Pablo Oyarzun Andrade^1,2 | Claudio Henriquez³ | Juan G. Navedo⁴ | Josefina Gutiérrez^1,2 | Consuelo Martorell¹ | John Quiroga³ | Jonathan Vergara^1,2 | Claudio Verdugo¹

1. Ecology and Evolution of Infectious Diseases Lab, Instituto de Patología Animal, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile. 2. Programa de Doctorado en Ciencias Mención Ecología y Evolución, Escuela de Graduados, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile. 3. Instituto Farmacología y Morfofisiología, Facultad de Ciencias Veterinarias, Universidad Austral de Chile, Valdivia, Chile. 4. Bird Ecology Lab, Instituto de Ciencias Marinas y Limnológicas, Facultad de Ciencias, Universidad Austral de Chile, Valdivia, Chile.

Ponente: Pablo Oyarzun Andrade, p.oyarzun.andrade@gmail.com

Migration consists of long seasonal journeys that entail a high demand for resources for migratory species. This can make distant sites interact through these travellers, transporting biomass, seeds and pathogens, which is why they have traditionally been judged as “superspreaders” of diseases. Throughout the annual cycle, physiological demands change according to the ecological context, and organisms must allocate limited resources to each system to maximize their fitness. Among them, the immune function is one of the most beneficial for the survival of the organism, but also one of the most expensive, either its activation or its maintenance. Therefore, determining the immunological profile will help us understand how these organisms distribute their physiological resources prior to migration and deal with possible infections. In this study, the immunological profile of the migratory shorebird Limosa haemastica is evaluated under natural conditions during its non-reproductive period divided into 3 stages (arrival, fattening, departure). Through 170 plasma samples, components of the immune system (Antibodies, Haptoglobin and BKA) were measured. Preliminary results of the BKA have shown that both arrival and fattening show similar levels of reduction in bacterial growth. This is consistent with studies conducted in other migratory shorebirds, where it is evident that high-quality stopovers rapidly and significantly increase the levels of components of the innate immune system. However, the most striking thing is the decrease in this bactericidal capacity in the phase prior to the flight back to its reproductive area. This can be explained by the reallocation of energy towards activities directly related to long-distance flight and the null encounter with pathogens while they are in this phase. Experiments are still needed to obtain a more complete immunological profile that sheds light on how these birds are immunologically prepared to fly nonstop from pole to pole. Fondecyt N° 1191769. ANID scholarships N° 21212004, 21201700, 21180753.