Meeting Abstract

76.3  Wednesday, Jan. 6  No seasonal modulation in the acute phase response of a temperate zone bird, the Skylark (Alauda arvensis) HEGEMANN, A*; VERSTEEGH, MA; DE GRAAF, M; TIELEMAN, BI; MATSON, KD; University of Groningen, The Netherlands; University of Groningen, The Netherlands; University of Groningen, The Netherlands; University of Groningen, The Netherlands; University of Groningen, The Netherlands a.hegemann@rug.nl

We studied the interactions between energy balance and different indices of the immune function to shed light on how birds cope with different seasons. If certain seasons are particularly challenging in terms of energy availability, then free-living birds may be forced to compromise some immune functions because they cannot otherwise meet their total energetic requirements. Alternatively, overall immune function might shift towards a mix of components that is energetically less costly. To investigate these possibilities, we studied the energetic costs of an immune response throughout the annual cycle of the Skylark (Alauda arvensis), a widespread and typical temperate zone species. We caught birds in five distinct seasons (spring migration, breeding, moulting, autumn migration and winter), and we experimentally-induced acute phase responses through injection of lipopolysaccharide (LPS). We measured metabolic rate, body temperature, body mass loss, and blood sugar and ketone levels during the acute phase response period and compared LPS-injected birds and un-injected control birds. These comparisons revealed that all measured traits were significantly higher in birds that were undergoing an LPS-induced acute phase response, indicating that the acute phase response is costly. At the same time, and more surprisingly, we found no significant interaction between season and LPS-injection for any of the measured parameters. Thus, the cost of an acute phase response is high throughout the annual cycle, and the costs are not seasonally modulated.