Mechanisms of enhancing genetic fitness in Non-Kinship-Based Groups: Insights from Black-necked Cranes

Abstract

Understanding a species’ mating strategies is essential for elucidating their social structures and comprehending the trade-offs involved in optimizing fitness. Our study focuses on the Black-necked Crane (Grus nigricollis), an elusive species native to the Qinghai-Tibetan Plateau, which has remained largely mysterious in terms of its mating strategies and group dynamics. Using 13 microsatellite loci, we have conducted precise sex determination and individual identification, which has been instrumental in constructing detailed breeding pedigrees and calculating intricate kinship coefficients. Our comprehensive DNA analysis, combined with meticulous nest-site mapping, reveals that Black-necked Cranes form non-kinship-based groups and exhibit a strong inclination toward nest-site fidelity, especially among males (Male:100%, Female:71%). Significantly, this research documents, for the first time, a notable tendency for extra-pair copulation in this species (16.6%) and reveals that no pair maintained monogamy throughout the four-year study period. These findings challenge conventional views of crane monogamy and deepen our understanding of avian mating systems, suggesting a strategic adaptation to enhance genetic diversity and prevent inbreeding within the population. This research not only unveils new insights into the complex social structures of these cryptic avian populations but also underscores the urgent need for habitat conservation to ensure the species’ continued survival and adaptability.

Keywords

• Mating Strategies
• Extra-pair Fertilization
• Nest-site Fidelity
• Reproductive Dynamics