Sexually dimorphic swallows have higher extinction risk.

Area of Science:

• Evolutionary biology
• Ornithology
• Conservation science

Background:

• The relationship between sexual selection and extinction risk is not fully understood.
• Sexual selection can influence extinction probability, but effects may vary based on ecological factors.
• Analyzing distinct ecological groups may reveal clearer patterns than broad taxonomic comparisons.

Purpose of the Study:

• To investigate the link between sexual plumage dimorphism and extinction risk in swallows (Hirundininae).
• To determine if plumage dimorphism, specifically tail ornamentation, correlates with higher extinction probability in this avian subfamily.

Main Methods:

• Phylogenetic comparative analysis was employed to study 72 species of Hirundininae.
• Sexual plumage dimorphism and tail ornamentation were assessed in relation to perceived extinction risk.
• Species were categorized based on plumage dimorphism (dimorphic vs. monomorphic) and tail length dimorphism.

Main Results:

• Species exhibiting sexually dimorphic plumage faced a higher extinction risk compared to monomorphic species.
• A significant correlation was found between tail length dimorphism and increased extinction risk.
• Five of the 72 studied species are currently considered threatened with extinction.

Conclusions:

• In Hirundininae, sexual selection and resulting plumage dimorphism appear to elevate extinction risk.
• Environmental factors, such as severe weather, may exacerbate the impact of sexual dimorphism on survival in this group.
• The study highlights the complex interplay between sexual selection, morphology, and conservation status in birds.