchers and growers."
Both Karban and Nansen contributed chapters to the recently published book, The Language of Plants (University of Minnesota Press). The book explores "the idea that plants can think, feel, and communicate as a way of reconfiguring our relationship with the natural world," according to editors Monica Gagliano, John C. Ryan, and Patrícia Vieira.
"Within the last decade or so, extremely cutting-edge research in the field of plant-plant communication has been done by people like Dr. Monica Gagliano of the University of Western Australia," Nansen said. "She has elegantly demonstrated that plants can respond not only to aerial volatile compounds and root secretions but also to sound."
For the research project, Nansen and his team decided to conduct “a very simple experiment with corn plants and stink bugs.” They planted corn plants in separate pots or two in one pot. They subjected some plants to herbivory by stink bugs, while other plants served as control plants.
The scientists collected two types of data: phytocompounds (stress hormones and pigments) and leaf reflectance data (proximal remote sensing data).
“Our research hypothesis was that insect herbivory causes changes in leaf phytocompound levels, and these physiological defense responses are associated with detectable changes in phytocompound levels and in certain spectral bands of leaf reflectance profiles,” Nansen pointed out. As a secondary hypothesis, the researchers predicted that plant-plant communication (from plant with herbivory to an adjacent control plant without herbivory) will elicit both a change in phytocompound composition of leaves and also cause a corresponding change in leaf reflectance.
The result: The first published study, in which comprehensive phytocompound data have been shown to correlate with leaf reflectance. In addition, it is the first published study of leaf reflectance in plant-plant communication.
Nansen and co-author Leandro do Prado Ribeiro of the Research Center for Family Agriculture, Research and Rural Extension Company of Santa Catarina, Brazil, conceived and designed the experiments. The Brazilian National Counsel of Technological and Scientific Development provided partial financial support. Co-author Marilia Almeida Trapp received financial support from a Capes-Humboldt Research Fellowship.
- Author: Kathy Keatley Garvey
In his paper, titled “Edge-Biased Distributions of Insects: A Review,” Nguyen reviewed how many species of insects show a definite preference for living on the edges of fields and orchards.
This phenomenon can lead to more accurate monitoring and better pest management tactics, said Nguyen and co-author Nansen.
The paper indicates that “the prevalence of such edge-biased distributions has considerable implications for how to sample and monitor insects, and it also suggests that in many cases pest management tactics, such as, releases of natural enemies or insecticide applications can be spatially targeted to field edges.”
Nguyen traced the history of edge-based distribution of insects in agricultural systems to a study on black bean aphids led by British entomologist C. G. Johnson and published in 1950 in the Annual of Applied Biology. The aphids, major pests of sugar beet, bean and celery crops, spread from the field edges to within, but the edges remained the areas of highest aphid density.
Nguyen also called attention to scientific studies that found that wild bees in high bush blueberry were more prevalent along the edges of orchards, and that the density of the pest, Asian citrus psyllid, prevailed more at the edges of citrus groves than within.
Nansen praised Nguyen's work as outstanding. “Sometimes we professors are fortunate enough to interact with undergraduate students who – even with English not being their first language – possess keen abilities to describe a scientific problem or phenomenon in clearly articulated scientific writing, and Derrick is a great example of that!”
“He started writing drafts of this review article about six months before he started as a graduate student,” Nansen said. "This review article is an example of how we can use writing of review papers as a tool to engage with undergraduate students before they start their thesis projects.” Professor Jay Rosenheim of the UC Davis Department of Entomology and Nematology also helped with the drafts.
“We are supposed to focus more and more on ‘diversity' and here we have an undergraduate from Singapore publishing in a very prestigious journal,” Nansen added.
The UC Davis scientists suggest that mathematical modeling approaches can partially explain edge-biased distributions but “that abiotic factors, crop vegetation traits, and environmental parameters are factors that are likely responsible for this phenomenon.”
They advocate more research, especially experimental research, “to increase the current understanding of how and why edge-biased distributions of insects are so widespread.”
“In my opinion, discussions about edge-biased distribution of insects tend to be entomocentric; much emphasis is often put on the insects themselves,” Nguyen commented. “However, agricultural insect pests are dependent on their host plants for survival. Interestingly, it has been shown in various systems that agricultural crops also display edge effect as well. Therefore, through my review, I would like to bring attention to this correlation and propose insect-plant interactions as a potential explanation of edge effect and broaden the discussion about this widely observed but insufficiently understood phenomenon.”
Nguyen received a bachelor's degree in plant sciences from UC Davis in December 2017, graduating with highest honors. A high-achieving scholar, he was on the dean's honor list, College of Agricultural and Environmental Sciences, every quarter since the fall of 2015. He enrolled in the UC Davis graduate student program in entomology in January 2018.
“I am interested in IPM, insect behavior and insect ecology, and greenhouse production of leafy vegetables,” he said. “Currently I am working on projects that explore the potentials of hyperspectral imaging technology as early detection tools for pest infestation and insect host selection based on the framework of preference-performance hypothesis. As my research model, I focus on the interactions between vegetables (bok choy and spinach) and their insect pests (leafminers and armyworms).
Nguyen served as an assistant training officer with the Singapore Armed Forces (SAF) from April 2014 to March 2015. For his studies at UC Davis, he received a 2015-2019 undergraduate and graduate scholarship sponsored by Agri-Food and Veterinary Authority of Singapore.
“For my career plan, since I am currently sponsored by AVA, I will be working for them for six years upon my graduation,” Nguyen said. “In the long term, I am interested in doing a Ph.D in imaging technology for pest detection, plant health status analysis and food quality analysis.”
Well done.
