Meeting Abstract

76.1  Wednesday, Jan. 6  Immune function across latitudinal and urban gradients in a differential migrant O’NEAL, DM*; SWANGER, L; JAWOR, J; FRENCH, SS; KETTERSON, ED; Indiana University; Indiana University; University of Southern Mississippi; Utah State University; Indiana University daoneal@indiana.edu

Recent changes in climate have had significant effects on the behavior, physiology and demography of many migratory species. In the dark-eyed junco (Junco hyemalis), for example, milder winter climate has resulted in significant changes in winter distribution from north to south in the winter range. Females are apparently making shorter migrations than previously, and, at the level of populations, sexual segregation is less well developed in winter. Less is known about whether urbanization has affected habitat selection by sex, either within or between latitudes, and whether changing climate or degree of urbanization have affected winter physiology. In this study, we evaluated the effect of winter habitat on fat stores and immune function (complement activity, bacteria killing ability, and total IgG) in juncos across a latitudinal and urban gradient. We predicted more robust immune responses in birds wintering at more southern latitudes and in rural environments because these areas are thought to have higher prevalence of disease and possibly disease transfer. Results show latitudinal differences in immune function and fat stores, with lower levels of total IgG but higher complement activity and greater fat stores in northern birds. However, there were no significant differences in immune function across the urban gradient despite birds in urban habitats having greater fat stores. These results indicate possible tradeoffs among immune components and potential latitudinal differences in the nature of infection. Additionally, results suggest that winter urban environments may not have detrimental effects on condition contrary to previous studies of urban populations.