Stanley Faeth - US grants

This research will test the effects of previous folivory on subsequent folivorous insect species via alterations in the shared host plant, particularly alterations in phenology. Specific factors hypothesized to influence such interactions, including extent of folivory (partial vs. complete consumption of leaves), amount of partial damage an dits effect on the third trophic level (natural enemies), timing of folivory and long-term effects of folivory, will be examined. These factors will be tested in a series of observations and manipulative experiments involving leafchewers (early-season feeders) and leafminers (late-season feeders) on the Emory oak, Ouercus emoryi. Preliminary evidence suggests such factors can change the outcome of interactions between seasonal folivores, and thus influence population dynamics and organization of folivorous insect communities. The project will quanfify phenological and chemical changes associated with varying folivory and their effects on colonization, local extinction, survival, causes of mortality, and fecundity of the leafmiing species on Emory oak. Although accumulating evidence indicates that plants change following folivory, the precise effects on subsequent insect species are equivocal. Yet such information is crucial in unerstanding how plant-mediated interactions influence population dynamics and organization of folivorous insect species sharing host plants.

The goal of the proposed research is to test the role of microorganisms in mediating interactions among phytophagous insects, their host plants and their natural enemies. Specifically, the proposed research will determine how endophytic fungi (fungi that produce asymptomatic infections within plant tissues) affect colonization, dispersion, and population dynamics of leafmining and leafchewing insects that feed on a common host plant, Emory oak. Although endophytic fungi are thought to be plant mutualists by deterring other herbivores, accumulating evidence suggests that their effects on phytophagous insects are highly variable. The proposed research will test the direction and magnitude of these effects through a series of field and laboratory experiments and observations. Ecologists have recently recognized that the pervasive effects of microorganisms such as endophytic fungi may alter conventional theories of phytophagous insect - host plant - natural enemy interactions. By rigorously examining the effects of endophytic fungi, the proposed research will test and modify these conventional theories.

9317340 Grimm

This proposal is submitted under a special pilot program, Undergraduate Mentorships in Environmental Biology. The four year program will offer undergraduate students first hand experience in carrying out ecological research under the mentorships of six active research ecologists. We will aggressively seek to involve groups traditionally under represented in environmental biology, includi ng trainees of Latino, American Indian, and African American backgrounds as well as a number of non minority students. This effort will be aided considerably by close coordination with existing programs that target these minority groups at ASU. The program is a specialized educational track consisting of an integrative first year seminar, early exposure to advanced courses, research involvement at the outset of students' college careers, and continued follow up and support of individual students as they make plans for graduate school and future careers. Careful documentation of the program's successes and failures, support from other research experience programs targeting more advanced undergraduate students, and placement of students in individual laboratories will facilitate the entry of alumni and alumnae of this program into research careers in environmental biology.

Faeth This project comprises a series of field and laboratory observations and experiments to examine the role of endophytic fungi in deterring herbivory on Arizona fescue and enhancing its competitive ability against other plant species. The investigators are also determining the costs to the plant (in terms of reproductive fitness) of the relationship with endophytic fungi under various environmental conditions. The investigators are also examining the effects of maternal (vertical) transmission of the endophytes on seed predation and seed dispersal by seed-harvesting ants. The results of this research have important implications for the role of microorganisms in dynamics of plant-animal interactions and the organization of plant communities. The results of this research have applications in conservation biology, rangeland management, and reclamation ecology. The re-establishment of native grasses in reclamation and range management efforts may be seriously affected by relationships with endophytes. These relationships may also affect native ungulates and introduced livestock.

Faeth 97 27020 Endophytic fungi frequently live intracellularly within the tissues of plants with little obvious indication of their presence. In grasses these symbionts have been thought to increase plant resistance to herbivory, resistance to drought, and the competitive abilities of some plants in their interactions with their neighbors. Despite the widespread occurrence of these associations, however, information on the nature of fungal-plant interactions remains limited. This project will continue investigations of the relationship between endophytic fungus, Neotyphodium, and Arizona fescue an economically important range grass in the southwest. An earlier series of experiments, funded by the Ecology program at NSF, failed to demonstrate that these fungi, provide any resistance to grazing by invertebrate herbivores, in contrast with widely held conventional wisdom that such a resistance is provided. Alternative hypotheses to be tested in this new work center on the observation that plants increase root biomass and, possibly, osmoregulatory efficiency when infected by fungi. It will examine the varying survival of seed, seedling, and mature-plant stages of fescue under different conditions of soil moisture and nitrogen along with fire frequency and intensity for different plant genotypes. It will employ a series of field and laboratory experiments to test the notion that the Neotyphodium-Arizona fescue mutualism is context dependent. It will also consider that fire may be an evolutionary factor that maintains these associations. The results of this work will increase the understanding of the role of microoganisms in plant-animal interactions, plant population dynamics and the organization of plant-microbe-herbivore communities. It will shed insight into the evolution, ecology and maintenance of mutualistic interactions. It will also provide useful information for the maintenance important southwestern grasslands.

A program is proposed to provide an multifaceted research and educational experience for undergraduate students in environmental biology. The program will attract freshman and sophomore students to experience environmental biology early in their academic careers. A diverse array of environmental biologists will serve as mentors for these students. Students will gain research experience in project ranging from hormonal control of mating behavior to the biogeochemistry of urban environments. Recruiting and retention efforts for this program will be focused on groups that are generally under represented in environmental biology. Participants are expected to include a mixture of Latino, American-Indian, and African-American students. The program will involve careful mentoring not only of students by faculty but by younger students by older students. Careful documentation of student participants will be used to assess and modify the program as a permanent university feature.

Project Summary

Endophytes are fungi that live internally in plants but do not cause disease. Instead, endophytes are thought to benefit the plant by increasing resistance to drought, herbivores, and seed predators, pathogens and root feeders and increasing germination rates, nutrient uptake, and competitive abilities. Endophytes are found in all plants, including agronomic crops and turf grasses. They are used in turf grasses to increase performance of grasses, but may also cause harm livestock because of their toxic effects. However, little is known about the role of endophytes in native grasses. The benefits of endophytes are often not the same as in agronomic grasses. Our research seeks to determine the costs and benefits of asexual, seed borne endophytes in the genus Neotyphodium in two widespread SW native grasses, Arizona fescue and sleepy grass. Our goals are to experimentally test the cost and benefits of Neotyphodium infection depending on plant and endophyte genotype and environment. We will implement two major field experiments that control plant genotype and endophyte infection, soil moisture levels and herbivory by invertebrates and vertebrates. Our results will provide insights into basic interactions between endophytes and their host grasses, and may have important applied aspects related to forage grasses.

Urbanization is the most rapidly increasing land use type worldwide. We already know that biodiversity is radically altered in cities. However, we do not know what factors control the trophic or feeding structure of urban communities, and how these controls differ from less human-dominated or natural environments. For example, reduction of predators in cities could mean that herbivores (consumers of plants) increase dramatically and are controlled only by resources or stress. Our research will determine the relative effects of resources, stress, and natural enemies (predator and parasites) in cities on herbivore and predator abundances and diversity, and plant biomass.

Our research addresses fundamental questions - How is trophic structure and dynamics influenced by urbanization and, are trophic dynamics different in cities than in less human dominated ecosystems? This research will provide insights into how food webs and their associated biodiversity and ecosystem services can be maintained in urban settings. This research is closely linked to educational and K-12 outreach programs (e.g., Ecology Explorers), as well as partnerships with state and local governments and businesses. Some of our experimental sites are K-12 schoolyards, where K-12 teachers and students will directly participate in the experiments and interact with ASU faculty and graduate students.

Hybridization between species is a well-known biological process that rapidly creates new species and varieties of living organisms. For example, approximately 95% of fern species and 70% of flowering plant species and have arisen from hybridization (combining genes from two species). Hybrid plants include important crop plants such as modern wheat. Many species of animals are also the result of hybridization between two parental species. Much less is known about hybridization between microbial species, although the ecological consequences can be dramatic. For example, the aggressive and pathogenic fungus that causes Dutch elm disease and devastated American forests resulted from hybridization of two benign fungal strains. This research studies the ecological effects of hybridization of a fungal endophyte that lives internally in both agronomic and native grasses. Endophytes are symbiotic fungi that live inside plants and do not usually cause disease. Instead, these endophytes improve growth, competitive abilities and resistance to herbivores that consume the plant. This research will examine how hybridization of the endophyte alters the growth, reproduction and survival of the grass in which it lives.

This research has important implications for the welfare of pasture, turf and native grasses, all of which are often infected with endophytes. Furthermore, hybridization opportunities have dramatically increased as microbes are transported globally by human activities. These microbial hybridization events may result in either positive or negative (e.g., pathogenic) effects on their hosts, including crops, humans and livestock. Understanding how hybrid microbial partners influence their native host grasses and agronomic crops is therefore essential.

Transforming Minds in a Transitioning Community


The GK-12 program at the University of North Carolina-Greensboro partners Fellows from several departmental graduate programs with teachers and students at three Guilford County Schools (one elementary, middle and high school in the same neighborhood) to form discovery teams to scientifically investigate the biological, health-related, and socioeconomic effects of changing land use patterns in the region. The research questions of the Fellows are linked to local neighborhood issues and larger historical changes in land use patterns. Although the research questions are focused on neighborhood and regional environmental issues, the scientific literacy skills acquired by program participants will enable them to critically and quantitatively address any scientific question or environmentally-related problem, ranging from local to global scales. Fellows and teachers will work in school-based teams on three primary tasks: the development and delivery of inquiry-based lesson plans, greater quality and quantity of differentiated instruction, and the creation of K-12 student teams to teach others science concepts and methods. Fellows will learn to communicate research to a wide variety of audiences, develop lesson plans, develop leadership skills, enhance their teaching capability, and engage in research activities with students. Teachers will integrate new research into their teaching and learning and take part in professional development on inquiry-based science instruction and working with diverse student groups. K-12 students will become engaged in new forms of science learning and research and will be exposed to a variety of STEM careers.

The project STAMPS: Science, Technology and Math Preparation Scholarships is serving the national interest by supporting academically talented and financially needy students, including minority, women and first-generation college students, in their efforts to complete their college degrees in the STEM disciplines (Natural, Physical, Earth and Computer Sciences). The project is providing financial, academic, mentoring and advising support to talented students in the STEM disciplines to increase their retention rates and better prepare students for science and technology-based careers or for advance study in professional (e.g., medical, dental, pharmacy, graduate) schools. By doing so, the project is increasing the pool of talented individuals for highly skilled jobs or careers in science and technology. The project is also developing best practices on how to support and train students for a skilled workforce that is shared with other universities.

STAMPS enrolls a diverse group of first year STEM students into a yearlong integrated science course, designed to create a cohort, supported by faculty and peer mentors and services. STAMPS students have opportunities for research, interacting with STEM speakers, travel, and facilitated shadowing at the Joint School for Nanoscience and Nanoengineering. The goals are to 1) matriculate and then graduate STAMPS scholars into STEM careers or graduate school; 2) identify and support a diverse community of STEM learners; 3) create a supportive and self-sustaining environment for STAMPS scholars; and 4) discover what works and why and share this knowledge to a broad audience.