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Field Metabolic Rate (field + metabolic_rate)
Selected AbstractsField metabolic rates of black-browed albatrosses Thalassarche melanophrys during the incubation stageJOURNAL OF AVIAN BIOLOGY, Issue 6 2004Scott A. Shaffer Field metabolic rates (FMR) and activity patterns of black-browed albatrosses Thalassarche melanophrys were measured while at sea and on nest during the incubation stage at Kerguelen Island, southwestern Indian Ocean. Activity-specific metabolic rates of five albatrosses at sea (FMRat-sea) were measured using doubly labeled water (DLW), and by equipping birds with wet-dry activity data loggers that determined when birds were in flight or on the water. The metabolic rates of four birds incubating their eggs (FMRon-nest) were also measured using DLW. The mean±SD FMRat-sea of albatrosses was 611±96 kJ kg,1 d,1 compared to FMRon-nest of 196±52 kJ kg,1 d,1. While at sea, albatrosses spent 52.9±8.2% (N=3) of their time in flight and they landed on the water 41.2±13.9 times per day. The FMR of black-browed albatrosses appear to be intermediate to that of three other albatross species. Based on at-sea activity, the power requirement of flight was estimated to be 8.7 W kg,1 (or 4.0×predicted BMR), which is high compared to other albatross species, but may be explained by the high activity levels of the birds when at sea. The FMRat-sea of albatrosses, when scaled with body mass, are lower than other seabirds of similar body size, which probably reflects the economical nature of their soaring flight. [source] Seasonal field metabolic rate and dietary intake in Arabian Babblers (Turdoides squamiceps) inhabiting extreme desertsFUNCTIONAL ECOLOGY, Issue 5 2000A. Anava Abstract 1.,Arabian Babblers (Turdoides squamiceps Cretzsch.; mean adult body mass = 72·5 g) inhabit extreme deserts of Israel. They consume invertebrates and fruits and, at least at our study site, do not drink. It was hypothesized that babblers (1) in general, use relatively less energy and water than other birds of its body mass; and (2) consume a more water-rich diet (mainly fruits) in summer and more energy-rich diet (mainly invertebrates) in winter. Doubly labelled water was used to determine seasonal field metabolic rate (FMR) and water influx rate (WIR) and to estimate dietary selection in free-living Arabian Babblers. 2.,Babblers in winter weighed significantly more than in summer, and males weighed more than females in both seasons. Tritiated water (TOH) space, as a proportion of body mass, was higher in males than in females in summer but no difference between sexes was found in winter. Males in summer had a higher TOH space, proportionally, than males in winter but there was no difference between seasons in females. Mass-specific WIR did not differ between sexes in any season and averaged 0·475 ml g,1 d,1 in winter which was significantly higher than the 0·283 ml g,1 d,1 in summer. 3.,The mean daily energy expenditure of the babblers did not differ either between seasons or between sexes within seasons and averaged 1·61 kJ g,1 d,1 in winter and 1·68 kJ g,1 d,1 in summer. It was calculated that each babbler consumed an average of 5·09 g dry matter invertebrates and 1·83 g dry matter fruits in summer (for a 68·2-g bird; mean adult body mass in summer) and 3·49 g dry matter invertebrates and 6·61 g dry matter fruits in winter (for a 76·9-g bird; mean adult body mass in winter). 4.,When compared with other avian species, FMR and WIR of babblers were lower than bird species in general, but were similar to those of other desert birds. It was calculated that proportional dietary intake, on a dry matter basis, included 0·79 insects and 0·21 fruits in summer and 0·35 insects and 0·65 fruits in winter. Therefore, the babblers consumed a relatively energy-rich diet in summer and water-rich diet in winter which refuted our hypothesis. Most of the metabolizable energy was provided by invertebrates in both seasons; invertebrates provided more water in summer but fruits provided more in winter. [source] Daily energy expenditure of singing great reed warblers Acrocephalus arundinaceusJOURNAL OF AVIAN BIOLOGY, Issue 4 2008Dennis Hasselquist According to honest signalling theory, signals must be costly to produce to retain information about the signaller's quality. The song produced by male birds during breeding is a vocal "ornament" used for intra- and inter-sexual purposes. The energetic cost of this vocal signal remains a contentious issue. We used the doubly labelled water method to measure field metabolic rate by estimating CO2 production and then convert this to daily energy expenditure (DEE) in great reed warbler males singing under natural conditions (10 at low to moderate intensity and 7 at very high intensity from dawn to dusk). There was a significant positive relationship between singing intensity and DEE. From this relationship we extrapolated the average DEE for intensely singing males (i.e., males producing song sounds 50% of the time and hence sitting at their elevated song post in the top of a reed stem more or less continuously throughout the ,20 h of daylight) to 3.3×BMR (basal metabolic rate) and for non-singing males to 2.2×BMR. The mean DEE measured for the seven males singing with very high intensity was 3.1×BMR. The maximum measured DEE for a single male was 3.9×BMR, i.e. close to the maximum sustainable DEE (4×BMR), and the minimum DEE was 2.1×BMR for a male singing at very low intensity. These results imply that producing intensive advertising song in birds may incur a substantial cost in terms of increased energy expenditure. [source] Relative longevity and field metabolic rate in birdsJOURNAL OF EVOLUTIONARY BIOLOGY, Issue 5 2008A. P. MŘLLER Abstract Metabolism is a defining feature of all living organisms, with the metabolic process resulting in the production of free radicals that can cause permanent damage to DNA and other molecules. Surprisingly, birds, bats and other organisms with high metabolic rates have some of the slowest rates of senescence begging the question whether species with high metabolic rates also have evolved mechanisms to cope with damage induced by metabolism. To test whether species with the highest metabolic rates also lived the longest I determined the relationship between relative longevity (maximum lifespan), after adjusting for annual adult survival rate, body mass and sampling effort, and mass-specific field metabolic rate (FMR) in 35 species of birds. There was a strongly positive relationship between relative longevity and FMR, consistent with the hypothesis. This conclusion was robust to statistical control for effects of potentially confounding variables such as age at first reproduction, latitude and migration distance, and similarity in phenotype among species because of common phylogenetic descent. Therefore, species of birds with high metabolic rates senesce more slowly than species with low metabolic rates. [source] Biochemical universality of living matter and its metabolic implicationsFUNCTIONAL ECOLOGY, Issue 4 2005A. M. MAKARIEVA Summary 1Recent discussions of metabolic scaling laws focus on the model of West, Brown & Enquist (WBE). The core assumptions of the WBE model are the size-invariance of terminal units at which energy is consumed by living matter and the size-invariance of the rate of energy supply to these units. Both assumptions are direct consequences of the biochemical universality of living matter. However, the second assumption contradicts the central prediction of the WBE model that mass-specific metabolic rate q should decrease with body mass with a scaling exponent µ = ,1/4, thus making the model logically inconsistent. 2Examination of evidence interpreted by WBE and colleagues in favour of a universal µ = ,1/4 across 15 and more orders of magnitude range in body mass reveals that this value resulted from methodological errors in data assortment and analysis. 3Instead, the available evidence is shown to be consistent with the existence of a size-independent mean value of mass-specific metabolic rate common to most taxa. Plotted together, q -values of non-growing unicells, insects and mammals in the basal state yield µ , 0. Estimated field metabolic rates of bacteria and vertebrates are also size-independent. 4Standard mass-specific metabolic rates of most unicells, insects and mammals studied are confined between 1 and 10 W kg,1. Plant leaves respire at similar rates. This suggests the existence of a metabolic optimum for living matter. With growing body size and diminishing surface-to-volume ratio organisms have to change their physiology and perfect their distribution networks to keep their q in the vicinity of the optimum. [source] | ||||||||||