Meeting Abstract
How birds contribute to the global spread of disease depends inherently on the physiological and behavioral responses of the host to pathogenic invasion. This is particularly critical during migration when birds traverse large geographic barriers and interact with con/hetero-specifics. Observational studies of how pathogens affect migrating birds are limited in that captures of migrants at stopover provide a single snapshot of the subject in time. These can rarely distinguish the costs of infection from the costs of mounting an immune response, nor can they ascertain the effects of pathogen exposure without subsequent infection. Understanding host-specific responses to antigen exposure is important in modeling super-individual scales of host-pathogen dynamics. We experimentally challenged song sparrows (n=28; Melospiza melodia) and white-throated sparrows (n=27; Zonotrichia albicollis) in autumn migratory condition with non-infectious antigens, then monitored body composition and nocturnal migratory restlessness. Whole body mass of both species increased the day after birds were challenged with lipopolysaccharide (LPS) or keyhole-limpet hemocyanin (KLH), substances that induce an acute-phase immune response. Migratory activity of all sparrows, including sham controls, was reduced the night after receiving treatments. White-throated sparrows, but not song sparrows, challenged with LPS had increased lean mass one week after exposure and KLH-challenged white-throated sparrows exhibited reductions in migratory activity during the week of recovery. Our results suggest that short-term activation of the acute immune response may have effects on migratory condition and activity, specific to certain combinations of hosts and antigens.
