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Metabolic rate is a key aspect of organismal biology and the identification of selective factors that have led to species differences is a major goal of evolutionary physiology. We tested whether environmental characteristics and/or diet were significant predictors of interspecific variation in rodent metabolic rates. Mass-specific basal metabolic rates(More)
Through functional analyses, integrative physiology is able to link molecular biology with ecology as well as evolutionary biology and is thereby expected to provide access to the evolution of molecular, cellular, and organismic functions; the genetic basis of adaptability; and the shaping of ecological patterns. This paper compiles several exemplary(More)
We analyzed and compared the scaling of both basal and maximal thermogenic metabolic rates in passerine and nonpasserine birds using conventional and phylogenetic methods. In spite of the presumed adaptive importance of both metabolic traits, few studies concerning both their relationships and their ecological and evolutionary constraints have been(More)
It is generally accepted that human Alzheimer's disease (AD) neuropathology markers are completely absent in rodent brains. We report here that an aged wild-type South American rodent, Octodon degu, expresses neuronal beta-amyloid precursor protein (beta-APP695) displaying both intracellular and extracellular deposits of amyloid-beta-peptide (Abeta),(More)
As a first examination of the additive genetic variance of thermoregulatory traits in a natural population of endotherms, we studied the quantitative genetics of key physiological ecology traits in the leaf-eared mouse, Phyllotis darwini. We measured basal metabolic rate (BMR), nonshivering thermogenesis (NST), maximum metabolic rate for thermoregulation(More)
Global climate change is one of the greatest threats to biodiversity; one of the most important effects is the increase in the mean earth surface temperature. However, another but poorly studied main characteristic of global change appears to be an increase in temperature variability. Most of the current analyses of global change have focused on mean(More)
PURPOSE To determine the eye's spectral sensitivity in three species of the genus Octodon (order Rodentia; infraorder Caviomorpha), O. degus, O. bridgesi, and O. lunatus, as well as the spectral properties of the animals' fur and urine and of objects in their habitat. The genus is endemic in Chile and contains species with different habitats and circadian(More)
Subterranean mammals are generally considered to have reduced eyes and apparent blindness as a convergent adaptation to their lightless microhabitat. However, there are substantial interspecific differences. We have studied the prospect of vision in the Chilean subterranean rodent cururo (Spalacopus cyanus, Octodontidae) by analyzing the optical properties(More)
We studied the photopic spectral sensitivity in the green-backed firecrown, Sephanoides sephaniodes, a South American hummingbird, and its possible ecological relationship with preferred flowers and body colouration. Avian colour vision is in general tetrachromatic with at least four types of cones, which vary in sensitivity from the near ultraviolet (UV)(More)
Huddling in small mammals appears as an efficient response to low ambient temperatures with important consequences in thermoregulatory energy savings. These energy savings have been ascribed to a decrease in the exposed area in relation to the animal's volume. It has been proposed that during huddling reductions in the exposed area and in the metabolic rate(More)