Regurgitation of the koilin layer in chinstrap penguins (Pygoscelis antarcticus) and its association with gastric parasites

  • Han-Kyu Kim Seoul National University
  • Chang-Yong Choi Seoul National University
  • Min-Su Jeong Seoul National University
  • Hwa-Yeon Kang Seoul National University
  • Woo-Shin Lee Seoul National University
Keywords: uticula gastris, host-parasite interaction, nematodes, parasitic load, regurgitation, Stegophorus macronectes


The koilin membrane, formed by the secretions of the ventricular and pyloric glands, functions as a protective layer in the gizzards of most bird species. However, the ecological functions of koilin have never been studied in free-ranging penguins. During the two austral summers from 2012 to 2014, we observed the regurgitated koilins of chinstrap penguins (Pygoscelis antarcticus) at Narębski Point on King George Island, South Shetland Islands, and we detected a significant difference in the daily accumulation of regurgitated koilins between the pre-hatching and post-hatching periods in the rookery. We also found 233 gastrointestinal parasites, all Stegophorus macronectes (Nematoda, Acuariidae), from 26 out of 45 koilins freshly regurgitated by chinstrap penguins. We suggest that the regurgitation of koilins may benefit adult chinstrap penguins in the wild by reducing parasitic loads when they fast during incubation; it may also help decrease the risk of parasite transmission to chicks. Our results present the first observations of regurgitated koilins among breeding chinstrap penguins. How koilin regurgitation functions in penguins requires further study. Among the gentoo penguins (P. papua) co-occurring at the study site, we observed no regurgitated koilin layers.

Keywords: Cuticula gastris; host-parasite interaction; nematodes; parasitic load; regurgitation; Stegophorus macronectes.

(Published: 21 June 2016)

Citation: Polar Research 2016, 35, 25966,


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Author Biographies

Han-Kyu Kim, Seoul National University
Department of Forest Sciences
Chang-Yong Choi, Seoul National University
Phd, Research professor, College of agriculture and life sciences
Hwa-Yeon Kang, Seoul National University
Department of Forest Sciences
Woo-Shin Lee, Seoul National University
Phd, Professor, Department of Forest Sciences
How to Cite
Kim, H.-K., Choi, C.-Y., Jeong, M.-S., Kang, H.-Y., & Lee, W.-S. (2016). Regurgitation of the koilin layer in chinstrap penguins (<em>Pygoscelis antarcticus</em&gt;) and its association with gastric parasites. Polar Research, 35.
Research Notes