Arianne J. Cease, Ph.D. - US grants

This Doctoral Dissertation Enhancement award will support field research on grasshopper migration in China by Ph.D. student Arianne Cease of Arizona State University. Several specific questions will be addressed in this research including: 1) Do migratory forms of grasshopper result from superior or inferior diet quality? 2) Can transitions between migratory and nonmigratory forms be triggered by changes in specific plant characteristics, such as nitrogen, carbon, phosphorus, or alkaloid content? 3) Does overgrazing stimulate formation of migratory forms by lowering plant nutritional quality? To address these questions, the density and diet of Oedaleus asiaticus will be manipulated in the lab and observed in the field, and morphological, physiological and behavioral responses of developing grasshoppers will be recorded. This award will promote a highly interdisciplinary collaboration by a group of NSF-funded ecologists and insect physiologists with grasshopper biologists and grassland botanists in China. Collaborative activities funded by this award will include research at the Beijing Institute of Life Sciences and the State Key Laboratory of Integrated Management of Insect & Rodent Pests involving multiple Chinese and US scientists. Finally, this research will provide critical data necessary to understand and potentially prevent disastrous locust swarms.

During an outbreak year, swarming grasshoppers (locusts) can populate 11 million square miles of land worldwide, negatively affecting more than 60 countries and the livelihood of 1 out of every 10 people. Global climate change is predicted to increase precipitation variability and perhaps exacerbate locust outbreaks. While it is often hypothesized that dietary cues related to deteriorating environmental conditions might trigger locust swarms, the specific dietary cues that may cause this developmental plasticity are unknown. This research will investigate the question in China, using the grasshopper O. asiaticus, one of two economically important outbreak locusts in Asia. This research will also establish long-term international research ties and promote a globally engaged scientific workforce focused on an important agricultural problem.

Research has recently shown that overgrazing of livestock in a grassland in China lowered the nitrogen content of the grasses and that this caused a rise in the abundance of a locust likely to lead to locust swarms. This proposal will test whether this is also true for related species of locust in Australia and western Africa, and link both grazing practices and locust swarms to economics and social policy in the three contrasting regions. Three biologists and three social scientists will team up to help answer: (1) How do insect-nutrient relations and livestock grazing strategies interact to affect food prices, food security, and rangeland degradation? (2) How do property rights regimes affect the adaptive capacity of societies to respond to the link between overgrazing and locust outbreaks? Because both market forces and locust swarms operate over long distances, these effects are likely to be global.

Locust outbreaks have had devastating effects on food security, impacting crop and livestock yields. This proposal aims to develop new, sustainable strategies to understand and manage locust outbreaks, accounting for feedbacks among ecological, agricultural, and economic systems. Results will be translated directly into management and policy recommendations through collaborations with agricultural agencies. The project will also strengthen international scientific collaboration, train undergraduate and graduate students, and develop a multi-media outreach program for K-12 students and teachers.

In this Award from the NSF Science, Engineering and Education for Sustainability Fellows (SEES Fellows Program), Dr. Arianne Cease from Arizona State University will investigate the interesting dynamic coupling between land use for agriculture (grazing of livestock) and the outbreak of swarms of locusts. This award is supported by the Directorate for Biological Sciences, the Directorate for Social, Behavioral and Economic Sciences and the Office of Integrative and International Activities.

The proposed work will (1) develop a bioeconomic model to investigate the interactions between human behavior, insect-nutrient relations, and food security, via mathematical modeling of this complex system; (2) investigate how rangeland management impacts Oedalus locust outbreaks and migration through changes in macronutrients available in their food plants; and (3) work with stakeholders to devise policy which takes into account livestock-locust interactions and disseminate these findings through aid agencies to populations impacted by locusts.

The aim of studies like that proposed in this work is to develop better land management practices that take into account the unusually complex couplings between agricultural activities and ecological systems.

Dr. Cease will be working with collaborators Prof. Jon Harrison of the School of Life Sciences of Arizona State University as well as Prof. Eli Fenechel at the School of Forestry and Environmental Studies of Yale University. The work will also involve collaboration with Profs. James Elser and Asst. Dean Charles Kazilek at Arizona State University; Prof. Stephen J. Simpson of the School of Biological Sciences, University of Sydney and Dr. James D. Woodman of the Australian Plague Locust Commission; and Dr. Todd Crosby of USAID/Project Yaajeenda and Dr. Aliou Diongue of the Plant Protection Service, Senegal.

This project is supported under the NSF Science, Engineering and Education for Sustainability Fellows (SEES Fellows) program, with the goal of helping to enable discoveries needed to inform actions that lead to environmental, energy and societal sustainability while creating the necessary workforce to address these challenges. With SEES Fellows support, this project will enable a promising early career researcher to establish themselves in an independent research career related to sustainability.