Assessment of trophic segregation amongst gentoo penguin ( Pygoscelis papua) individuals in Antarctica using a non-invasive methodology

• Published in: Antarctic Science
• Main Authors: Rabinovich-Larrechea, Lucía, Naya, Daniel E., Cosse, Mariana, Bou, Nadia, Franco-Trecu, Valentina
• Format: Article in Journal/Newspaper
• Language: English
• Published: Cambridge University Press (CUP) 2024
• Subjects: Ardley; Ardley Island; South Shetland Islands; Antarc*; Antarctic Science; Antarctica; Gentoo penguin; Pygoscelis papua
• Online Access: http://dx.doi.org/10.1017/s0954102024000026; https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0954102024000026

Abstract Individual trophic specialization (ITS) refers to the trophic diversification amongst individuals within a population. The gentoo penguin ( Pygoscelis papua ) is considered a trophic generalist at the population level, but little is known about its individual trophic differentiation. We assessed the degree of ITS at one of its main breeding colonies: Ardley Island, South Shetland Islands. We used skin from 19 dead individuals to determine species and sex by molecular methods and a nail for stable isotope analysis of δ 15 N and δ 13 C. Isotopic niche metrics and ITS were estimated for the population and for each sex. We found a moderately high degree of ITS associated with the trophic position of the resources consumed (δ 15 N) for the population and both sexes, as well as a moderate degree of ITS in the foraging habitat (δ 13 C) for the population and females. Females showed a higher exclusive niche area, suggesting that they use resources and foraging areas that males do not, probably related to reproductive energy demands. Given the high population density of this species, ITS could function as a mechanism to decrease intraspecific competition. This combination of genetic and isotopic tools allowed us to provide relevant information on the trophic ecology of the gentoo penguin without manipulating animals or using invasive methods.