Disruptive sexual selection for plumage coloration in a passerine bird

Abstract

The theory of sexual selection was developed to explain the evolution of highly exaggerated sexual ornaments. Now supported by vast empirical evidence, sexual selection is generally considered to favour individuals with the most extreme trait expression. Here we describe disruptive selection on a sexual ornament, plumage coloration, in yearling male lazuli buntings (Passerina amoena). In habitats with limited good-quality nesting cover, the dullest and the brightest yearlings were more successful in obtaining high-quality territories, pairing with females and siring offspring, than yearlings with intermediate plumage. This pattern reflects the way that territorial adult males vary levels of aggression to influence the structure of their social neighbourhood. Adult males showed less aggression towards dull yearlings than intermediate and bright ones, permitting the dull yearlings to settle on good territories nearby. Fitness comparisons based on paternity analyses showed that both the adults and dull yearlings benefited genetically from this arrangement, revealing a rare example of sexually selected male-male cooperation.

Predictors of male insemination success in the mosquitofish (Gambusia holbrooki)

“…These studies have shown that selection due to female mate preferences is often both nonlinear (e.g., Greene et al. 2000; Brooks et al. 2005; Gerhardt and Brooks 2009) and favors specific trait combinations rather than acting independently on each trait (i.e., there is correlational selection) (e.g., Blows et al.…”

The signaling function of plumage characteristics in female tree swallows and implications for reproductive success and life-history decisions.

“…On the other hand, DPM has been found to be beneficial to SY females by reducing aggression from males (Stutchbury and Robertson 1987a) and females (Lozano and Handford 1995; Chapter 2) during the breeding season. Perhaps there are social consequences of displaying more iridescent bluegreen plumage for SY females (Senar et al 1998;Greene et al 2000). If iridescent bluegreen plumage is a signal of breeding experience in female tree swallows, this plumage colouration may elicit more aggression from ASY females and may represent an evolutionary motivation for the maintenance of DPM in SY female tree swallows.…”

“…SY female tree swallows that exhibit higher amounts of DPM may be displaying their age and inexperience more honestly to older individuals and therefore could face less harassment compared to more adult-coloured SY females. SY females with more DPM could 37 therefore have increased reproductive success if they are not targets of aggression from older individuals (Greene et al 2000).…”

“…I also investigate male reproductive investment in relation to SY female plumage colouration and whether pairs mate assortatively by plumage characteristics, which may indicate that males are assessing female quality based on plumage colouration. To my knowledge, DPM has never been examined as an indicator of quality and thus the variation in DPM among individuals has rarely been examined (but see Hill 1988;Grant 1990;Greene et al 2000). By examining the variation within this plumage trait, I am seeking to understand if there are selective forces not normally considered that may have influenced the existence of DPM in this species.…”

Evolution of plumage coloration in the crow family (Corvidae) with a focus on the color-producing microstructures in the feathers: a comparison of eight species

“…Specifically, plumage coloration has been investigated in terms of sexual selection (Darwin 1871;Andersson 1994), geographical differentiation and speciation (Mayr 1963), evolution of sexual dimorphism (Dunn et al 2001) and evolution of polymorphisms (Roulin 2004). Researchers continue using plumage coloration as a model subject for a variety of questions that comprise the center of modern evolutionary biology (Greene et al 2000;Palleroni et al 2005;Rubenstein & Lovette 2009;Clarke et al 2010).…”