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

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 Adelie 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.

Automated summary

There is a significant interest in measuring immune function in wild animals, but field conditions often present methodological challenges due to handling stress that can affect physiology. Although it is widely agreed that immune function is influenced by handling stress, previous studies have yielded inconsistent results, particularly in long-lived species. This study investigates the impact of capture and handling duration on innate immune function in the long-lived Adelie penguin and finds no evidence of changes in immune function up to a holding time of 2 hours, suggesting greater resilience against handling stress compared to other species. This opens up possibilities for studying immune function in similar species even if samples cannot be taken immediately after capture.