Extra-pair fertilizations are more strongly associated with female traits than male traits or fecundity in; Hirundo rustica erythrogaster; (North American Barn Swallow) Journal Article uri icon

Overview

abstract

  • Abstract; Many socially monogamous bird species engage in multiple mating through extra-pair (EP) fertilizations, yet the role of female plumage in EP outcomes is under studied. Sexual selection involving EP fertilization is hypothesized to influence female trait evolution if heritable plumage variation informs EP mating decisions and EP mating decisions affect fitness. Here, we test for 2 key prerequisite patterns of sexual selection through EP fertilizations by asking: (1) is female reproductive success associated with EP fertilizations, and (2) are EP fertilizations associated with female plumage traits? Studying these 2 patterns is essential for better understanding how the costs and benefits of EP fertilizations should translate to sexual selection on female plumage. We provide a conceptual diagram to highlight how plumage traits of both members of a social pair can influence fertilizations within and outside their pair bond from the perspective of each sex. In our sample of 47 Hirundo rustica erythrogaster (North American Barn Swallow) social pairs, females who engaged in EP mating tended to fledge more offspring, and females with longer tails were more likely to mate with EP sires. Furthermore, female traits were more strongly associated with EP fertilizations than male traits for predicting both female and male EP outcomes. Finally, we found that female traits were not correlated with fecundity (total eggs laid) and found no association between fecundity and EP fertilizations. Thus, sexual selection on EP fertilizations may be more important than selection on fecundity for understanding female plumage variation in our study population. Taken together, we provide evidence for multiple conditions necessary for sexual selection on female plumage traits in H. r. erythrogaster that are likely also relevant for understanding female trait evolution in other socially monogamous birds.

publication date

  • March 15, 2026

Date in CU Experts

  • April 16, 2026 2:05 AM

Full Author List

  • Kenny-Duddela HV; Schield DR; Laubach ZM; Levin II; Keller KP; Safran RJ

author count

  • 6

Other Profiles

International Standard Serial Number (ISSN)

  • 0004-8038

Electronic International Standard Serial Number (EISSN)

  • 2732-4613

Additional Document Info

number

  • ukag013