Glucocorticoid steroids modulate immunocompetence in complex ways with both immunoenhancing and immunosuppressive effects vertebrates exposed to different stressors. Such bimodal have been associated variation duration intensity of the stress response. Given that natural populations a multitude stressors, better understanding functional association between response, resulting changes glucocorticoid plasma levels their impact on aspects emerges as cornerstone for vertebrate conservation...

The hypothalamic‐pituitary‐adrenal (HPA) axis is important in regulating energy metabolism and mediating responses to stressors, including increasing availability during physical exercise. In addition, glucocorticoids act directly on the central nervous system influence behavior, locomotor activity. To explore potential changes HPA as animals evolve higher voluntary activity levels, we characterized plasma corticosterone (CORT) concentrations adrenal mass four replicate lines of house mice...

Abstract We investigated the evolution of anuran locomotor performance and its morphological correlates as a function habitat use lifestyles. reanalysed subset data reported by Zug ( Smithson. Contrib. Zool. 1978; 276: 1–31) employing phylogenetically explicit statistical methods n = 56 species), assembled on ratio between hind‐limb length snout‐vent (SVL) from literature museum specimens for large subgroup species original paper 43 species). Analyses using independent contrasts revealed...

Abstract The relationships between morphology, performance, behavior and ecology provide evidence for multiple complex phenotypic adaptations. anuran body plan, example, is evolutionarily conserved shows clear specializations to jumping performance back at least the early Jurassic. However, there are instances of more recent adaptation habit diversity in post‐cranial skeleton, including relative limb length. present study tested adaptive models morphological evolution anurans associated with...

The energetics of terrestrial locomotion are considerable interest to ecologists and physiologists, but nearly all our current knowledge comes from animals undergoing forced exercise. To explore patterns energy use behavior during voluntary exercise, we developed methods allowing continuous measurements metabolic rates in freely behaving small mammals, with high temporal resolution over periods several days. We used this approach examine relationships between ambient temperature (Ta),...

Selective breeding for high wheel-running activity has generated four lines of laboratory house mice (S lines) that run about 170% more than their control counterparts (C on a daily basis, mostly because they faster. We tested whether maximum aerobic metabolic rates (V(O2max)) have evolved in concert with wheel-running, using 48 females from generation 35. Voluntary and were measured days 5+6 wheel access (mimicking conditions during selection), wheels enclosed chambers. Following this,...

Selective breeding for over 35 generations has led to four replicate (S) lines of laboratory house mice (Mus domesticus) that run voluntarily on wheels about 170% more than random‐bred control (C) lines. We tested whether S have evolved higher running performance by increasing economy (i.e., decreasing energy spent per unit distance) as a correlated response selection, using recently developed method allows nearly continuous measurements oxygen consumption (V̇o2) and speed in freely behaving...

We studied relations between maximal O2 consumption (VO2 max) during forced exercise and subordinate traits associated with blood transport cellular respiration in four lines of mice selectively bred for high voluntary wheel running (S lines) their nonselected control (C) lines. Previously, we reported VO2 max 59 females at three Po2 (hypoxia = 14% O2, normoxia 21%, hyperoxia 30%). Here, test the hypothesis that variation can be explained, part, by hemoglobin concentration necessary to...

Locomotion is central to behavior and intrinsic many fitness-critical activities (e.g., migration, foraging), it competes with other life-history components for energy. However, detailed analyses of how changes in locomotor activity running affect energy budgets are scarce. We quantified these effects four replicate lines house mice that have been selectively bred high voluntary wheel (S lines) their nonselected control (C lines). monitored speeds oxygen consumption 24-48 h determine daily...

The viability and interpretation of techniques for the evaluation immunocompetence animals in their natural environment has been largely debated. One these methods is based on testing antimicrobial capacity blood and/or plasma vitro, which could rapidly effectively assess immunological conditions populations. We tested applicability (ACP) assay anuran amphibians from Atlantic Forest. was performed by measuring both turbidity (in a spectrophotometer) colony forming units (CFU) remaining...

Stressful experiences can promote harmful effects on physiology and fitness. However, stress-mediated hormonal immune changes are complex may be highly dependent body condition. Here, we investigated captivity-associated stress effects, over 7, 30, 60, 90 days plasma corticosterone (CORT) testosterone (T) levels, index, innate immunity (bacterial killing ability phagocytosis of peritoneal cells) in toads (Rhinella icterica). Toads captivity exhibited elevated CORT decreased T immunity,...

The Araguaia River dolphin is endemic to the Tocantins-Araguaia Basin and under severe anthropogenic threats. Given species’ vulnerability historical neglect, preliminary data on its health physical parameters are presented, along with an evaluation of potential differences between individuals from areas varying human activity. A comparison these closely related species, Amazon I. geoffrensis , was also aimed. Twenty-four dolphins were captured released in Cantão State Park (protected area,...

We compared maximum aerobic capacity during forced exercise (VO2max) in hypoxia (PO2=14% O2), normoxia (21%) and hyperoxia (30%) of lines house mice selectively bred for high voluntary wheel running (S lines) with their four unselected control (C) lines. also tested pleiotropic effects the ;mighty mini-muscle' allele, a Mendelian recessive that causes 50% reduction hind limb muscle but doubling mass-specific enzyme activity, among other effects. VO2max female was measured on motorized...

The possible trade-off between the roles of glucocorticoids as facilitators energy substrate mobilization and neural inhibitors sexual behavior during breeding season is under debate. We studied relationship calling territorial with plasma levels corticosterone (CORT) testosterone (T) across Hypsiboas faber, a large Neotropical treefrog. investigated these relationships through focal observations males naturally, followed by blood sampling for hormonal radioimmunoassay. additionally used an...

Abstract Previous studies in a variety of vertebrates show stressed animals to exhibit acute increases glucocorticoid levels, with consequences for immune modulation. Chronically elevated levels are mostly associated immunosuppression. However, there is still paucity knowledge regarding the amphibian physiological reaction short‐ and long‐term stress conditions, including effects on response. In order better clarify relationship between glucocorticoids response, newly captured Brazilian...

Amphibian species richness increases toward the equator, particularly in humid tropical forests. This relation between amphibian and environmental water availability has been proposed to be a consequence of their high rates evaporative loss. In this way, traits that estimate balance are expected covary with climate constrain species' geographic distribution. Furthermore, we predicted coexisting anurans would have adapted local hydric conditions. We compared describe 17 occur mesic Atlantic...

Stressors can increase plasma glucocorticoid (GC) levels and decrease androgen in different species of vertebrates. GCs have immune-enhancing or immunosuppressive effects, which are dependent upon stress duration intensity. The worldwide decline amphibian populations is strongly linked to an array stressors. impacts on GCs, androgens, the immune response important clarify should lead better development conservation strategies. present study adult male toads Rhinella schneideri investigated...

Immune activity is temperature-dependent and strongly related to thermal biology in ectotherms. Eurythermic, vs stenothermic, species commonly show a broader range of immune responses. Furthermore, the development behavioral fever ectotherms correlated with improved function. Although amphibians generally restricted capacity for thermoregulation field, has been documented laboratory several anurans. However, match between response at preferendum still be determined these animals. In this...

Immune responses have been mostly studied at a specific time in anuran species. However, time-changes related to immunomodulation associated with glucocorticoid (GC) alterations following stressors and GC treatment are complex. The present study describes time-related changes immune response corticosterone (CORT) plasma levels restraint challenge, short, mid long-term captivity, CORT exogenous administration by transdermal application (TA) Rhinella ornata toads. We observed increased...

SUMMARY To examine the evolution of endurance-exercise behaviour, we have selectively bred four replicate lines laboratory mice (Mus domesticus) for high voluntary wheel running (`high runner' or HR lines),while also maintaining non-selected control (C) lines. By generation 16,HR ran ∼2.7-fold more than C mice, mainly by faster(especially in females), a differential maintained through subsequent generations, suggesting an evolutionary limit unknown origin. We hypothesized that would higher...