While direct measurements of energetic demands are nearly impossible to collect on large cetaceans, comprehensive bioenergetic models can give insights on such parameters by combining physiological and ecological knowledge. This model was developed to estimate necessary food intake of gray whales, Eschrichtius robustus, of the Eastern North Pacific stock. Field Metabolic Rates (FMR) for gray whales were first estimated based on various assumptions (e.g. volumetric representation of gray whales, extent of their feeding season, and blubber depth distribution) using morphometric data, energetic costs, and food assimilation according to age and gender specific requirements. Food intake rates for gray whales of varying maturity and gender were then estimated based on FMR and caloric value of prey and compared to food intake rates of previous studies. Monte Carlo simulations and sensitivity analysis were performed to assess the model's predictions compared to observed field data from previous studies. Predicted average food intakes for adult male, pregnant/ lactating female, and immature whales were 475 ± 300, 525 ± 300 and 600 ± 300 kg d-1, respectively. Estimated blubber depths resulting from these food intakes were comparable to field data obtained from whaling data. Sensitivity analysis indicated food intake, from all parameters, as having the highest impact on the percent change in ending mass from a simulation. These food intake estimates are similar to those found in a previous study and fall within the range of food intake per body mass observed in other species of cetaceans. Though thermoregulation can be a factor in some cetaceans, it appears not to be an additional cost for gray whales as the present model's predicted lower critical temperatures for the whales (TLC) were below ambient temperatures. With temperatures increasing in the Bering Sea, the main prey of gray whales, ampeliscid amphipods, could be adversely affected, possibly resulting in increased food shortages leading to a surge in gray whale strandings.

Aquatic organisms in response to toxic insults from environmental pollutants activate defence systems including the aryl hydrocarbon receptor (AhR) in an attempt to metabolize and excrete these toxicants and their metabolites. These detoxification mechanisms however may come with certain energetic costs. I hypothesize that the activation of the AhR by β-Naphthoflavone (β-NF), a model AhR agonist, results in increased energetic costs requiring metabolic reorganization in rainbow trout hepatocytes. While the results obtained suggest that there are no significant energetic costs of AhR activation, analysis of enzyme activities suggests possible metabolic reorganization. This study also showed significant changes in cellular processes in hepatocytes over the incubation periods which previously were not reported. Furthermore, for the first time in fish hepatocytes, metabolic flux analysis (MFA) was used to examine intra-cellular metabolism, the applicability of which is discussed.

Aquatic organisms in response to toxic insults from environmental pollutants activate defence systems including the aryl hydrocarbon receptor (AhR) in an attempt to metabolize and excrete these toxicants and their metabolites. These detoxification mechanisms however may come with certain energetic costs. I hypothesize that the activation of the AhR by β-Naphthoflavone (β-NF), a model AhR agonist, results in increased energetic costs requiring metabolic reorganization in rainbow trout hepatocytes. While the results obtained suggest that there are no significant energetic costs of AhR activation, analysis of enzyme activities suggests possible metabolic reorganization. This study also showed significant changes in cellular processes in hepatocytes over the incubation periods which previously were not reported. Furthermore, for the first time in fish hepatocytes, metabolic flux analysis (MFA) was used to examine intra-cellular metabolism, the applicability of which is discussed.

Male reproductive success in many mammals depends on their ability to allocate sufficient energetic resources to mating competition. Such costs are particularly pronounced in species with high levels of sexual body dimorphism, intense polygyny and distinct breeding seasons. I tested the hypothesis that male reproductive effort incurs significant energetic costs in wild chimpanzees (Pan troglodytes), a species with moderate sexual dimorphism, promiscuous mating and lack of breeding seasonality. My field studies combined behavioral observations on male chimpanzee behavior with non-invasive sampling of urinary C-peptide (UCP). UCP is a biomarker of insulin production that indexes individual energy balance. This dissertation contributes to the understanding of UCP as an energy assay by (1) validating the application of UCP for assessing dietary quality in bonobos (Pan paniscus) at Kokolopori, DRC and (2) providing a detailed assessment of diurnal variation in UCP levels in relation to short-term changes in food intake in chimpanzees at Kanyawara, Kibale NP, Uganda. I used UCP measurements in conjunction with full-day focal observations of male chimpanzees to assess the energetic costs of male-male competition for status and mating opportunities. Data on feeding time and rates of aggression suggested that males experience a reduction in energy intake and an increase in energy expenditure when highly attractive parous females were in estrus. UCP data supported these conclusions because males had lower UCP levels on mating days, and rates of aggression were negatively associated with UCP levels. Mean daily party size was also associated with low UCP levels, controlling for the presence of estrous females. Habitat-wide availability of preferred fruits was positively associated with male rates of aggression suggesting that energy availability mediates male investment towards energetically costly competitive behaviors. Contrary to expectations males who were most successful in obtaining copulations (high-ranking males) did not suffer higher energetic costs than lower-ranking males during periods of mating competition. Costs or reproductive effort include both direct competition for matings and long-term competition over social status. Maintenance of social rank over long periods appears to be particularly important in this slow-reproducing, long-lived and nonseasonally breeding primate. / Human Evolutionary Biology

Aquatic organisms in response to toxic insults from environmental pollutants activate defence systems including the aryl hydrocarbon receptor (AhR) in an attempt to metabolize and excrete these toxicants and their metabolites. These detoxification mechanisms however may come with certain energetic costs. I hypothesize that the activation of the AhR by β-Naphthoflavone (β-NF), a model AhR agonist, results in increased energetic costs requiring metabolic reorganization in rainbow trout hepatocytes. While the results obtained suggest that there are no significant energetic costs of AhR activation, analysis of enzyme activities suggests possible metabolic reorganization. This study also showed significant changes in cellular processes in hepatocytes over the incubation periods which previously were not reported. Furthermore, for the first time in fish hepatocytes, metabolic flux analysis (MFA) was used to examine intra-cellular metabolism, the applicability of which is discussed.

Temperature is arguably the most important abiotic factor influencing the embryonic development in ectothermic species. Incubation temperature has demonstrated effects on offspring phenotypes in ectotherms, including traits such as sex, size, shape, colouration and post-hatch growth and survival. However, in endotherms the influence temperature has on development is relatively unexplored due to the narrow range of temperatures that embryonic endotherms are exposed to during develop. Megapode birds utilize environmental heat sources to incubate their eggs and therefore provide a potential model to test how temperature influences embryonic development and offspring phenotypes in endotherms. I used the Australian Brush-turkey (Alectura lathami), a megapode bird that incubates its eggs in mounds of soil and leaf litter to investigate the effects of temperature on embryonic development and chick morphology. Previous reports of Australian Brush-turkey incubation mound temperatures relied on spot measurements and theoretical modeling and thus have not provided a comprehensive examination of the range of temperatures Brush-turkey embryos are exposed to and how these might vary during the course of incubation. Therefore to examine the range of temperatures experienced by developing embryos I continuously recorded the temperature of eggs and mound material at naturally occurring positions within incubation mounds over the full developmental period. As in previous studies I found the average incubation temperature to be about 34°C, however egg temperatures typically fluctuated more than previously reported or predicted from modeling. The thermal tolerance of Brush-turkeys is remarkable compared to non-megapode birds, with embryos developing successfully despite prolonged exposure to sub-optimal temperatures over the range 25-40°C. I also demonstrated that the incubation period was negatively correlated with mean incubation temperature. To simplify the examination of temperature effects on embryonic development, constant temperature artificial incubation of Brush-turkey eggs was used to determine influence of incubation temperature on the energetics of embryonic development and the sex ratio, morphology and chemical composition of chicks. Because initial investigation of mound temperatures determined the mean incubation temperature in Brush-turkeys to be 34°C this was used as the preferred temperature for constant temperature incubation with 32°C and 36°C representing low and high temperatures respectively. Previously, the sex ratio of Brush-turkey chicks at hatching was shown to be temperature dependent. A thermally sensitive period early in development resulted in more females hatching from high temperature and more males hatching from low temperatures with an equal ratio at the preferred temperature. Using molecular sexing techniques to determine the sex of both failed embryos and chicks that hatched, I established that at laying the sex ratio of eggs was 50:50, and that temperature-dependent sex-biased embryo mortality was the mechanism behind the skewed sex ratio of chicks hatching from non-preferred temperatures. Low incubation temperature increased female embryonic mortality and high incubation temperature increased male embryonic mortality. This represents a novel mechanism operating to alter sex ratios in a bird species and offers an unparalleled system to explore sex allocation theory. It is well established that temperature influences the rate of development and the morphology of offspring in reptilian species. Also, in a previous study using artificially incubated Brush-turkey eggs, temperature was found to affect the mass of chicks but not their size (linear dimensions). This finding suggests that at different incubation temperatures the amount of yolk converted into tissue during embryonic development is influenced by incubation temperature. I tested this hypothesis by incubating eggs at different constant temperatures and found high incubation temperatures produce chicks with lighter yolk-free bodies and heavier residual yolks but similar linear dimensions compared to chicks hatching from lower temperatures. Because eggs incubated at low temperatures have longer incubation periods, I hypothesized the proportion of lipid in the yolk-free body would be higher in chicks emerging from eggs incubated at low temperature because more time is available for the conversion of yolk to fat bodies during embryonic development. This hypothesis was not supported as the composition of yolk-free chicks (total water, lipid, protein and ash) was not temperature dependent. A previous study in Malleefowl (Leipoa ocellata), another megapode bird, found that the total energetic cost of production was influenced by incubation temperature. Such that embryos developing at low temperatures required 72% more energy than embryos developing at high temperatures. However these findings were contrary to expectation from studies of reptilian incubation where the energetic cost of development is independent of temperature. Therefore I tested the hypothesis that the total energetic cost of development is temperature dependent in the Australian Brush-turkey. I used bomb calorimetry to measure the energy content of freshly laid eggs and of chicks (both the yolk-free body and residual yolk) that had hatched from eggs incubated 32oC, 34oC and 36oC. I found that the total energy content of chicks at hatching was greater in chicks emerging from eggs incubated at 34oC and 36oC compared to eggs incubated at 32oC. My thesis work demonstrated that incubation temperature is more variable for Brush-turkey embryos than for non-megapode birds and that even a small difference in temperature can have important effects on chick sex ratios, morphology and energy reserves. I have shown that incubation under artificial constant temperature conditions can significantly alter the developmental trajectories and phenotypic outcomes for chicks. In addition to laboratory based work, future studies should continue to examine how embryonic development and chick attributes are influenced by temperatures experienced under natural incubation conditions. Furthermore, investigation is required to determine how incubation temperature induced differences in hatchling phenotypes influence the post-hatch grow and fitness of chicks.

Autotomy (self-induced loss) of body parts has evolved independently as a predator defense mechanism in several major animal phyla. The mechanism among vertebrates, including 13 of the 20 recognized lizard families, is tail autotomy. Its occurrence among the majority of lizard families offers an excellent opportunity to examine the effects of a major selective force on the ecology and evolution of a group of organisms. The research of this study was designed to examine experimentally (i) the function of tail autotomy, (ii) the function of autotomized tail movement, (iii) the energetics of autotomized tail movement, and (iv) the energetic costs of autotomy of an energy-rich tail to reproduction.

Aquatic organisms in response to toxic insults from environmental pollutants activate defence systems including the aryl hydrocarbon receptor (AhR) in an attempt to metabolize and excrete these toxicants and their metabolites. These detoxification mechanisms however may come with certain energetic costs. I hypothesize that the activation of the AhR by β-Naphthoflavone (β-NF), a model AhR agonist, results in increased energetic costs requiring metabolic reorganization in rainbow trout hepatocytes. While the results obtained suggest that there are no significant energetic costs of AhR activation, analysis of enzyme activities suggests possible metabolic reorganization. This study also showed significant changes in cellular processes in hepatocytes over the incubation periods which previously were not reported. Furthermore, for the first time in fish hepatocytes, metabolic flux analysis (MFA) was used to examine intra-cellular metabolism, the applicability of which is discussed.

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