Keywords

Florida scrub jay, plumage color, uv blue, dominance, heritability, suburban, condition, dispersal, signaling

Abstract

Ornamental traits are considered honest advertisements of fitness, and their evolution is usually explained in terms of sexual selection. This explanation remains unsatisfactory in some instances, for example, juvenile birds whose plumage is molted prior to adulthood and breeding. I first evaluate whether juvenile plumage reflectance signals dominance status in the Federally Threatened Florida scrub-jay (Aphelocoma coerulescens) using a combination of observational and experimental methods. Then I estimate the heritability, non-genetic maternal and environmental effects, and strength of selection on juvenile plumage reflectance using archived feather samples and a pedigree constructed from historical nest records. Finally, I compare plumage reflectance and its use as a signal between a wildland and suburban population of scrubjays. I conclude that plumage reflectance is a signal of dominance, and that social selection can also drive the evolution of sexually dimorphic traits. In this species, plumage reflectance is heritable and influenced by maternal effects, but environmental effects are inconsequential. Although this trait appears to have an important function, only mean brightness and female hue are associated with lifetime reproductive success. Plumage reflectance was more UV-shifted in the suburban birds, but there is no reason to believe that urbanization decreases the value of this plumage as a signal. However, these plumage differences may facilitate dispersal from suburban areas, contributing to the decline of suburban populations.

Notes

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Graduation Date

2013

Semester

Fall

Advisor

Noss, Reed

Degree

Doctor of Philosophy (Ph.D.)

College

College of Sciences

Department

Biology

Degree Program

Conservation Biology; Ecology and Organismal Biology

Format

application/pdf

Identifier

CFE0005431

URL

http://purl.fcla.edu/fcla/etd/CFE0005431

Language

English

Release Date

June 2015

Length of Campus-only Access

1 year

Access Status

Doctoral Dissertation (Open Access)

Subjects

Dissertations, Academic -- Sciences, Sciences -- Dissertations, Academic

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