Holding time has limited impact on constitutive innate immune function in a long-lived Antarctic seabird, the Adélie penguin: implications for field studies

Abstract

There is great interest in measuring immune function in wild animals. Yet, field conditions often have methodological challenges related to handling stress, which can alter physiology. Despite general consensus that immune function is influenced by handling stress, previous studies have provided equivocal results. Furthermore, few studies have focused on long-lived species, which may have different stress-immune trade-offs compared to short-lived species that have primarily been tested. Here, we investigate whether capture and handling duration impacts innate immune function in a long-lived seabird, the Adélie penguin (Pygoscelis adeliae). We found no evidence for changes in three commonly used parameters of innate immune function upon holding time of up to 2 h, suggesting that immune function in this species is more robust against handling than in other species. This opens up exciting possibilities for measuring immune function in species with similar life-histories even if samples cannot be taken directly after capture.

Keywords: Antarctic; Ecoimmunology; Field study; Stress.

Fig. 1.

Relationship between hold duration and time point with respect to three immune function markers, agglutination titer, lysis titer and haptoglobin concentration, in Adélie penguins. Data points represent individuals and intensity of data points indicate overlapping datapoints. (N =58, females represented by yellow circles n=24, males represented by blue triangles n=34) Neither hold duration or blood sample time point were included in the best supported models of any of the immune markers.