Geographic variation in sexual selection and implications for speciation in the Barn Swallow

Elizabeth Sc Scordato,Rebecca J Safran

doi:10.1186/s40657-014-0008-4

Elizabeth Sc Scordato, Rebecca J Safran

Open Access

https://doi.org/10.1186/s40657-014-0008-4

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Journal: Avian Research	Publication Date: Dec 1, 2014
Citations: 111	License type: CC BY 4.0

Affiliation: University of Colorado Boulder

Abstract

Barn Swallows (Hirundo rustica), a group of passerine birds comprised of six closely related subspecies, are well known throughout their nearly worldwide distribution, in part because of their close association with human settlements. A tractable species for both individual-based and population-level studies, Barn Swallows are a prominent model system in evolutionary, ecological, and behavioral research. Here we review work on sexual selection and population divergence in this species complex, focusing on comparative studies among populations and subspecies. We summarize variation in the targets of mate choice and in the information conveyed by sexually selected traits, and conclude that the benefits advertised by different traits may vary geographically. Finally, we consider the role of sexual selection as a driver of population divergence in this widespread and phenotypically variable species complex.

Highlights

A spring and summer inhabitant of the Holarctic, the Barn Swallow (Hirundo rustica) is the most widespread species of the swallow family, Hirundinidae
We summarize data related to sexual selection on these traits in the different subspecies, and consider the role of geographic variation in sexual selection pressures in population divergence and speciation
Plumage coloration in other populations Darker ventral color is associated with greater breeding success in Middle Eastern swallows (H. r. transitiva), a subspecies that exhibits elongated tail streamers and dark ventral color. Experimental work in this subspecies has shown that both ventral color and tail streamer length predict different aspects of breeding success, with darker males raising more young over the course of a season, and males with longer tail streamers breeding earlier and having fewer extra-pair chicks in their nests (Vortman et al 2011, 2013)

Summary

Introduction

A spring and summer inhabitant of the Holarctic, the Barn Swallow (Hirundo rustica) is the most widespread species of the swallow family, Hirundinidae. The North American populations are on average much darker in ventral color, with tail streamers tending to be intermediate in length to other subspecies (Safran et al in review).

Results

Conclusion