Matching Items (59)
Description
Though it is a widespread adaptation in humans and many other animals, parental care comes in a variety of forms and its subtle physiological costs, benefits, and tradeoffs related to offspring are often unknown. Thus, I studied the hydric, respiratory, thermal, and fitness dynamics of maternal egg-brooding behavior in Children's pythons (Antaresia childreni). I demonstrated that tight coiling detrimentally creates a hypoxic developmental environment that is alleviated by periodic postural adjustments. Alternatively, maternal postural adjustments detrimentally elevate rates of egg water loss relative to tight coiling. Despite ventilating postural adjustments, the developmental environment becomes increasingly hypoxic near the end of incubation, which reduces embryonic metabolism. I further demonstrated that brooding-induced hypoxia detrimentally affects offspring size, performance, locomotion, and behavior. Thus, parental care in A. childreni comes at a cost to offspring due to intra-offspring tradeoffs (i.e., those that reflect competing offspring needs, such as water balance and respiration). Next, I showed that, despite being unable to intrinsically produce body heat, A. childreni adjust egg-brooding behavior in response to shifts in nest temperature, which enhances egg temperature (e.g., reduced tight coiling during nest warming facilitated beneficial heat transfer to eggs). Last, I demonstrated that A. childreni adaptively adjust their egg-brooding behaviors due to an interaction between nest temperature and humidity. Specifically, females' behavioral response to nest warming was eliminated during low nest humidity. In combination with other studies, these results show that female pythons sense environmental temperature and humidity and utilize this information at multiple time points (i.e., during gravidity [egg bearing], at oviposition [egg laying], and during egg brooding) to enhance the developmental environment of their offspring. This research demonstrates that maternal behaviors that are simple and subtle, yet easily quantifiable, can balance several critical developmental variables (i.e., thermoregulation, water balance, and respiration).
ContributorsStahlschmidt, Zachary R (Author) / DeNardo, Dale F (Thesis advisor) / Harrison, Jon (Committee member) / McGraw, Kevin (Committee member) / Rutowski, Ronald (Committee member) / Walsberg, Glenn (Committee member) / Arizona State University (Publisher)
Created2011
Description
Studies of animal contests often focus solely on a single static measurement of fighting ability, such as the size or the strength of the individual. However, recent studies have highlighted the importance of individual variation in the dynamic behaviors used during a fight, such as, assessment strategies, decision making, and fine motor control, as being strong predictors of the outcome of aggression. Here, I combined morphological and behavioral data to discover how these features interact during aggressing interactions in male virile crayfish, Faxonius virilis. I predicted that individual variation in behavioral skill for decision making (i.e., number of strikes thrown), would determine the outcome of contest success in addition to morphological measurements (e.g. body size, relative claw size). To evaluate this prediction, I filmed staged territorial interactions between male F. virilis and later analyzed trial behaviors (e.g. strike, pinches, and bout time) and aggressive outcomes. I found very little support for skill to predict win/loss outcome in trials. Instead, I found that larger crayfish engaged in aggression for longer compared to smaller crayfish, but that larger crayfish did not engage in a greater number of claw strikes or pinches when controlling for encounter duration. Future studies should continue to investigate the role of skill, by using finer-scale techniques such as 3D tracking software, which could track advanced measurements (e.g. speed, angle, and movement efficiency). Such studies would provide a more comprehensive understanding of the relative influence of fighting skill technique on territorial contests.
ContributorsNguyen, Phillip Huy (Author) / Angilletta, Michael (Thesis director) / McGraw, Kevin (Committee member) / School of Life Sciences (Contributor) / Barrett, The Honors College (Contributor)
Created2021-05
Description
Human-induced rapid environmental change (HIREC) influences nearly all of Earth's ecosystems through processes such as urbanization. Previous studies have found that urbanization influences biodiversity patterns, often yielding an increase in the abundance of a few urban-adapted taxa at the expense of native species diversity. The western black widow spider, Latrodectus hesperus, is a medically-important pest species that often forms dense urban subpopulations (i.e., infestations) relative to the low-density subpopulations found throughout undisturbed, desert habitat. Here, I employ field and laboratory studies to examine the population ecology and stoichiometry of this urban pest to increase our understanding of the mechanisms underlying its success. The population ecology of ten black widow subpopulations spread across metropolitan Phoenix, AZ was examined during the peak breeding season (June-August). This study revealed that arthropod prey abundance, female mass and population density of females showed significant spatial variation across the ten subpopulations. Additionally, prey abundance and foraging success, measured as the number of carcasses found in webs, were a strong determinant of female mass and population density within each subpopulation. To test the mechanisms that drive black widow infestations, I used ecological stoichiometry to examine the nutrient (nitrogen and phosphorus) composition of spiders and arthropod prey from urban habitat, desert habitat and a laboratory diet regime. These studies revealed that (1) spiders are more nutrient rich than cricket prey in the field, (2) spider subpopulations exhibit significant spatial variation in their nitrogen composition, (3) nutrient composition of urban spider subpopulations does not differ significantly from Sonoran desert subpopulations, (4) laboratory-reared spiders fed a diet of only laboratory-reared crickets are more nitrogen and phosphorus limited than field-captured spiders, and (5) cannibalism by laboratory-reared spiders alleviated phosphorus limitation, but not nitrogen limitation, when compared to field-captured spiders. This work highlights the need to examine the population ecology of species relationships, such as predator-prey dynamics, to fully understand the fecundity and population growth of urban pest species. Moreover, the integration of population ecology and stoichiometry illustrates the need to address mechanisms like nutrient limitation that may explain why urban pest populations thrive and native species diversity suffers following HIREC.
ContributorsTrubl, Patricia (Author) / Johnson, James C. (Thesis advisor) / Rutowski, Ronald (Thesis advisor) / McGraw, Kevin (Committee member) / Arizona State University (Publisher)
Created2012
Description
This dissertation investigates the condition of skeletal muscle insulin resistance using bioinformatics and computational biology approaches. Drawing from several studies and numerous data sources, I have attempted to uncover molecular mechanisms at multiple levels. From the detailed atomistic simulations of a single protein, to datamining approaches applied at the systems biology level, I provide new targets to explore for the research community. Furthermore I present a new online web resource that unifies various bioinformatics databases to enable discovery of relevant features in 3D protein structures.
ContributorsMielke, Clinton (Author) / Mandarino, Lawrence (Committee member) / LaBaer, Joshua (Committee member) / Magee, D. Mitchell (Committee member) / Dinu, Valentin (Committee member) / Willis, Wayne (Committee member) / Arizona State University (Publisher)
Created2013
Description
While exercising mammalian muscle increasingly relies on carbohydrates for fuel as aerobic exercise intensity rises above the moderate range, flying birds are extraordinary endurance athletes and fuel flight, a moderate-high intensity exercise, almost exclusively with lipid. In addition, Aves have long lifespans compared to weight-matched mammals. As skeletal muscle mitochondria account for the majority of oxygen consumption during aerobic exercise, the primary goal was to investigate differences in isolated muscle mitochondria between these species and to examine to what extent factors intrinsic to mitochondria may account for the behavior observed in the intact tissue and whole organism. First, maximal enzyme activities were assessed in sparrow and rat mitochondria. Citrate synthase and aspartate aminotransferase activity were higher in sparrow compared to rat mitochondria, while glutamate dehydrogenase activity was lower. Sparrow mitochondrial NAD-linked isocitrate dehydrogenase activity was dependent on phosphate, unlike the mammalian enzyme. Next, the rate of oxygen consumption (JO), electron transport chain (ETC) activity, and reactive oxygen species (ROS) production were assessed in intact mitochondria. Maximal rates of fat oxidation were lower than for carbohydrate in rat but not sparrow mitochondria. ETC activity was higher in sparrows, but no differences were found in ROS production between species. Finally, fuel selection and control of respiration at three rates between rest and maximum were assessed. Mitochondrial fuel oxidation and selection mirrored that of the whole body; in rat mitochondria the reliance on carbohydrate increased as the rate of oxygen consumption increased, whereas fat dominated under all conditions in the sparrow. These data indicate fuel selection, at least in part, can be modulated at the level of the mitochondrial matrix when multiple substrates are present at saturating levels. As an increase in matrix oxidation-reduction potential has been linked to a suppression of fat oxidation and high ROS production, the high ETC activity relative to dehydrogenase activity in avian compared to mammalian mitochondria may result in lower matrix oxidation-reduction potential, allowing fatty acid oxidation to proceed while also resulting in low ROS production in vivo.
ContributorsKuzmiak, Sarah (Author) / Willis, Wayne T (Thesis advisor) / Mandarino, Lawrence (Committee member) / Sweazea, Karen (Committee member) / Harrison, Jon (Committee member) / Gadau, Juergen (Committee member) / Arizona State University (Publisher)
Created2012
Description
Parental care provides many benefits to offspring. One widely realized benefit is enhanced regulation of offspring's thermal environment. The developmental thermal environment during development can be optimized behaviorally through nest site selection and brooding, and it can be further enhanced by physiological heat production. In fact, enhancement of the developmental thermal environment has been proposed as the initial driving force for the evolution of endothermy in bird and mammals. I used pythons (Squamata: Pythonidae) to expand existing knowledge of behavioral and physiological parental tactics used to regulate offspring thermal environment. I first demonstrated that brooding behavior in the Children's python (Antaresia childreni) is largely driven by internal mechanisms, similar to solitary birds, suggesting that the early evolution of the parent-offspring association was probably hormonally driven. Two species of python are known to be facultatively thermogenic (i.e., are endothermic during reproduction). I expand current knowledge of thermogenesis in Burmese pythons (Python molurus) by demonstrating that females use their own body temperature to modulate thermogenesis. Although pythons are commonly cited as thermogenic, the actual extent of thermogenesis within the family Pythonidae is unknown. Thus, I assessed the thermogenic capability of five previously unstudied species of python to aid in understanding phylogenetic, morphological, and distributional influences on thermogenesis in pythons. Results suggest that facultative thermogenesis is likely rare among pythons. To understand why it is rare, I used an artificial model to demonstrate that energetic costs to the female likely outweigh thermal benefits to the clutch in species that do not inhabit cooler latitudes or lack large energy reserves. In combination with other studies, these results show that facultative thermogenesis during brooding in pythons likely requires particular ecological and physiological factors for its evolution.
ContributorsBrashears, Jake (Author) / DeNardo, Dale (Thesis advisor) / Harrison, Jon (Committee member) / Deviche, Pierre (Committee member) / McGraw, Kevin (Committee member) / Smith, Andrew (Committee member) / Arizona State University (Publisher)
Created2012
Description
Self-maintenance behaviors, like preening in birds, can have important effects on fitness in many animals. Birds produce preen oil, which is a mixture of volatile and non-volatile compounds, that is spread through their feathers during grooming and influences feather integrity, waterproofing, and coloration. As urban areas grow and present conditions that may demand increased feather self-maintenance (e.g. due to soiling, pollution, elevated UV exposure due to natural habitat alterations), it is important to examine how preening and preen oil may be affected by this process. I assessed variation in preen oil composition in house finches (Haemorhous mexicanus) as a function of sex, urbanization, and plumage hue, a sexually selected indicator of male quality. Preen oil samples from birds captured at urban and rural sites were analyzed using gas chromatography-mass spectrometry. We detected 18 major peaks, which we tentatively identified as esters, and found that, although there were no sex or urban-rural differences in preen oil constituents, there was a significant interactive effect of sex and urbanization, with rural females and urban males having higher amounts of some components. This suggests that factors that vary with sex or urbanization, such as the timing of seasonal cycles, are affecting preen oil composition. There were no significant relationships between coloration and preen oil composition, suggesting that preen oil composition does not vary with male quality.
ContributorsBrooks, Ellen Elizabeth (Author) / McGraw, Kevin (Thesis director) / Liebig, Juergen (Committee member) / Weaver, Melinda (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05
Description
Testosterone (T) is a steroid hormone that affects behavior and reproductive traits (e.g. spermatogenesis and ornamentation) in vertebrates. In addition to long-term influences, T can rapidly increase in males following aggressive male-male encounters. Less is known how females directly influence male T and behavior, though research with humans suggests that sexually attractive females elicit a greater increase in male T and reproductive behavior than unattractive females. In birds, the influence of female attractiveness on male T and behavior is currently untested. We hypothesized that T and courtship behavior in male zebra finches would correlate with female attractiveness. We used red leg bands to make females "attractive" and green bands to make them "unattractive" (unbanded females were controls) as previous research suggests that zebra finches prefer red colors over green in mating contexts. We collected blood from males before and after "speed-dating" trials to measure changes in plasma T and analyzed male courtship behaviors from trial video recordings. The likelihood of plasma T increasing after a trial was significantly greater in males who were with red-banded females compared to control females, suggesting males may find them more attractive than green or control females. Additionally, independent of band color, males who exhibited greater T differences initiated courtship sooner and spent more time closest to females. However, courtship initiation and time spent near females were not correlated with band color. Overall, our results suggest that female attractiveness can influence male reproductive physiology, but the presence of a female may trigger male courtship behavior.
ContributorsBero-Buell, Brianna Danielle (Author) / McGraw, Kevin (Thesis director) / Deviche, Pierre (Committee member) / Ligon, Russell (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2014-05
Description
Historically, the study of cognition has focused on species-specific learning, memory, problem-solving and decision-making capabilities, and emphasis was placed on the few high-performing individuals who successfully completed cognitive tasks. Studies often deemed the success of a small fraction of individuals as suggestive of the cognitive capacity of the entire species. Recently though, interest in individual variation in cognitive ability within species has increased. This interest has emerged concomitantly with studies of variation in animal personalities (i.e. behavioral syndromes). Cognitive ability may be closely tied to personality because the mechanisms by which an individual perceives and uses environmental input (cognition) should influence how that individual consistently responds to various ecological demands (personality). However, empirical support for links between animal cognition and behavioral syndromes is currently lacking. I examined individual variation in cognition and personality in male veiled chameleons, Chamaeleo calyptratus. I considered three axes of personality (aggression, activity, and exploratory behavior) and cognition in a foraging context using visual cues − specifically, the ability to associate a color with a food reward. I found that aggression was positively correlated with the proportion of correct choices and number of consecutive correct choices. Also, one measure of exploration (the number of vines touched in a novel environment) was correlated negatively with the proportion of correct choices and positively with the number of consecutive incorrect decisions. My investigation suggests that more aggressive, less exploratory chameleons were more successful learners, and that there exists a shared pathway between these personality traits and cognitive ability.
ContributorsBruemmer, Sarah Adele (Author) / McGraw, Kevin (Thesis director) / Rutowski, Ronald (Committee member) / Ligon, Russell (Committee member) / Barrett, The Honors College (Contributor) / School of Human Evolution and Social Change (Contributor) / School of Life Sciences (Contributor)
Created2013-05
Description
Urbanization exposes wildlife to many unfamiliar environmental conditions, including the presence of novel structures and food sources. Adapting to or thriving within such anthropogenic modifications may involve cognitive skills, whereby animals come to solve novel problems while navigating, foraging, etc. The increased presence of humans in urban areas is an additional environmental challenge that may potentially impact cognitive performance in wildlife. To date, there has been little experimental investigation into how human disturbance affects problem solving in animals from urban and rural areas. Urban animals may show superior cognitive performance in the face of human disturbance, due to familiarity with benign human presence, or rural animals may show greater cognitive performance in response to the heightened stress of unfamiliar human presence. Here, I studied the relationship between human disturbance, urbanization, and the ability to solve a novel foraging problem in wild-caught juvenile house finches (Haemorhous mexicanus). This songbird is a successful urban dweller and native to the deserts of the southwestern United States. In captivity, finches captured from both urban and rural populations were presented with a novel foraging task (sliding a lid covering their typical food dish) and then exposed to regular periods of high or low human disturbance over several weeks before they were again presented with the task. I found that rural birds exposed to frequent human disturbance showed reduced task performance compared to human-disturbed urban finches. This result is consistent with the hypothesis that acclimation to human presence protects urban birds from reduced cognition, unlike rural birds. Some behaviors related to solving the problem (e.g. pecking at and eying the dish) also differed between urban and rural finches, possibly indicating that urban birds were less neophobic and more exploratory than rural ones. However, these results were unclear. Overall, these findings suggest that urbanization and acclimation to human presence can strongly predict avian response to novelty and cognitive challenges.
ContributorsCook, Meghan Olivia (Author) / McGraw, Kevin (Thesis director) / Bimonte-Nelson, Heather (Committee member) / Weaver, Melinda (Committee member) / Barrett, The Honors College (Contributor) / School of Life Sciences (Contributor)
Created2015-05