1,554 results match your criteria Physiological and biochemical zoology : PBZ[Journal]


Variation in Corticosterone Levels in Two Species of Breeding Albatrosses with Divergent Life Histories: Responses to Body Condition and Drivers of Foraging Behavior.

Physiol Biochem Zool 2019 Mar/Apr;92(2):223-238

Corticosterone (CORT) is a glucocorticoid hormone that maintains energy balance and can modulate foraging behaviors in seabirds. However, CORT responses are not always predictable under similar biophysical conditions and do not necessarily influence the same behaviors across breeding stages and species. To enhance our understanding of CORT's role as a proximate determinant of foraging behavior and energy maintenance, we examined the relationships between body condition, CORT, foraging behavior, and foraging success between two sympatric breeding albatross species with differing foraging strategies and life histories, the Campbell albatross (Thalassarache impavida) and the gray-headed albatross (Thalassarache chrysostoma), from Campbell Island, New Zealand. Read More

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http://dx.doi.org/10.1086/702656DOI Listing
February 2019

Dynamics of Individual Fatty Acids in Muscle Fat Stores and Membranes of a Songbird and Its Functional and Ecological Importance.

Physiol Biochem Zool 2019 Mar/Apr;92(2):239-251

Although tissue fatty acid (FA) composition has been linked to whole-animal performance (e.g., aerobic endurance, metabolic rate, postexercise recovery) in a wide range of animal taxa, we do not adequately understand the pace of changes in FA composition and its implications for the ecology of animals. Read More

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http://dx.doi.org/10.1086/702667DOI Listing
February 2019
1 Read

Physiological Regulation of Growth during Social Ascension in a Group-Living Fish.

Physiol Biochem Zool 2019 Mar/Apr;92(2):211-222

2 Department of Biology, University of Ottawa, 30 Marie Curie Private, Ottawa, Ontario K1N 6N5, Canada.

In social groups, dominant animals typically are larger and have better access to resources than subordinates. When subordinates are given the opportunity to ascend to a dominant position, they will elevate their rates of growth to help secure dominance. This study investigated the physiological mechanisms facilitating this increased growth. Read More

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http://dx.doi.org/10.1086/702338DOI Listing
February 2019

Mizutama: A Quick, Easy, and Accurate Method for Counting Erythrocytes.

Physiol Biochem Zool 2019 Mar/Apr;92(2):206-210

2 Departamento de Zoología, Universidad de Granada, E-18071, Granada, Spain.

Hematological profiles are routinely used to assess the health status of animals. Several methods have been developed for blood cell counting, but they are typically expensive and/or time-consuming. Here, we present a free image-processing software, Mizutama, developed for counting cells in photographs of blood smears. Read More

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https://www.journals.uchicago.edu/doi/10.1086/702666
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http://dx.doi.org/10.1086/702666DOI Listing
February 2019
1 Read

Overwintering Red Velvet Mites Are Freeze Tolerant.

Physiol Biochem Zool 2019 Mar/Apr;92(2):201-205

Although many arthropods are freeze tolerant (able to withstand internal ice), small-bodied terrestrial arthropods such as mites are thought to be constrained to freeze avoidance. We field-collected active adult red velvet mites, Allothrombium sp. (Trombidiidae), in winter in Southwestern Ontario, Canada, where temperatures drop below -20°C. Read More

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http://dx.doi.org/10.1086/702655DOI Listing
February 2019

Lizards at the Peak: Physiological Plasticity Does Not Maintain Performance in Lizards Transplanted to High Altitude.

Physiol Biochem Zool 2019 Mar/Apr;92(2):189-200

Warming climates are facilitating the range expansion of many taxa to habitats that were formerly thermally inhospitable, including to higher latitudes and elevations. The potential for such colonization, however, varies widely among taxa. Because environmental factors may interact to affect colonization potential, an understanding of underlying physiological and behavioral mechanisms is necessary to predict how species will respond to potentially suitable habitats. Read More

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http://dx.doi.org/10.1086/701793DOI Listing
February 2019

Next-Generation Ecological Immunology.

Physiol Biochem Zool 2019 Mar/Apr;92(2):177-188

The application of next-generation sequencing (NGS) to the study of whole genomes and transcriptomes is becoming commonplace in molecular biology and molecular medicine. Over the past decade, these technologies have become more accessible to the broader biological community as the cost of NGS has decreased significantly and the availability of ready-to-use library preparation kits and user-friendly bioinformatic tools has increased. Indeed, these technologies are starting to be deployed in the study of ecological systems and immune function and have already yielded new discoveries and insights. Read More

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https://www.journals.uchicago.edu/doi/10.1086/702440
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http://dx.doi.org/10.1086/702440DOI Listing
February 2019
2 Reads

Ecologically Relevant Temperature Ramping Rates Enhance the Protective Heat Shock Response in an Intertidal Ectotherm.

Physiol Biochem Zool 2019 Mar/Apr;92(2):152-162

Thermal stress experiments are essential for understanding organisms' thermal limits and the physiological processes that contribute to establishing those limits. Experiments typically employ either an abrupt transfer to near-lethal temperatures or a gradually increasing thermal exposure. In the current study, we used three populations of the intertidal copepod Tigriopus californicus that are known to differ in upper thermal tolerance to investigate the effects of gradual versus abrupt thermal exposures on survivorship, developmental time, and heat shock protein gene expression. Read More

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http://dx.doi.org/10.1086/702339DOI Listing
February 2019

Can a Terrestrial Ectoparasite Disperse with Its Marine Host?

Physiol Biochem Zool 2019 Mar/Apr;92(2):163-176

One of the most extreme examples of parasite adaptation comes from terrestrial ectoparasites exploiting marine hosts. Despite the ubiquity of such ectoparasitism and its ecological and evolutionary importance, investigations of the responses of ectoparasites to conditions encountered on their hosts are rare. In the case of penguins and their ticks, current understanding suggests that ticks freely parasitize their hosts on land but are incapable of surviving extended oceanic journeys. Read More

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http://dx.doi.org/10.1086/701726DOI Listing
February 2019
1 Read

Short-Term Climate Variation Drives Baseline Innate Immune Function and Stress in a Tropical Bird: A Reactive Scope Perspective.

Physiol Biochem Zool 2019 Mar/Apr;92(2):140-151

Investment in immune function can be costly, and life-history theory predicts trade-offs between immune function and other physiological demands. Environmental heterogeneity may constrain or change the optimal strategy and thereby alter baseline immune function (possibly mediated by stress responses). We tested several hypotheses relating variation in climatic, ecological, and social environments to chronic stress and levels of baseline innate immunity in a wild, cooperatively breeding bird, the purple-crowned fairy-wren (Malurus coronatus coronatus). Read More

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http://dx.doi.org/10.1086/702310DOI Listing
February 2019
1 Read

Do Gulf Toadfish Use Pulsatile Urea Excretion to Chemically Communicate Reproductive Status?

Physiol Biochem Zool 2019 Mar/Apr;92(2):125-139

Gulf toadfish (Opsanus beta) are exceptionally capable of switching from excreting ammonia as their primary nitrogenous waste to excreting predominantly urea in distinct pulses across the gill. Previous studies suggest that these urea pulses may be used for intraspecific chemical communication. To determine whether pulsatile urea excretion communicates reproductive status, toadfish were sexed using ultrasound and delivered conspecific-conditioned seawater (CC-SW) that previously housed a conspecific of the opposite sex, a conspecific chemical alarm cue (avoidance control), or a prey cue (attraction control). Read More

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http://dx.doi.org/10.1086/701497DOI Listing
February 2019
1 Read

Sterile Capsule-Egg Cocoon Covering Constitutes an Antibacterial Barrier for Spider Parasteatoda tepidariorum Embryos.

Physiol Biochem Zool 2019 Jan/Feb;92(1):115-124

Coexistence of organisms and pathogens has resulted in the evolution of efficient antimicrobial defense, especially at the embryonic stage. This investigation aimed to substantiate the hypothesis that the layers of silk in a spider cocoon play a role in the immunity of the embryos against microorganisms present in the external environment. A two-step interdisciplinary attempt has been made. Read More

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http://dx.doi.org/10.1086/701390DOI Listing
January 2019
2 Reads

Assessment of Trade-Offs between Simultaneous Immune Challenges in a Slow-Living Subterranean Rodent.

Physiol Biochem Zool 2019 Jan/Feb;92(1):92-105

The coexistence of two or more infectious agents in the same host is common in nature. Given this, the study of trade-offs within the immune system itself is key to understanding how immune defenses act in wild species in their natural environment. Here we assessed the possible trade-off between an inflammatory response (induced by phytohemagglutinin [PHA]; involving innate and adaptive responses in the study species) and an antibody response (induced by sheep red blood cells [SRBC]; adaptive response) in a slow-living subterranean rodent, the Talas tuco-tuco (Ctenomys talarum Thomas, 1898). Read More

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http://dx.doi.org/10.1086/701320DOI Listing
January 2019
1 Read

Physiological and Immune Responses of Free-Living Temperate Birds Provided a Gradient of Food Supplementation.

Physiol Biochem Zool 2019 Jan/Feb;92(1):106-114

Food availability might sometimes be unpredictable for wild birds. To alleviate this possible food limitation, millions of households in North America provide food supplementation to bird populations. However, the ecoimmunological impacts of this supplementation on free-living birds are largely unclear. Read More

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https://www.journals.uchicago.edu/doi/10.1086/701389
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http://dx.doi.org/10.1086/701389DOI Listing
January 2019
4 Reads

Short-Term Sleep Loss Alters Cytokine Gene Expression in Brain and Peripheral Tissues and Increases Plasma Corticosterone of Zebra Finch (Taeniopygia guttata).

Physiol Biochem Zool 2019 Jan/Feb;92(1):80-91

Lack of sleep incurs physiological costs that include increased inflammation and alterations in the hypothalamic-pituitary-adrenal axis. Specifically, sleep restriction or deprivation leads to increased pro-inflammatory cytokine expression and elevated glucocorticoids in rodent models, but whether birds exact similar costs is unknown. In this study, we examined whether zebra finch (Taeniopygia guttata), an avian model species, exhibits physiological costs of sleep loss by using a novel automated sleep fragmentation/deprivation method, wherein a horizontal wire sweeps across a test cage to disrupt sleep every 120 s. Read More

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https://www.journals.uchicago.edu/doi/10.1086/701170
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http://dx.doi.org/10.1086/701170DOI Listing
December 2018
14 Reads

Trematode Parasite Infection Affects Temperature Selection in Aquatic Host Snails.

Physiol Biochem Zool 2019 Jan/Feb;92(1):71-79

Animals infected by parasites or pathogens can exhibit altered behaviors that may reduce the costs of infection to the host or represent manipulations that benefit the parasite. Given that temperature affects many critical physiological processes, changes in thermoregulatory behaviors are an important consideration for infected hosts, especially ectotherms. Here we examined the temperature choices of freshwater snails (Helisoma trivolvis) that were or were not infected by a trematode (flatworm) parasite (Echinostoma trivolvis). Read More

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http://dx.doi.org/10.1086/701236DOI Listing
November 2018
2 Reads

Dietary Protein and Carbohydrates Affect Immune Function and Performance in a Specialist Herbivore Insect (Manduca sexta).

Physiol Biochem Zool 2019 Jan/Feb;92(1):58-70

Nutrition structures ecology and evolution across all scales of biological organization. It is well known that nutrition can have direct effects on performance and fitness, but indirect effects on physiological systems that mediate biotic interactions have been studied less frequently. Here, we focus on the interaction between nutrition, performance, and the immune system in a specialist herbivorous insect, Manduca sexta. Read More

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https://www.journals.uchicago.edu/doi/10.1086/701196
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http://dx.doi.org/10.1086/701196DOI Listing
November 2018
14 Reads

How Individual Variation in Host Tolerance Affects Competence to Transmit Parasites.

Physiol Biochem Zool 2019 Jan/Feb;92(1):49-57

Tolerance, or the maintenance of host health or fitness at a given parasite burden, has often been studied in evolutionary and medical contexts, particularly with respect to effects on the evolution of parasite virulence and individual patient outcomes. These bodies of work have provided insight about tolerance for evolutionary phenomena (e.g. Read More

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https://www.journals.uchicago.edu/doi/10.1086/701169
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http://dx.doi.org/10.1086/701169DOI Listing
November 2018
9 Reads

Handling Stress and Sample Storage Are Associated with Weaker Complement-Mediated Bactericidal Ability in Birds but Not Bats.

Physiol Biochem Zool 2019 Jan/Feb;92(1):37-48

Variation in immune defense influences infectious disease dynamics within and among species. Understanding how variation in immunity drives pathogen transmission among species is especially important for animals that are reservoir hosts for zoonotic pathogens. Bats, in particular, have a propensity to host serious viral zoonoses without developing clinical disease themselves. Read More

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https://www.journals.uchicago.edu/doi/10.1086/701069
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http://dx.doi.org/10.1086/701069DOI Listing
November 2018
10 Reads

Seasonality of Immunological and Health-State Parameters of Wild Broadnose Sevengill Shark, Notorynchus cepedianus.

Physiol Biochem Zool 2019 Jan/Feb;92(1):24-36

Seasonal fluctuation in environmental parameters can influence immune responses of vertebrates and consequently influence their health and disease resistance. Although seasonality of immune function is well documented in a broad range of vertebrate taxa, this information remains virtually unexplored in cartilaginous fish. Here we examine seasonal variation in immune and general-health parameters of free-living adult broadnose sevengill sharks, Notorynchus cepedianus, along an annual cycle. Read More

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https://www.journals.uchicago.edu/doi/10.1086/700573
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http://dx.doi.org/10.1086/700573DOI Listing
November 2018
10 Reads

Heightened Immune System Function in Polar Bears Using Terrestrial Habitats.

Physiol Biochem Zool 2019 Jan/Feb;92(1):1-11

Climate change is altering the distribution of some wildlife species while warming temperatures are facilitating the northward expansion of pathogens, potentially increasing disease risk. Melting of Arctic sea ice is increasingly causing polar bears (Ursus maritimus) of the southern Beaufort Sea (SBS) to spend summer on land, where they may encounter novel pathogens. Here, we tested whether SBS polar bears on shore during summer exhibited greater immune system activity than bears remaining on the sea ice. Read More

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http://dx.doi.org/10.1086/698996DOI Listing
November 2018
1 Read

Interrelations among Multiple Metrics of Immune and Physiological Function in a Squamate, the Common Gartersnake (Thamnophis sirtalis).

Physiol Biochem Zool 2019 Jan/Feb;92(1):12-23

The field of ecoimmunology has made it clear that individual and ecological contexts are critical for interpreting an animal's immune response. In an effort to better understand the relevance of commonly used immunological assays, we tested how different metrics of immunity and physiological function were interrelated in naturally parasitized individuals of a well-studied reptile, the common gartersnake (Thamnophis sirtalis). Overall, we found that bactericidal ability, an integrative measure of innate immunity, was often correlated with more specific immunological and physiological tests (lysis and oxidative stress) but was not related to tissue-level inflammation that was determined by histopathology. Read More

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http://dx.doi.org/10.1086/700396DOI Listing
November 2018
1 Read

Dynamics of Gene Expression Responses for Ion Transport Proteins and Aquaporins in the Gill of a Euryhaline Pupfish during Freshwater and High-Salinity Acclimation.

Physiol Biochem Zool 2018 Nov/Dec;91(6):1148-1171

Pupfishes (genus Cyprinodon) evolved some of the broadest salinity tolerances of teleost fishes, with some taxa surviving in conditions from freshwater to nearly 160 ppt. In this study, we examined transcriptional dynamics of ion transporters and aquaporins in the gill of the desert Amargosa pupfish (Cyprinodon nevadensis amargosae) during rapid salinity change. Pupfish acclimated to 7. Read More

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https://www.journals.uchicago.edu/doi/10.1086/700432
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http://dx.doi.org/10.1086/700432DOI Listing
January 2019
7 Reads

Seasonal Shifts in Reproduction Depend on Prey Availability for an Income Breeder.

Physiol Biochem Zool 2018 Nov/Dec;91(6):1129-1147

The evolution of reproductive strategies depends on local environmental conditions. When environments are seasonal, selection favors individuals that align changes in key reproductive traits with seasonal shifts in habitat quality. Offspring habitat quality can decline through the season, and increased maternal provisioning to late-produced offspring may compensate. Read More

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http://dx.doi.org/10.1086/700341DOI Listing
January 2019
1 Read

Do Metabolic Traits, Vulnerability to Angling, or Capture Method Explain Boldness Variation in Eurasian Perch?

Physiol Biochem Zool 2018 Nov/Dec;91(6):1115-1128

The pace-of-life syndrome (POLS) concept predicts that individuals with high baseline metabolic rates demonstrate high boldness, aggressiveness, and activity, especially in food acquisition, with associated relatively greater energy requirements. In fishes, these behaviors may increase individual vulnerability to angling. To test the predictions of the POLS concept, we quantified individual standard metabolic rate (SMR) and boldness in both wild-caught and hatchery-reared Eurasian perch (Perca fluviatilis). Read More

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http://dx.doi.org/10.1086/700434DOI Listing
January 2019
2 Reads

The Influence of Temperature on Embryonic Respiration, Growth, and Sex Determination in a Western Australian Population of Green Turtles (Chelonia mydas).

Physiol Biochem Zool 2018 Nov/Dec;91(6):1102-1114

The thermal environment of sea turtle embryos has marked effects on many aspects of their development and energetics and has consequences for posthatching stages. Here we incubated Chelonia mydas embryos from Ningaloo Reef in Western Australia at a range of temperatures (27°, 29°, 30°, 31°, 32°, and 30° ± 5°C) to determine development rates and the pivotal temperature for sex determination. We also measured embryonic growth, oxygen consumption, and carbon dioxide production throughout development at 27° and 31°C. Read More

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http://dx.doi.org/10.1086/700433DOI Listing
January 2019
2 Reads

Ploidy Has Minimal Effect on Hypoxia Tolerance at High Temperature in Rainbow Trout (Oncorhynchus mykiss).

Physiol Biochem Zool 2018 Nov/Dec;91(6):1091-1101

Polyploidy is an important driver of evolutionary change (generally via tetraploidy) and also serves a practical role in aquaculture and fisheries management (via triploidy). Fundamental changes in cell size and number that accompany polyploidy are predicted to affect cellular and whole-animal physiology due to constraints placed on surface-mediated processes at the cellular level, potentially altering environmental tolerances and optima. The aim of this study was to determine whether the documented reduction in thermal tolerance of aquatic polyploids is a result of their being less hypoxia tolerant. Read More

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https://www.journals.uchicago.edu/doi/10.1086/700218
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http://dx.doi.org/10.1086/700218DOI Listing
January 2019
5 Reads

Adult Provisioning Influences Nestling Corticosterone Levels in Florida Scrub Jays (Aphelocoma coerulescens).

Physiol Biochem Zool 2018 Nov/Dec;91(6):1083-1090

We studied Florida scrub jay (Aphelocoma coerulescens) nestlings to examine the relationship between parental feeding rates and levels of corticosterone (CORT), a metabolic and stress-related steroid hormone hypothesized to play a role in mediating begging behavior. It has been documented that nutritional deficiency results in increased glucocorticoid levels in nestling birds. Further, previous studies have found that CORT levels of Florida scrub jay nestlings are negatively correlated with parental nest attendance and provisioning rates; however, the behavioral observations were made several days before the collection of samples to assess CORT levels. Read More

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http://dx.doi.org/10.1086/700258DOI Listing
January 2019
1 Read

Functional Divergence of Mitochondria and Coevolution of Genomes: Cool Mitochondria in Hot Lizards.

Physiol Biochem Zool 2018 Sep/Oct;91(5):1068-1081

Mitochondria play a key role in the ecology and evolution of species through their influence on aerobic metabolism. Mitochondrial DNA (mtDNA) and nuclear genomes must interact for optimal functioning of oxidative phosphorylation to produce ATP, and breakdown of coadaptation components from each may have important evolutionary consequences for hybridization. Introgression of mitochondria in natural populations through hybridization with unidirectional backcrossing allows the testing of coadaptation of mitochondria to different nuclear backgrounds. Read More

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http://dx.doi.org/10.1086/699918DOI Listing
December 2018
1 Read

Does Basal Metabolism Set the Limit for Metabolic Downregulation during Torpor?

Physiol Biochem Zool 2018 Sep/Oct;91(5):1057-1067

The evolution of endothermic thermoregulation is rooted in the processes involving high metabolism, which allows the maintenance of high and stable body temperatures (T). In turn, selection for high endothermic metabolism correlates with increased size of metabolically active organs and thus with high basal metabolic rate (BMR). Endothermic animals are characterized by an MR several times that of similar-sized ectotherms. Read More

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http://dx.doi.org/10.1086/699917DOI Listing
December 2018
1 Read

Repeatable Interindividual Variation in Hypoxia Tolerance in the Gulf Killifish, Fundulus grandis.

Physiol Biochem Zool 2018 Sep/Oct;91(5):1046-1056

The capacity of fishes to tolerate low oxygen (hypoxia) through behavioral and physiological adjustments varies among species in a fashion that correlates with oxygen availability in their natural habitats. Less is known about variation in hypoxia tolerance within a species, but it is expressly this interindividual variation that will determine which individuals will survive during severe hypoxia. Here, we measured aquatic surface respiration (ASR) and loss of equilibrium (LOE), two common indexes of hypoxia tolerance of fishes, in gulf killifish, Fundulus grandis, subjected to multiple trials of a highly reproducible hypoxia protocol over a period of 6-8 wk. Read More

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http://dx.doi.org/10.1086/699596DOI Listing
December 2018
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Sex-Specific Effects of Incubation Temperature on Embryonic Development of Zebra Finch (Taeniopygia guttata) Embryos.

Physiol Biochem Zool 2018 Sep/Oct;91(5):1036-1045

In oviparous species, the embryonic environment-particularly temperature-can alter phenotype and survival of an individual by affecting its size as well as its metabolic rate. Previous studies have shown that incubation temperatures can affect sex ratio in birds; specifically, low incubation temperatures were shown to produce a male-biased sex ratio in zebra finches (Taeniopygia guttata) possibly because of a higher pre- or postnatal mortality rate in females. We hypothesized that sexes respond differently to suboptimal incubation temperature, leading to a male-biased sex ratio. Read More

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http://dx.doi.org/10.1086/699741DOI Listing
December 2018
3 Reads

Melanin-Based Skin Coloration Predicts Antioxidant Capacity in the Brown Trout (Salmo trutta).

Physiol Biochem Zool 2018 Sep/Oct;91(5):1026-1035

In many vertebrate species, individuals exhibit large variation in the degree of melanin-based coloration on their body. Dark and pale individuals differ in diverse physiological and behavioral traits, suggesting that melanic coloration may reveal individual quality. However, research into the relationships between physiological and skin traits, in terms of melanin-based skin coloration, in wild fish is scant. Read More

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http://dx.doi.org/10.1086/699522DOI Listing
December 2018
2 Reads

Covariation between Thermally Mediated Color and Performance Traits in a Lizard.

Physiol Biochem Zool 2018 Sep/Oct;91(5):1013-1025

Physiological changes in response to environmental cues are not uncommon. Temperature has strong, predictable effects on many traits, such that many traits in ectotherms follow stereotyped thermal performance curves in response to increasing temperature. The prairie lizard-an abundant lizard throughout the central United States-has thermally sensitive, blue abdominal and throat patches. Read More

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http://dx.doi.org/10.1086/699616DOI Listing
December 2018
2 Reads

Thermal Imaging Reveals Changes in Body Surface Temperatures of Blacktip Sharks (Carcharhinus limbatus) during Air Exposure.

Physiol Biochem Zool 2018 Sep/Oct;91(5):1005-1012

Fish physiology is significantly affected by temperature variability. During fisheries interactions, fish are often exposed to air and subjected to rapid temperature changes. Fish thermal dynamics during such exposure, and the possible outcomes to their physiology, depend on how heat is distributed across their bodies, the speed at which their body temperatures change, and the size of the individual. Read More

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http://dx.doi.org/10.1086/699484DOI Listing
December 2018
1 Read

Effects of Weather Conditions on Oxidative Stress, Oxidative Damage, and Antioxidant Capacity in a Wild-Living Mammal, the European Badger (Meles meles).

Physiol Biochem Zool 2018 Jul/Aug;91(4):987-1004

Wild-living animals are subject to weather variability that may cause the generation of reactive oxygen species, resulting in oxidative stress and tissue damage, potentially driving demographic responses. Our 3-yr field study investigated the effects of seasonal weather conditions on biomarkers for oxidative stress, oxidative damage, and antioxidant defense in the European badger (Meles meles). We found age class effects: cubs were more susceptible to oxidative stress and oxidative damage than adults, especially very young cubs in the spring, when they also exhibited lower antioxidant biomarkers than adults. Read More

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http://dx.doi.org/10.1086/698609DOI Listing
November 2018
4 Reads

The Influence of Sex, Parasitism, and Ontogeny on the Physiological Response of European Eels (Anguilla anguilla) to an Abiotic Stressor.

Physiol Biochem Zool 2018 Jul/Aug;91(4):976-986

Migration of adult European eels (Anguilla anguilla) from freshwater feeding grounds to oceanic spawning grounds is an energetically demanding process and is accompanied by dramatic physiological and behavioral changes. Humans have altered the aquatic environment (e.g. Read More

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http://dx.doi.org/10.1086/698689DOI Listing
November 2018
5 Reads

Effects of Warm Temperatures on Metabolic Rate and Evaporative Water Loss in Tuatara, a Cool-Climate Rhynchocephalian Survivor.

Physiol Biochem Zool 2018 Jul/Aug;91(4):950-966

The thermal sensitivity of physiological rates is a key characteristic of organisms. For tuatara (Sphenodon punctatus), the last surviving member of the reptilian order Rhynchocephalia and an unusually cold-tolerant reptile, we aimed to clarify responses in indices of metabolic rate (oxygen consumption [[Formula: see text]] and carbon dioxide production [[Formula: see text]]) as well as rates of total evaporative water loss (TEWL) to temperatures at the warmer end of the known tolerated range; currently, patterns for metabolic rate are unclear above 25°C, and TEWL has not been measured above 25°C. We first established that metabolic rate was lowest during the photophase and then measured [Formula: see text], [Formula: see text], and TEWL at six temperatures (12°, 20°, 24°, 27°, 29°, and 30°C) during this phase. Read More

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http://dx.doi.org/10.1086/698495DOI Listing
November 2018
1 Read

Testing for Short- and Long-Term Thermal Plasticity in Corticosterone Responses of an Ectothermic Vertebrate.

Physiol Biochem Zool 2018 Jul/Aug;91(4):967-975

4 School of Science and Health, Hawkesbury campus, Western Sydney University, Locked Bag 1797, Penrith, New South Wales 2751, Australia.

Phenotypic plasticity, broadly defined as the capacity of one genotype to produce more than one phenotype, is a key mechanism for how animals adapt to environmental (including thermal) variation. Vertebrate glucocorticoid hormones exert broad-scale regulation of physiological, behavioral, and morphological traits that influence fitness under many life-history or environmental contexts. Yet the capacity for vertebrates to demonstrate different types of thermal plasticity, including rapid compensation or longer acclimation in glucocorticoid hormone function, when subject to different environmental temperature regimes remains poorly addressed. Read More

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http://dx.doi.org/10.1086/698664DOI Listing
November 2018
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Stress-Induced Hyperglycemia in White-Throated and White-Crowned Sparrows: A New Technique for Rapid Glucose Measurement in the Field.

Physiol Biochem Zool 2018 Jul/Aug;91(4):943-949

Organisms experience stressors, and the physiological response to these stressors is highly conserved. Acute stress activates both the sympathetic nervous system and the hypothalamic-pituitary-adrenal axis, increasing epinephrine, norepinephrine, and glucocorticoids, collectively promoting glucose mobilization. While this is well characterized in mammals, the hyperglycemic response to stress in avian and nonavian reptiles has received less attention. Read More

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http://dx.doi.org/10.1086/698536DOI Listing
November 2018
1 Read

A Comparison of Reproductive and Energetic States in a Marine Apex Predator (the Tiger Shark, Galeocerdo cuvier).

Physiol Biochem Zool 2018 Jul/Aug;91(4):933-942

To fuel the high energetic demands of reproduction, vertebrates employ different tactics of resource use. Large sharks exhibit long gestation periods and have relatively few well-developed young, which likely incurs high energetic costs. However, information on the relationship between the reproductive and energetic states for most shark species is lacking. Read More

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https://www.journals.uchicago.edu/doi/10.1086/698496
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http://dx.doi.org/10.1086/698496DOI Listing
November 2018
4 Reads

Long-Term Trait Consistency in Mice Selected for Swim-Induced High Aerobic Capacity.

Physiol Biochem Zool 2018 Jul/Aug;91(4):925-932. Epub 2018 May 14.

The majority of studies show that metabolic rates are usually repeatable at the individual level, although their repeatabilities tend to decline with time and to be strongly affected by physiological changes. Changes in individual repeatabilities may therefore affect putative differences between experimental groups or populations. This problem is particularly relevant to artificial selection experiments that apply the selection protocol at early life stages, running the risk of a poor correlation of the trait with itself throughout the life cycle of individuals. Read More

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http://dx.doi.org/10.1086/698213DOI Listing
November 2018
2 Reads

Both Low Temperature and Shorter Duration of Food Availability Delay Testicular Regression and Affect the Daily Cycle in Body Temperature in a Songbird.

Authors:
Alistair Dawson

Physiol Biochem Zool 2018 Jul/Aug;91(4):917-924

Photoperiodic control of reproduction in birds is based on two processes, a positive effect leading to gonadal maturation and an inhibitory effect subsequently inducing regression. Nonphotoperiodic cues can modulate photoperiodic control, particularly the inhibitory process. In previous studies of common starlings (Sturnus vulgaris), (1) restriction of food availability to 8 h after dawn had little effect on testicular maturation but dramatically delayed subsequent regression and (2) lower ambient temperature also had little effect during maturation but delayed regression. Read More

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http://dx.doi.org/10.1086/698109DOI Listing
November 2018
1 Read

Maternal Thyroid Hormones: An Unexplored Mechanism Underlying Maternal Effects in an Ecological Framework.

Physiol Biochem Zool 2018 May/Jun;91(3):904-916

Maternal effects are currently acknowledged as important causes of transgenerational phenotypic variation and a potential mechanism to adapt offspring to predicted environments, thus having a pivotal role in ecology and evolution. Research in hormonal mechanism underlying maternal effects has focused heavily on steroid hormones. Other hormones, such as thyroid hormones (THs; thyroxine and triiodothyronine), have been largely ignored in ecological research until recently. Read More

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http://dx.doi.org/10.1086/697380DOI Listing
October 2018
2 Reads

Host Respiration Rate and Injury-Derived Cues Drive Host Preference by an Ectoparasite of Fruit Flies.

Physiol Biochem Zool 2018 May/Jun;91(3):896-903

Host bioenergetics and energy fluxes can be applied to measure the ecological and physiological effects of parasitism. By measuring changes in host metabolic rate, one can estimate the physiological costs of infection. Additionally, metabolic rate dictates the rate of resource conversion within a host and, by extension, the resources available to a parasite. Read More

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http://dx.doi.org/10.1086/697466DOI Listing
October 2018
2 Reads

Seasonal Changes in Metabolism and Cellular Stress Phenomena in the Gilthead Sea Bream (Sparus aurata).

Physiol Biochem Zool 2018 May/Jun;91(3):878-895

Seasonal temperature changes may take organisms to the upper and lower limit of their thermal range, with respective variations in their biochemical and metabolic profile. To elucidate these traits, we investigated metabolic and antioxidant patterns in tissues of sea bream Sparus aurata during seasonal acclimatization for 1 yr in the field. Metabolic patterns were assessed by determining lactate dehydrogenase, citrate synthase, and β-hydroxyacyl CoA dehydrogenase activities, their kinetic properties and plasma levels of glucose, lactate, and triglycerides and tissue succinate levels. Read More

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http://dx.doi.org/10.1086/697170DOI Listing
October 2018
3 Reads

Sex-Specific Associations between Telomere Dynamics and Oxidative Status in Adult and Nestling Pied Flycatchers.

Physiol Biochem Zool 2018 May/Jun;91(3):868-877

Oxidative stress can contribute to an acceleration of telomere erosion, leading to cellular senescence and aging. Increased investment in reproduction is known to accelerate senescence, generally resulting in reduced future reproductive potential and survival. To better understand the role played by oxidative status and telomere dynamics in the conflict between maintenance and reproduction, it is important to determine how these factors are related in parents and their offspring. Read More

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http://dx.doi.org/10.1086/697294DOI Listing
October 2018
4 Reads

Validation of a Pulse Oximetry System for High-Altitude Waterfowl by Examining the Hypoxia Responses of the Andean Goose (Chloephaga melanoptera).

Physiol Biochem Zool 2018 May/Jun;91(3):859-867

Hypoxia at high altitudes constrains O supply to support metabolism, thermoregulation in the cold, and exercise. High-altitude natives that somehow overcome this challenge-who live, reproduce, and sometimes perform impressive feats of exercise at high altitudes-are a powerful group in which to study the evolution of physiological systems underlying hypoxia resistance. Here, we sought to determine whether a common pulse oximetry system for rodents (MouseOx Plus) can be used reliably in studies of high-altitude birds by examining the hypoxia responses of the Andean goose. Read More

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http://dx.doi.org/10.1086/697053DOI Listing
October 2018
5 Reads

Antioxidant Enzyme Activities Vary with Predation Risk and Environmental Conditions in Free-Living Passerine Birds.

Physiol Biochem Zool 2018 May/Jun;91(3):837-848

Prolonged physiological stress response may lead to an excessive production of reactive oxygen species (ROS) and ultimately to oxidative stress and severe fitness costs. We investigated whether natural variation in predation risk, induced by pygmy owls (Glaucidium passerinum), modifies the oxidative status of two free-living food-supplemented passerine bird species-the great tit (Parus major) and the willow tit (Poecile montanus)-in March 2012 and 2013. Predation risk significantly affected antioxidant enzyme activities of willow tits. Read More

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http://dx.doi.org/10.1086/697087DOI Listing
October 2018
4 Reads

Experimental Increases in Foraging Costs Affect Pectoralis Muscle Mass and Myostatin Expression in Female, but Not Male, Zebra Finches (Taeniopygia guttata).

Physiol Biochem Zool 2018 May/Jun;91(3):849-858

Skeletal muscle remodeling is an important component of phenotypic flexibility in birds and impacts organismal metabolism and performance, which could potentially influence fitness. One regulator of skeletal muscle remodeling is myostatin, an autocrine/paracrine muscle growth inhibitor that may be down-regulated under conditions promoting heavier muscle masses. In this study, we employed protocols requiring hovering while foraging to increase foraging costs and modify phenotypes of zebra finches (Taeniopygia guttata). Read More

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http://dx.doi.org/10.1086/697153DOI Listing
October 2018
7 Reads