The control, function, and evolution of sleep in animals has received little attention compared to many other fitness-relevant animal behaviors. Though natural selection has largely been thought of as the driving evolutionary force shaping sleep biology, sexual and social selection may also have transformative effects on sleep quantity and quality in animals. An overarching hypothesis is that increased levels of investment into inter-sexual choice and intra-sexual competition will reduce sleep. An alternative hypothesis is that sexual ornamentation (e.g. avian plumage coloration and song) may have evolved to communicate sleep health and may therefore be positively related to sleep investment. In this dissertation, I studied how sleep is related to components of sexual and social selection in animals (mostly in birds). I first reviewed the literature for empirical examples of how social and sexual selection drive animal sleep patterns and found support for this relationship in some common types of inter-individual interactions (e.g. mating, intra-sexual competition, parent-offspring interactions, group interactions); I also provided new ideas and hypotheses for future research. I then tested associations between sleep behavior with expression of ornaments (song and plumage coloration), using the house finch (Haemorhous mexicanus) as a model system. For both color and song, I found support for the hypothesis that individuals with exaggerated ornaments slept deeper and longer, suggesting that sleep is a critical resource for ornament elaboration and/or may be communicated by both types of sexual signal. Following this, I tested the phylogenetic association between sleep and social/sexual selection as well as other life-history traits across birds. I found that more territorial bird species sleep less, that polygynous birds sleep more than monogamous and polygynandrous birds, and that birds migrating longer distances sleep less and have less REM sleep. Finally, in the interest of applying basic knowledge about sleep biology to current global problems, I found support for the hypothesis that house finches from city environments have developed resilience to artificial light pollution at night. Altogether, I found that social, sexual, and life-history traits are indeed important and overlooked drivers of sleep behavior from multiple levels of analysis.

Humans have greatly altered the night-time photic environment via the production of artificial light at night (ALAN; e.g. street lights, car traffic, billboards, lit buildings). ALAN is problematic because it may significantly alter the seasonal/daily physiological rhythms or behaviors of animals. There has been considerable interest in the impacts of ALAN on health in humans and lab animals, but most such work has centered on adults and we know comparatively little about effects on young animals. We exposed 3-week-old king quail (Excalfactoria chinensis) to a constant overnight blue-light regime for 6 weeks and assessed weekly bactericidal activity of plasma against Escherichia coli - a commonly employed metric of innate immunity in animals. We found that chronic ALAN exposure significantly increased immune function, and that this elevation in immune performance manifested at different developmental time points in males and females. These results counter the pervasive notion that overnight light exposure is universally physiologically harmful to diurnal organisms and indicate that ALAN can provide sex-specific, short-term immunological boosts to developing animals.

Historically, studies of condition-dependent signals in animals have been male-centric, but recent work suggests that female ornaments can also communicate individual quality (e.g., disease state, fecundity). There has been a surge of interest in how urbanization alters signaling traits, but we know little about if and how cities affect signal expression in female animals. We measured carotenoid-based plumage coloration and coccidian (Isospora spp) parasite burden in desert and city populations of house finches to examine urban impacts on male and female health and attractiveness. In earlier work, we showed that male house finches are less colorful and more parasitized in the city, and we again detected that pattern in this study for males. However, though city females are also less colorful than their rural counterparts, we found that rural females were more parasitized. Also, regardless of sex and unlike rural birds, more colorful birds in the city were more heavily infected with coccidia. These results show that urban environments can disrupt signal honesty in female animals and highlight the need for more studies on how cities affect disease and condition-dependent traits in both male and female animals.

There are two electrophysiological states of sleep in birds (rapid-eye-movement sleep [REM] and slow-wave sleep [SWS]), which have different functions and costs. REM improves memory consolidation, while SWS is neuro-restorative but also exposes the animal to more risk during this deep-sleep phase. Birds who sleep in more exposed microsites are known to invest proportionally less in SWS (presumably to ensure proper vigilance), but otherwise little else is known about the ecological or behavioral predictors of how much time birds devote to REM v. SWS sleep. In this comparative analysis, we examine how proportional time spent in SWS v. REM is related to brain mass and duration of the incubation period in adults. Brain mass and incubation period were chosen as predictors of sleep state investment because brain mass is positively correlated with body size (and may show a relationship between physical development and sleep) and incubation period can be a link used to show similarities and differences between birds and mammals (using mammalian gestation period). We hypothesized that (1) species with larger brains (relative to body size and also while controlling for phylogeny) would have higher demands for information processing, and possibly proportionally outweigh neuro-repair, and thus devote more time to REM and that (2) species with longer incubation periods would have proportionally more REM due to the extended time required for overnight predator vigilance (and not falling into deep sleep) while on the nest. We found, using neurophysiological data from literature on 27 bird species, that adults from species with longer incubation periods spent proportionally more time in REM sleep, but that relative brain size was not significantly associated with relative time spent in REM or SWS. We therefore provide evidence that mammalian and avian REM in response to incubation/gestation period have convergently evolved. Our results suggest that overnight environmental conditions (e.g. sleep site exposure) might have a greater effect on sleep parameters than gross morphological attributes.

This study is an exploration of the nutritional physiology of Gambel's quail, Callipepla gambelii, in terms of the comparison of rural and urban area populations of this gallinaceous species, and the employment of in situ study by design. The health of quail populations is of interest as a resource to recreational enthusiasts, hunters, stakeholders, as well as agencies charged with their management. Quail are the only resident small avian game species known to be native to the southwest that is depended upon by management agencies for recreational opportunities. The condition of the Gambel's quail populations determine regulatory actions with respect to recreational quailing opportunities and these quail represent a species which shows adjustment to human expansion. The combination of morphologic, physical, and plasma nutrient data gathered from samples during this study are hypothesized to show a difference between rural and urban populations of C. gambelii. The hypothesis is that urban quail will display morphological differences, and nutrient differences that are crucial to quail fitness, therefore, potential selective differences. Ground and ambient air temperatures are hypothesized to be higher in urban areas andthus these measurements were taken for site comparison. Plasma nutrient concentrations between rural and urban populations of adult male Gambel's quail were compared for potential existing variations in nutrition. The blood nutrient assays are expected to display increased plasma concentrations of constituents such as glucose, lipids, and proteins, which are known to be involved in growth, reproductive success, and general fitness in the urban quail populations. Morphological data was collected to examine the potential differences in the physical attributes of the sampled quail. A fitness advantage in male Gambel's quail living within urban areas is hypothesized to be associated with differences in plasma nutrients and morphology. The potentially differing plasma nutrients in samples of the C. gambelii in urban versus rural environments is believed to be affected by, and to indicate, differing nutrient availability. Body mass and length, chest circumference as well as skin temperatures were measured to assess potential differences in these outward physical attributes. The urban quail are hypothesized to have reproductive and/or natural selective advantages where their measured morphology may show physical size differences. Differences in the physical attributes of the male Gambel's quail that live in urban areas may be supported through measured morphologic attributes.