Oxytocin neurons signal state-dependent transitions from rest to thermogenesis and behavioral arousal in social and non-social settings.

Core body temperature (Tb) is defended within narrow limits through thermoregulatory behaviors like huddling, nesting, and physical activity as well as autonomic responses like brown fat thermogenesis and peripheral vasodilation. While Tb displays regulated fluctuations across different behavioral states and rest/arousal cycles, the neural control of these transitions is poorly understood. Here, we investigate the relationship between oxytocin neurons of the paraventricular hypothalamus (PVN ) and behavioral and autonomic thermoeffector pathways across physiological states in mice.

Influence of enclosure design on the behaviour and welfare of Pogona vitticeps.

Complex or naturalistic enclosures have become increasingly accepted as those best-suited to improve an animal's welfare. However, designing such enclosures can be difficult if little is known about the animal in the wild, and enclosures that aim to replicate natural habitats must still be assessed to ensure their assumed benefits are realized. Therefore, this study examined the behaviour and physiology of captive-bred bearded dragons (Pogona vitticeps) living in naturalistic- and standard-style enclosures.

Dealing with the heat: Assessing heat stress in an Arctic seabird using 3D-printed thermal models.

The Arctic is warming at four times the global average rate and most studies have focused on the indirect (e.g., changes in food web) rather than the direct effects of climate change.

Exaggeration through sexual selection may impact the thermal biology of arthropods.

Sexual selection is often invoked to explain the evolution of extravagant morphologies, such as antlers and horns. While the focus is typically on the process of exaggeration of these traits, the functional impact of exaggeration remains a topic of debate. One aspect that has been largely overlooked is how exaggerated structures might impact thermal biology.

Behavioural evidence of a humidistat: a temperature-compensating mechanism of hydroregulation in spotted salamanders.

The ability to control hydration state is essential for terrestrial species, especially amphibians, which are highly susceptible to dehydration. Here, we examined how temperature (17°C versus 22°C) influenced behavioural hydroregulation in spotted salamanders (Ambystoma maculatum) using a laboratory humidity gradient. Salamanders defended a constant vapour pressure deficit (VPD) between temperatures by targeting higher relative humidity at 22°C than at 17°C, possibly to compensate for increased evaporative demand at warmer temperatures.

Seasonal plasticity in the thermal sensitivity of metabolism but not water loss in a fossorial ectotherm.

Ectotherms from highly seasonal habitats should have enhanced potential for physiological plasticity to cope with climatic variability. However, whether this pattern is applicable to fossorial ectotherms, who are potentially buffered from thermal variability, is still unclear. Here, we evaluated how seasonal acclimation (spring vs.

Revisiting concepts of thermal physiology: understanding negative feedback and set-point in mammals, birds, and lizards.

The thermoregulatory system of homeothermic endotherms operates to attain thermal equilibrium, that is no net loss or gain of heat, where possible, under a thermal challenge, and not to attain a set-point or any other target body temperature. The concept of a set-point in homeothermic temperature regulation has been widely misinterpreted, resulting in such confusion that some thermoregulation specialists have recommended that it be abandoned. But the set-point concept has enjoyed a resurgence in a different domain, lizard microclimate selection.

Costs and benefits of maternal nest choice: Trade-offs between brood survival and thermal stress in bees.

Optimal nest site selection is crucial in animals whose offspring are completely dependent on the shelter of a nest. Parental decisions influencing nest thermal conditions are particularly important because temperature strongly influences juvenile activity, metabolism, growth, developmental rate, survival, and adult body size. In small ectotherms such as bees, maternal decisions to nest in sun-exposed or shady sites can lead to marked differences in thermal microenvironments inside nests.

Ups and downs of fossorial life: migration restlessness and geotaxis may explain overwintering emergence in the spotted salamander.

To decide whether to remain underground or to emerge from overwintering, fossorial ectotherms simultaneously process environmental, gravitational and circannual migratory cues. Here, we provide an experimental framework to study the behaviour of fossorial ectotherms during soil temperature inversion - a phenomenon that marks the transition between winter and spring - based on three non-mutually exclusive hypotheses (thermoregulation, negative geotaxis and migration restlessness). Using a vertical thermal gradient, we evaluated how temperature selection (Tsel), activity and vertical position selection differed under simulated soil temperature inversion (contrasting the active versus overwintering thermal gradients) in the spotted salamander (Ambystoma maculatum).

Seasonal variation of behavioural thermoregulation in a fossorial salamander ().

Temperature seasonality plays a pivotal role in shaping the thermal biology of ectotherms. However, we still have a limited understanding of how ectotherms maintain thermal balance in the face of varying temperatures, especially in fossorial species. Due to thermal buffering underground, thermal ecology theory predicts relaxed selection pressure over thermoregulation in fossorial ectotherms.

Birds are better at regulating heat loss through their legs than their bills: implications for body shape evolution in response to climate.

Endotherms use their appendages-such as legs, tails, ears and bills-for thermoregulation by controlling blood flow to near-surface blood vessels, conserving heat when it is cold, and dissipating heat in hot conditions. Larger appendages allow greater heat dissipation, and appendage sizes vary latitudinally according to Allen's rule. However, little is known about the relative importance of different appendages for thermoregulation.

Hot crabs with bold choices: Temperature has little impact on behavioural repeatability in Caribbean hermit crabs.

An animal's boldness is generally considered to be influenced by genetic and developmental factors. However, abiotic factors such as temperature have profound effects on the physiology of ectothermic animals, and thus can influence the expression and measurement of this behavioural trait. We examined the relationship between temperature and behaviour in the Caribbean hermit crab (Coenobita clypeatus) using field and lab experiments.

Free-living Allen's hummingbirds (Selasphorus sasin) rarely use torpor while nesting.

For reproducing animals, maintaining energy balance despite thermoregulatory challenges is important for surviving and successfully raising offspring. This is especially apparent in small endotherms that exhibit high mass-specific metabolic rates and live in unpredictable environments. Many of these animals use torpor, substantially reducing their metabolic rate and often body temperature to cope with high energetic demands during non-foraging periods.

Energetic costs of bill heat exchange demonstrate contributions to thermoregulation at high temperatures in toco toucans (Ramphastos toco).

Body temperature regulation under changes in ambient temperature involves adjustments in heat production and heat exchange rates between the animal and the environment. One mechanism involves the modulation of the surface temperature of specific areas of the body through vasomotor adjustment. In homeotherms, this thermoregulatory adjustment is essential for the maintenance of body temperature over a moderate temperature range, known as the thermal neutral zone (TNZ).

Thermoconforming rays of the star-nosed mole.

The star-nosed mole (Condylura cristata) is renowned for its densely innervated 22 appendage star-like rostrum ('star') specialized for tactile sensation. As a northerly distributed insectivorous mammal exploiting aquatic and terrestrial habitats, these vascularized nasal rays are regularly exposed to cold water and thermally conductive soil, leading us to ask whether the star surface temperature, a proxy for blood flow, conforms to the local ambient temperature to conserve body heat. Alternatively, given the exquisite sensory nature of the star, we posited that the uninsulated rays may be kept warm when foraging to maintain high mechanosensory function.

Use of crowdsourced images for determining 2D:4D and relationship to pro-environmental variables.

Unlabelled: The primary purpose of this study was to examine whether 2D:4D ratios (a putative measure of prenatal androgen exposure) could be determined using participant-submitted hand images. The secondary purpose was to examine whether 2D:4D ratio was associated with pro-environmental behaviors, attitudes, and empathy, given the recent literature linking sex to environmental attitudes and actions. Participants ( = 1065) were asked via an online survey to submit a clear photograph of their right hand, palm side up.

Thermal adaptation best explains Bergmann's and Allen's Rules across ecologically diverse shorebirds.

Bergmann's and Allen's rules state that endotherms should be larger and have shorter appendages in cooler climates. However, the drivers of these rules are not clear. Both rules could be explained by adaptation for improved thermoregulation, including plastic responses to temperature in early life.

Vocalization-associated respiration patterns: thermography-based monitoring and detection of preparation for calling.

Vocal emission requires coordination with the respiratory system. Monitoring the increase in laryngeal pressure, which is needed for vocal production, allows detection of transitions from quiet respiration to vocalization-supporting respiration. Characterization of these transitions could be used to identify preparation for vocal emission and to examine the probability of it manifesting into an actual vocal production event.

Changes in Body Surface Temperature Play an Underappreciated Role in the Avian Immune Response.

AbstractFever and hypothermia are well-characterized components of systemic inflammation. However, our knowledge of the mechanisms underlying such changes in body temperature is largely limited to rodent models and other mammalian species. In mammals, high dosages of an inflammatory agent (e.

Naked mole-rat brown fat thermogenesis is diminished during hypoxia through a rapid decrease in UCP1.

Naked mole-rats are among the most hypoxia-tolerant mammals. During hypoxia, their body temperature (T) decreases via unknown mechanisms to conserve energy. In small mammals, non-shivering thermogenesis in brown adipose tissue (BAT) is critical to T regulation; therefore, we hypothesize that hypoxia decreases naked mole-rat BAT thermogenesis.

Climate-associated decline of body condition in a fossorial salamander.

Temperate ectotherms have responded to recent environmental change, likely due to the direct and indirect effects of temperature on key life cycle events. Yet, a substantial number of ectotherms are fossorial, spending the vast majority of their lives in subterranean microhabitats that are assumed to be buffered against environmental change. Here, we examine whether seasonal climatic conditions influence body condition (a measure of general health and vigor), reproductive output, and breeding phenology in a northern population of fossorial salamander (Spotted Salamander, Ambystoma maculatum).