Major activities require the use of large amounts of energy and commitment of individual resources. At the same time animals need to be able to respond to the challenges of possible disease and infection. The research will use the monarch butterfly, which makes two major yearly migrations to determine how energy extensive events like migration impact the ability of the immune system to respond to challenges. Monarch butterflies (Danaus plexippus) are iconic insects that undergo one of the longest distance two-way migrations of any insect species in the world, traveling from as far North as Canada to overwintering sites in Central Mexico each year. Using monarchs as a model, this project will investigate the effects of movement and reproduction on immunity throughout the course of the annual migratory cycle. Because of their long journeys and coverage of diverse habitats, migratory animals have far-reaching implications for the spread of infectious diseases, and can harbor pathogens of known human health risks such as West Nile virus, avian influenza virus and Ebola virus. This project will help provide a framework for determining the points along their annual cycles that migratory species might be most vulnerable to infectious diseases.
This dissertation project has previously established that immune defense in monarchs is resource-limited, trades-off against growth, and is associated with migratory distances in the wild. The study proposed here will experimentally manipulate reproduction and flight to measure their independent consequences for components of monarch immune defense. One experiment will manipulate reproductive diapause (a precursor to migration) to examine whether reproductive maturity alone lowers host defenses, or if animals must actively reproduce to experience these costs. A second experiment will mimic active flight in monarchs and measure resulting changes in immune defense for both reproductive and non-reproductive adults. In combination, these studies will help identify factors that underlie immune variation in this and other migratory species. This interdisciplinary project draws on concepts and methods from animal behavior, physiology, ecology and immunology. The physiological and behavioral mechanisms of migration remain under active study owing in part to recent advances in tracking mobile species over long distances. Using an experimentally tractable species, this work will advance general understanding of how immune defense can change throughout the annual migratory cycle and how this depends on competing demands of movement and reproduction.
Data storage and sharing: Data will be stored on an external storage device as well as a secure server space in the Odum School of Ecology. In addition, UGA libraries maintain an institutional repository for data storage. All main data files will be shared as tab delimited text files at the Dryad Digital Repository (http://datadryad.org/) in conjunction with publication or within 2 years of completing the proposed research. Because the work involves a non-model insect species with implications for researchers studying ecoimmunology and disease ecology, the co-PIs will share pertinent experimental information (i.e. optimized immune assay protocols) with the Research Coordination Network in Ecoimmunology (http://ccoon.myweb.usf.edu/ecoimmunology.org/About_Home.html)
