Ecological consequences of temperature regulation: Why might the mountain pygmy possum Burramys parvus need to hibernate near underground streams?

Hibernating female big brown bats (Eptesicus fuscus) adjust huddling and drinking behaviour, but not arousal frequency, in response to low humidity

Many mammals hibernate during winter, reducing energy expenditure via bouts of torpor. The majority of a hibernator's energy reserves are used to fuel brief, but costly, arousals from torpor. Although arousals likely serve multiple functions, an important one is to restore water stores depleted during torpor. Many hibernating bat species require high humidity, presumably to reduce torpid water loss, but big brown bats (Eptesicus fuscus) appear tolerant of a wide humidity range. We tested the hypothesis that hibernating female E. fuscus use behavioural flexibility during torpor and arousals to maintain water balance and reduce energy expenditure. We predicted: (1) E. fuscus hibernating in dry conditions would exhibit more compact huddles during torpor and drink more frequently than bats in high humidity conditions; and (2) the frequency and duration of torpor bouts and arousals, and thus total loss of body mass would not differ between bats in the two environments. We housed hibernating E. fuscus in temperature- and humidity-controlled incubators at 50% or 98% relative humidity (8°C, 110 days). Bats in the dry environment maintained a more compact huddle during torpor and drank more frequently during arousals. Bats in the two environments had a similar number of arousals, but arousal duration was shorter in the dry environment. However, total loss of body mass over hibernation did not differ between treatments, indicating that the two groups used similar amounts of energy. Our results suggest that behavioural flexibility allows hibernating E. fuscus to maintain water balance and reduce energy costs across a wide range of hibernation humidities.

Protecting western redcedar from deer browsing-with a passing reference to TRP channels

This editorial is about tree farming. It proposes to test in an experiment whether co-planting (in the same hole) western redcedar (WRC, Thuja plicata) with Sitka spruce (Picea sitchensis) protects WRC seedlings from wildlife browsing. This sustainable protection method is an alternative to the traditional use of mechanical devices and big-game repellents. Many repellents contain transient receptor potential (TRP) agonists, such as capsaicin, a TRP vanilloid-1 agonist. This editorial also delivers a puzzle: while herbivores avoid capsaicin, why do people living in hot climates consume large quantities of it (in chili peppers)?

Thermal physiology in a changing thermal world

This editorial focuses on articles submitted to the Temperature call "Thermal Physiology in a Changing Thermal World." It highlights an array of topics related to thermoregulatory and metabolic functions in adverse environments, and the complexity and adaptability of the systems to changing climatic conditions, at various levels of body organization.

Conservation physiology: A new challenge for thermal biologists

Global change presents a huge and exciting challenge to the study of thermal physiology. The implication of thermoregulatory strategies and abilities for the survival of individuals and species, are of high importance for predicting species response to global change challenges and ways to mitigate them, and for conservation acts. A good example of such a study is the paper by Cooper and Withers in this issue.¹