Mealworms (Tenebrio molitor), the larval stage of yellow mealworm beetles, are a popular feeder insect for birds, amphibians, reptiles, fish, and even human populations throughout the world. As such, the goal of this work was to understand how the diet of mealworms impacts their nutritional quality as variations in quality can impact the animals (and humans) that consume them. In this study, 500 mealworms were divided among each of the following substrates designed to model food sources available in urban versus rural, more natural areas: 100% wheat germ (control); 100% Styrofoam; mixture of soil, grasses, and leaves from urban lawns; a mixture of soil, grasses and leaves from rural lawns; 50% mixture of wheat germ + carrots; natural fertilizer; or fertilizer with weed killer. The mealworms were maintained at room temperature and the diets were replaced bi-weekly to prevent spoilage and to remove mealworm waste. Once a week for three weeks, mealworms were sampled from each substrate and frozen at -20°C. After 3 weeks, mealworms housed in wheat germ + carrots weighed significantly more than all other groups (p<0.05), whereas those housed in Styrofoam or urban lawn substrates weighed significantly less at week 3 as compared to week 1 (p<0.01). The urban lawn substrate resulted in greater molting and contained the highest number of pupae, but also the greatest mortality among the substrates. The Bradford method measured the total protein content of mealworms homogenized in phosphate-buffered saline. Mealworms maintained on wheat germ had significantly greater total protein content as compared to mealworms transitioned to any other diet (p<0.05). So, compared to wheat germ, urban foods generally reduced protein, total sugars, and crude fat, although they also decreased oxidized lipoproteins. Urban lawn had lower oxidized lipoprotein content than wheat germ, but levels were higher compared to wheat germ with carrots and natural fertilizer. In addition, urban foods generally increase the water content in mealworms. Urban foods were not much different from rural lawns as no there was difference between urban and rural lawns. Differences in body mass and total protein support the hypothesis that mealworms' nutritional quality is altered by ingesting urban substrates. These data suggest that mealworms (and potentially other insects) in cities may be exposed to food substrates that result in less nutritional value than those living in more natural areas as mimicked by the rural lawn substrates and wheat germ control, although they may be higher in water content.

Understanding the drivers of diet selection by carnivores is key for wildlife conservation and management, particularly in the Anthropocene. Yet, most assessments of predation do not consider how spatio-temporal prey availability or nutrition influence carnivore diet selection. Using a novel data integration approach for camera trap and scat data, I assessed how spatial and temporal components of prey availability influenced diet selection by bobcats (Lynx rufus) in Colorado, USA (Chapter 1) and coyotes (Canis latrans) in Arizona, USA (Chapter 2) in areas of low and moderate levels of urbanization. I also assessed coyote diets using the nutritional geometric framework to determine coyote macronutrient consumption seasonally and relative to urbanization (Chapter 3). My results suggest that cottontail rabbit availability largely drove bobcat predation, and that bobcats consumed prey relative to its availability overall and in wildland areas, but that this relationship weakened in anthropogenic regions. I also found that, overall, models of prey availability that incorporated the temporal overlap between predator and prey taxa predicted bobcat diet selection better than models assessing the spatial availability of prey. Similarly, I found coyotes consumed prey relative to its availability overall and in sites with lower levels of human influence across seasons, but not in moderately urbanized sites. I also found that models of prey availability that incorporated time better predicted coyote diets compared to models assessing the spatial availability of prey. Finally, I observed that the macronutrient composition of coyote diets was similar between moderately and less urbanized sites, particularly in the spring-summer season. However, coyote macronutrient consumption differed seasonally, with coyotes eating more non-protein energy relative to protein energy when carbohydrate-rich mesquite (Prosopis spp.) was more available in the fall-winter. In addition, the consistently high consumption of lipid-rich domestic cats in moderately urbanized sites further supports the hypothesis that coyotes increased their consumption of non-protein energy when available and when assuming protein needs were already met. This dissertation provides new insights into how urbanized landscapes impact carnivore ecology. Since diet selection drives many human-carnivore conflicts, this research can also be used to help inform wildlife management and decision-making in anthropogenic areas.

Birds have the highest blood glucose concentrations of all vertebrates. Meanwhile, birds do not develop the same physiological complications (e.g., increased oxidative stress and glycation) that mammals do when blood glucose is elevated (i.e., diabetes). Therefore, birds may serve as a negative model animal for hyperglycemic complications. The physiological reason for high blood glucose in birds remains largely unknown although several unique characteristics of birds may contribute including a lack of the insulin responsive glucose transport protein, relatively high glucagon concentrations, as well as reliance on fatty acids to sustain the high energetic demands of flight. In breaking down triglycerides for energy, glycerol is liberated, which can be converted to glucose through a process called gluconeogenesis. In addition, the extent to which birds maintain homeostatic control over blood glucose in response to extreme dietary interventions remains unclear and few dietary studies have been conducted in wild-caught birds. Using Mourning Doves (Zenaida macroura) as a model organism, this dissertation tests four hypotheses: 1) Gluconeogenesis contributes to high circulating blood glucose concentration; 2-4) similar to mammals, a fully refined carbohydrate (i.e., white bread diet); a high saturated fat diet (60% kcal from fat); and an urban-type diet comprised of a 1:1 ratio of French fries and birds seed will increase blood glucose compared to a nutritionally-balanced diet after a four-week duration. Contrary to the hypothesis, 150 mg/kg Metformin (which inhibits glycerol gluconeogenesis) increased blood glucose, but 300 mg/kg resulted in no change. However, when 2.5 mg/kg of 1,4-dideoxy-1,4-imino-D-arabinitol (DAB; a glycogenolysis inhibitor) was given with 150 mg/kg of Metformin, blood glucose was not different from the control (50 ul water). This suggests that glycerol gluconeogenesis does not contribute to the naturally high blood glucose in birds and that a low dose of Metformin may increase the rate of glycogenolysis. In addition, all three experimental diets failed to alter blood glucose compared to control diets. Collectively, these results suggest that, in addition to a negative model for diabetes complications, birds can also serve a negative model for diet-induced hyperglycemia. Future research should further examine dietary manipulation in birds while controlling for and examining different variables (e.g., species, sex, duration, diet composition, urbanization).

Organisms regularly face the challenge of having to accumulate and allocate limited resources toward life-history traits. However, direct quantification of how resources are accumulated and allocated is rare. Carotenoids are among the best systems for investigating resource allocation, because they are diet-derived and multi-functional. Birds have been studied extensively with regard to carotenoid allocation towards life-history traits, but direct quantification of variation in carotenoid distribution on a whole-organism scale has yet to be done. Additionally, while we know that scavenger receptor B1 (SCARB1) is important for carotenoid absorption in birds, little is known about the factors that predict how SCARB1 is expressed in wild populations. For my dissertation, I first reviewed challenges associated with statistically analyzing tissue distributions of nutrients (nutrient profiles) and tested how tissue carotenoid distributions (carotenoid profiles) varied by sex, season, health state, and coloration in two bird species, house finches (Haemorhous mexicanus) and zebra finches (Taeniopygia guttata). Then, I investigated the relationship between dietary carotenoid availability, relative expression of SCARB1, and extent of carotenoid-based coloration in a comparative study of wood-warblers (Parulidae). In my review of studies analyzing nutrient profiles, I found that multivariate analyses were the most common, but studies rarely reported intercorrelations among nutrient types. In house finches, all tissue carotenoid profiles varied by sex, season, and coloration. For example, males during autumn (molt) had higher concentrations of 3-hydroxyechinenone (the major red carotenoid in sexually attractive male feathers) in most but not all tissues compared to other season and sex combinations. However, the relationship between color and carotenoid profiles depended on the color metric. In zebra finches, only muscle and spleen carotenoid profiles varied between immune-challenged and control birds. In wood-warblers, I found that capacity to absorb carotenoids was positively correlated with the evolution of carotenoid-based coloration but negatively associated with liver carotenoid accumulation. Altogether, my dissertation illustrates (a) the context-dependence of tissue carotenoid profile variation, (b) that carotenoid-based integumentary coloration is a reflection of tissue carotenoid profiles, and (c) that digestive physiology (e.g., carotenoid absorption) is an important consideration in the study of diet and coloration in wild birds.

Desert ecosystems of the southwest United States are characterized by hot and arid climates, but hibernating bats can be found at high altitudes. The emerging fungal infection, white-nose syndrome, causes mortality in hibernating bat populations across eastern North America and the pathogen is increasingly observed in western regions. However, little is known about the ecology of hibernating bats in the southwest, which can help predict how these populations may respond to the fungus. My study investigated hibernating bats during two winters (2018-2019/2019-2020) at three caves in northern Arizona to: (1) describe diversity and abundance of hibernating bats using visual internal surveys and photographic documentation, (2) determine the duration of hibernation by recording bat echolocation call sequences outside caves and recording bat activity in caves using visual inspection, and (3) describe environmental conditions where hibernating bats are roosting. Adjacent to bats, I collected temperature and relative humidity, which I converted into absolute humidity. I documented hibernation status (i.e. active vs. not active) and roosting body position (i.e. open, partially hidden, and hidden). Between September 2018 and April 2019, 246 bat observations were recorded across the three caves. The majority of bats were identified as Myotis spp. (45.9\%, n=113), followed by Corynorhinus townsendii (45.5\%, n=112), Parastrellus hesperus (4.8\%, n=12), Eptesicus fuscus (3.6\%, n=9). Between September 2019 and April 2020, I documented a total of 361 bat observations across the three caves. C. townsendii was most prevalent (52.9\%, n=191), followed by the category P. hesperus/Myotis spp. (25.7\%, n=93), Myotis spp. (12.4\%, n=45), P. Hesperus (4.4\%, n=16), E. fuscus (3.6\%, n=13) and Unknown (0.8\%, n=3). Average conditions adjacent to bats were, temperature=12.5ºC, relative humidity=53\%, and absolute humidity=4.9 g/kg. Hibernating bats were never observed in large clusters and the maximum hibernating population size was 24, suggesting low risk for pathogen transmission among bats. Hibernation lasted approximately 120 days, with minimal activity documented inside and outside caves. Hibernating bats in northern Arizona may be at low risk for white-nose syndrome based on population size, hibernation length, roosting behavior, and absolute humidity, but other variables (e.g. temperature) indicate the potential for white-nose syndrome impacts on these populations.

Prior studies of Mourning Doves have observed no changed in glucose in response to either a high fat “chow” diet or a white bread diet. In the current feeding study, we fed doves an urban diet, high in carbohydrates, fat, and sodium, which is representative of typical American nutrition accessible to the avian population in an urbanized environment. Based on studies of other avian species that examined the effects of an urban diet on physiology, I hypothesized that doves fed an urban diet would have increased plasma glucose and sodium, which would promote an increase in plasma osmolality. This hypothesis was based on preliminary data that found birds fed an urban diet developed impaired vasodilation compared to seed diet control birds. Therefore, differences in plasma glucose, sodium, and osmolality were examined as increases may contribute to the impairment. Adult doves of both sexes were captured on the Arizona State University, Tempe campus. Doves were placed in two dietary groups: an urban diet consisting of a 50/50 ratio of French fries and nutritionally-balanced bird seed (n=7) and a control group of only the seed diet (n=6). Following the four-week diets, birds were euthanized, and cardiac plasma samples were collected from birds to measure glucose, sodium, and osmolality. There were no significant differences between the two study groups in plasma glucose concentration (p=0.445), sodium concentration (p=0.731), or osmolality (p=0.692). Sodium concentrations were signficantly more variable in birds consuming a seed diet than those that were provided the mixed French fry and seed diet (p=0.014). These results suggest that glucose, sodium, and osmolality likely do not contribute to the altered vasodilation of doves fed an urban diet and that such a diet may not be as detrimental to the doves health given their phenotypic flexibility.

Biodiversity is required to guarantee proper ecosystem structure and function. However, increasing anthropogenic threats are causing biodiversity loss around the world at an unprecedented rate, in what has been deemed the sixth mass extinction. To counteract this crisis, conservationists seek to improve the methods used in the design and implementation of protected areas, which help mitigate the impacts of human activities on species. Marine mammals are ecosystem engineers and important indicator species of ocean and human wellbeing. They are also disproportionally less known and more threatened than terrestrial mammals. Therefore, surrogates of biodiversity must be used to maximize their representation in conservation planning. Some of the most effective surrogates of biodiversity known have only been tested in terrestrial systems. Here I test complementarity, rarity, and environmental diversity as potential surrogates of marine mammal representation at the global scale, and compare their performance against species richness, which is the most popular surrogate used to date. I also present the first map of marine mammal complementarity, and assess its relationship with environmental variables to determine if environmental factors could also be used as surrogates. Lastly, I determine the global complementarity-based hotspots of marine mammal biodiversity, and compare their distributions against current marine protected area coverage and exposure to global indices of human threats, to elucidate the effectiveness of current conservation efforts. Results show that complementarity, rarity, and environmental diversity are all efficient surrogates, as they outcompete species richness in maximizing marine mammal species representation when solving the minimum-set coverage problem. Results also show that sea surface temperature, density, and bathymetry are the top environmental variables most associated with complementarity of marine mammals. Finally, gap analyses show that marine mammals are overall poorly protected, yet moderately exposed to hotspots of cumulative human impacts. The wide distribution of marine mammals justify global studies like the ones here presented, to determine the best strategy for their protection. Overall, my findings show that less popular surrogates of biodiversity are more effective for marine mammals and should be considered in their management, and that the expansion of protected areas in their most important habitats should be prioritized.

The prevalence of obesity and obesity-related disorders have increased world-wide. In the last decade, the intestinal microbiome has become a major indicator of metabolic and gastrointestinal health. Previous research has shown that high-fat diet (HFD) consumption can alter the microbial composition of the gut by increasing the abundance of gram-positive bacteria associated with the onset of obesity and type 2 diabetes. Although, the most common form of obesity and metabolic syndrome intervention is exercise and diet, these recommendations may not improve severe cases of obesity. Thus, an important relevance of my project was to investigate whether the intake of an organometallic complex (OMC) would prevent the onset of metabolic and gastrointestinal complications associated with high-fat diet intake. I hypothesized that the consumption of a HFD for 6 weeks would promote the development of metabolic and gastrointestinal disease risk factors. Next, it was hypothesized that OMC treatment would decrease metabolic risk factors by improving insulin sensitivity and decreasing weight gain. Finally, I hypothesized that HFD-intake would increase the abundance of gram-positive bacteria associated with gastrointestinal disease. My preliminary data investigated the effects of a 6-week HFD on the development of hepatic steatosis, intestinal permeability and inflammation in male Sprague Dawley rats. I found that a 6-week HFD increases hepatic triglyceride concentrations, plasma endotoxins and promotes the production of pro-inflammatory cytokines in the cecum wall. I then investigated whether OMC treatment could prevent metabolic risk factors in male Sprague-Dawley rats fed a HFD for 10 weeks and found that OMC can mitigate risk factors such hyperglycemia, liver disease, impaired endothelial function, and inflammation. Lastly, I investigated the effects of a 10-week HFD on the gastrointestinal system and found an increase in liver triglycerides and free glycerol and alterations of the distal gut microbiome. My results support the hypothesis that a HFD can promote metabolic risk factors, alter the gut microbiome and increase systemic inflammation and that OMC treatment may help mitigate some of these effects. Together, these studies are among the first to demonstrate the effects of a soil-derived compound on metabolic complications. Additionally, these conclusions also provide an essential basis for future gastrointestinal and microbiome studies of OMC treatment.

Human-inhabited or -disturbed areas pose many unique challenges for wildlife, including increased human exposure, novel challenges, such as finding food or nesting sites in novel structures, anthropogenic noises, and novel predators. Animals inhabiting these environments must adapt to such changes by learning to exploit new resources and avoid danger. To my knowledge no study has comprehensively assessed behavioral reactions of urban and rural populations to numerous novel environmental stimuli. I tested behavioral responses of urban, suburban, and rural house finches (Haemorhous mexicanus) to novel stimuli (e.g. objects, noises, food), to presentation of a native predator model (Accipiter striatus) and a human, and to two problem-solving challenges (escaping confinement and food-finding). Although I found few population-level differences in behavioral responses to novel objects, environment, and food, I found compelling differences in how finches from different sites responded to novel noise. When played a novel sound (whale call or ship horn), urban and suburban house finches approached their food source more quickly and spent more time on it than rural birds, and urban and suburban birds were more active during the whale-noise presentation. In addition, while there were no differences in response to the native predator, rural birds showed higher levels of stress behaviors when presented with a human. When I replicated this study in juveniles, I found that exposure to humans during development more accurately predicted behavioral differences than capture site. Finally, I found that urban birds were better at solving an escape problem, whereas rural birds were better at solving a food-finding challenge. These results indicate that not all anthropogenic changes affect animal populations equally and that determining the aversive natural-history conditions and challenges of taxa may help urban ecologists better understand the direction and degree to which animals respond to human-induced rapid environmental alterations.

Reproduction is energetically costly and seasonal breeding has evolved to capitalize on predictable increases in food availability. The synchronization of breeding with periods of peak food availability is especially important for small birds, most of which do not store an extensive amount of energy. The annual change in photoperiod is the primary environmental cue regulating reproductive development, but must be integrated with supplementary cues relating to local energetic conditions. Photoperiodic regulation of the reproductive neuroendocrine system is well described in seasonally breeding birds, but the mechanisms that these animals use to integrate supplementary cues remain unclear. I hypothesized that (a) environmental cues that negatively affect energy balance inhibit reproductive development by acting at multiple levels along the reproductive endocrine axis including the hypothalamus (b) that the availability of metabolic fuels conveys alterations in energy balance to the reproductive system. I investigated these hypotheses in male house finches, Haemorhous mexicanus, caught in the wild and brought into captivity. I first experimentally reduced body condition through food restriction and found that gonadal development and function are inhibited and these changes are associated with changes in hypothalamic gonadotropin-releasing hormone (GnRH). I then investigated this neuroendocrine integration and found that finches maintain reproductive flexibility through modifying the release of accumulated GnRH stores in response to energetic conditions. Lastly, I investigated the role of metabolic fuels in coordinating reproductive responses under two different models of negative energy balance, decreased energy intake (food restriction) and increased energy expenditure (high temperatures). Exposure to high temperatures lowered body condition and reduced food intake. Reproductive development was inhibited under both energy challenges, and occurred with decreased gonadal gene expression of enzymes involved in steroid synthesis. Minor changes in fuel utilization occurred under food restriction but not high temperatures. My results support the hypothesis that negative energy balance inhibits reproductive development through multilevel effects on the hypothalamus and gonads. These studies are among the first to demonstrate a negative effect of high temperatures on reproductive development in a wild bird. Overall, the above findings provide important foundations for investigations into adaptive responses of breeding in energetically variable environments.