scholarly journals Comparative physiology of five tropical montane songbirds reveals differential seasonal acclimatisation and cold adaption

2020 ◽  
Author(s):  
Samuel E.I. Jones ◽  
Martin Suanjak ◽  
Joseph A. Tobias ◽  
Robin Freeman ◽  
Steven J. Portugal
Keyword(s):  
Cold Tolerance ◽  
Body Mass ◽  
Physiological Traits ◽  
Metabolic Rates ◽  
Comparative Physiology ◽  
Local Climate ◽  
Open Flow ◽  
Cold Adaption ◽  
Seasonal Regulation ◽  
Seasonal Shifts

AbstractThe physiology of tropical birds is poorly understood, particularly in how it relates to local climate and changes between seasons. This is particularly true of tropical montane species, which may have sensitive thermal tolerances to local microclimates. We studied metabolic rates (using open flow respirometry), body mass and haemoglobin concentrations of five sedentary Mesoamerican songbirds between the summer and winter at two elevations (1550 m and 1950 m, respectively). We asked whether there were uniform seasonal shifts in physiological traits across species, and whether higher elevation species displayed evidence for cold tolerance. Seasonal shifts in metabolic rates differed between the three species for which data were collected. Basal metabolic rates in one species – black-headed nightingalethrushes Catharus mexicanus – were up-regulated in summer (~19% increase of winter metabolism), however two other species displayed no seasonal regulation. No species exhibited shifts in haemoglobin concentrations across season or across elevation, whereas body mass in two species was significantly higher in the summer. One species restricted to higher elevations – ruddy-capped nightingale-thrushes C. frantzii – displayed physiological traits indicative of cold-tolerance. Although only summer data were available for this species (C. frantzii), metabolic rates were constant across temperatures tested (5-34°C) and haemoglobin concentrations were significantly higher compared to the other four species. Our results suggest that seasonal acclimatisation in physiological traits is variable between species and appear unrelated to changes in local climate. As such, the distinct physiological traits observed in ruddy-capped nightingale-thrushes likely relate to historic isolation and conserved physiological traits rather than contemporary climatic adaption.

Do season and distribution affect thermal energetics of a hibernating bat endemic to the tropics and subtropics?

2011 ◽  
Vol 301 (2) ◽  
pp. R542-R547 ◽  
Author(s):  
Clare Stawski ◽  
Fritz Geiser
Keyword(s):  
Body Temperature ◽  
Body Mass ◽  
Basal Metabolic Rate ◽  
Seasonal Changes ◽  
Metabolic Rates ◽  
Open Flow ◽  
Thermoneutral Zone ◽  
In The Wild ◽  
Thermal Energetics ◽  
The Tropics

Although many tropical and subtropical areas experience pronounced seasonal changes in weather and food availability, few studies have examined and none have compared the thermal physiology and energetics of a hibernating mammal that is restricted to these regions. We quantified thermal energetics of northern long-eared bats ( Nyctophilus bifax; body mass ∼10 g) during summer, winter, and spring from a subtropical habitat, and also during winter from a tropical habitat, to determine how N. bifax cope with climate and seasonal changes in weather. We captured bats in the wild and measured metabolic rates via open-flow respirometry. The basal metabolic rate of subtropical bats at an ambient temperature (Ta) of 32.6 ± 0.7°C was 1.28 ± 0.06 ml O2·g−1·h−1 during both summer and winter, similar to other species of Nyctophilus. Resting metabolic rates below the thermoneutral zone increased similarly with decreasing Ta during all seasons and in both regions. All individuals showed a high proclivity to enter torpor at Ta values below the thermoneutral zone. Metabolic rates in torpid thermoconforming bats fell with Ta and body temperature, and mean minimum metabolic rates during torpor were similar during all seasons and in both regions and as predicted from body mass in temperate zone hibernators. At very low Ta, torpid N. bifax thermoregulated, and this threshold Ta differed significantly between subtropical (Ta = 3.5 ± 0.3°C) and tropical (Ta = 6.7 ± 0.7°C) individuals, but not between seasons. Our data show that thermal energetics of N. bifax do not vary seasonally and in many aspects are similar in tropical and subtropical bats; however, torpid individuals from the subtropics allow body temperature to fall to significantly lower values than those from the tropics.

scholarly journals Seasonal Shifts in Cold Tolerance and the Composition of the Gut Microbiome of Dendroctonus valens LeConte Occur Concurrently

Forests ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 888
Author(s):  
Zehai Hou ◽  
Yaxin Dong ◽  
Fengming Shi ◽  
Yabei Xu ◽  
Sixun Ge ◽  
...  
Keyword(s):  
Antioxidant Enzyme ◽  
Cold Tolerance ◽  
Gut Microbiome ◽  
Antioxidant Enzyme Activities ◽  
Severe Damage ◽  
Geographic Ranges ◽  
Dendroctonus Valens ◽  
Different Seasons ◽  
The Relationship ◽  
Seasonal Shifts

Dendroctonus valens LeConte, an invasive bark beetle, has caused severe damage in pine forests and has the potential to disperse into new geographic ranges in China. Although the gut microbiota of D. valens and its fundamental role in host fitness have been investigated widely, little is known about the relationship between the seasonal shifts of both cold tolerance and the gut microbiome of D. valens during overwintering, which occurs at the larval stage. In this study, to examine seasonal variations in the composition of the microbiome, we collected D. valens larvae in September (autumn), January (winter), and May (spring), and then analyzed the bacterial and fungal communities of the gut via sequencing of partial 16S rRNA and ITS genes. In addition, changes in the supercooling capacity and antioxidant enzyme activities of D. valens larvae collected in the different seasons were evaluated. Overwintering resulted in changes to microbial communities. In particular, the abundances of Enterobacter, Serratia, Erwinia, and Klebsiella decreased during overwintering. Concurrent with these changes, the cold tolerance of D. valens larvae was enhanced during overwintering, and the activities of the antioxidant enzymes catalase and peroxidase were reduced. We hypothesize that seasonal shifts in the gut microbiome may be connected to changes in cold tolerance and antioxidant enzyme activity in D. valens. It will be worthwhile to confirm whether seasonal changes in the microbiome contribute to the success of host overwintering.

Body mass and sex, not local climate, drive differences in chill coma recovery times in common garden reared bumble bees

2021 ◽  
Author(s):  
K. Jeannet Oyen ◽  
Laura E. Jardine ◽  
Zachary M. Parsons ◽  
James D. Herndon ◽  
James P. Strange ◽  
...  
Keyword(s):  
Body Mass ◽  
Common Garden ◽  
Bumble Bees ◽  
Local Climate ◽  
Chill Coma ◽  
Recovery Times

scholarly journals Social Group Size and Shelter Availability Influence Individual Metabolic Traits in a Social Fish

2021 ◽  
Author(s):  
Emmanuelle Chrétien ◽  
Daniel Boisclair ◽  
Steven J Cooke ◽  
Shaun S Killen
Keyword(s):  
Metabolic Rate ◽  
Group Size ◽  
Social Group ◽  
Physiological Traits ◽  
Metabolic Rates ◽  
Night Time ◽  
The Social ◽  
Before And After ◽  
Social Treatment ◽  
Shelter Availability

Abstract Group living is widespread among animal species and yields both costs and benefits. Presence of conspecifics can restrict or enhance the expression of individual behaviour, and the recent social environment is thought to affect behavioural responses in later contexts, even when individuals are alone. However, little is known about how social group size influences the expression of individual physiological traits, including metabolic rates. There is some evidence that shoaling can reduce fish metabolic rates but this variable may be affected by habitat conditions such as shelter availability via density-dependent processes. We investigated how social group size and shelter availability influence Eurasian minnow Phoxinus phoxinus metabolic rates estimated by respirometry. Respirometry trials were conducted on fish in isolation before and after they were housed for three weeks in a social treatment consisting in a specific group size (n = 4 or 8) and shelter availability (presence or absence of plant shelter in the experimental tank). Plant shelter was placed over respirometers for half of the duration of the respirometry trials, allowing estimation of minimum day-time and night-time metabolic rates in both conditions (in the presence or absence of plant shelter). Standard metabolic rate (SMR), maximum metabolic rate (MMR), and aerobic scope (AS) were also estimated over the entire trial. Minimum day-time and night-time metabolic rates estimated while in presence of plant shelter were lower than when estimated in absence of plant shelter, both before and after individuals were housed in their social treatment. After the social treatment, SMR were higher for fish that were held in groups of four as compared to that of fish held in groups of eight while MMR showed no difference. Plant shelter availability during the social treatments did not influence SMR or MMR. Our results suggest that social group size may directly influence energy demands of individuals, highlighting the importance of understanding the role of group size on variations in physiological traits associated with energy expenditure.

scholarly journals Subtropical mouse-tailed bats use geothermally heated caves for winter hibernation

2015 ◽  
Vol 282 (1804) ◽  
pp. 20142781 ◽  
Author(s):  
Eran Levin ◽  
Brit Plotnik ◽  
Eran Amichai ◽  
Luzie J. Braulke ◽  
Shmulik Landau ◽  
...  
Keyword(s):  
High Temperature ◽  
Skin Temperature ◽  
Metabolic Rates ◽  
Evaporative Water ◽  
Open Flow ◽  
Ambient Temperatures ◽  
Northern Edge ◽  
Average Skin ◽  
World Distribution ◽  
Winter Hibernation

We report that two species of mouse-tailed bats ( Rhinopoma microphyllum and R. cystops ) hibernate for five months during winter in geothermally heated caves with stable high temperature (20°C). While hibernating, these bats do not feed or drink, even on warm nights when other bat species are active. We used thermo-sensitive transmitters to measure the bats’ skin temperature in the natural hibernacula and open flow respirometry to measure torpid metabolic rate at different ambient temperatures ( T a , 16–35°C) and evaporative water loss (EWL) in the laboratory. Bats average skin temperature at the natural hibernacula was 21.7 ± 0.8°C, and no arousals were recorded. Both species reached the lowest metabolic rates around natural hibernacula temperatures (20°C, average of 0.14 ± 0.01 and 0.16 ± 0.04 ml O 2 g −1 h −1 for R. microphyllum and R. cystops , respectively) and aroused from torpor when T a fell below 16°C. During torpor the bats performed long apnoeas (14 ± 1.6 and 16 ± 1.5 min, respectively) and had a very low EWL. We hypothesize that the particular diet of these bats is an adaptation to hibernation at high temperatures and that caves featuring high temperature and humidity during winter enable these species to survive this season on the northern edge of their world distribution.

The effect of Holocene temperature fluctuations on the evolution and ecology of Neotoma (woodrats) in Idaho and northwestern Utah

2003 ◽  
Vol 59 (2) ◽  
pp. 160-171 ◽  
Author(s):  
Felisa A. Smith ◽  
Julio L. Betancourt
Keyword(s):  
Body Size ◽  
Body Mass ◽  
Spatial Relationship ◽  
Geographic Range ◽  
Climatic Fluctuations ◽  
Local Climate ◽  
South Central ◽  
Lower Elevation ◽  
Neotoma Cinerea ◽  
The Impact

AbstractAnimals respond to climatic change by adapting or by altering distributional patterns. How an animal responds is influenced by where it is positioned within its geographic range; the probability of extirpation is increased near range boundaries. Here, we examine the impact of Holocene climatic fluctuations on a small mammalian herbivore, the bushy-tailed woodrat (Neotoma cinerea), at five locations within south central Idaho and northwestern Utah. Previous work demonstrated that woodrats adapt to temperature shifts by altering body size. We focus here on the relationship between body mass, temperature, and location within the geographic range. Body mass is estimated by measuring fossil fecal pellets, a technique validated in earlier work. Overall, we find the predicted phenotypic response to climate change: animals were larger during cold periods, and smaller during warmer episodes. However, we also identify several time periods when changes in environmental temperature exceeded the adaptive flexibility of N. cinerea. A smaller-bodied species, the desert woodrat (N. lepida) apparently invaded lower elevation sites during the mid-Holocene, despite being behaviorally and physically subordinate to N. cinerea. Analysis of contemporary patterns of body size and thermal tolerances for both woodrat species suggests this was because of the greater heat tolerance of N. lepida. The robust spatial relationship between contemporary body size and ambient temperature is used as a proxy to reconstruct local climate during the Holocene.

scholarly journals Allometry of mitochondrial efficiency is set by metabolic intensity

2019 ◽  
Vol 286 (1911) ◽  
pp. 20191693 ◽  
Author(s):  
Boël Mélanie ◽  
Romestaing Caroline ◽  
Voituron Yann ◽  
Roussel Damien
Keyword(s):  
Metabolic Rate ◽  
Body Mass ◽  
Coupling Efficiency ◽  
Energy Output ◽  
Scaling Exponent ◽  
Metabolic Rates ◽  
Mammal Species ◽  
Skeletal Muscle Mitochondria ◽  
Metabolic Intensity ◽  
Mitochondrial Efficiency

Metabolic activity sets the rates of individual resource uptake from the environment and resource allocations. For this reason, the relationship with body size has been heavily documented from ecosystems to cells. Until now, most of the studies used the fluxes of oxygen as a proxy of energy output without knowledge of the efficiency of biological systems to convert oxygen into ATP. The aim of this study was to examine the allometry of coupling efficiency (ATP/O) of skeletal muscle mitochondria isolated from 12 mammal species ranging from 6 g to 550 kg. Mitochondrial efficiencies were measured at different steady states of phosphorylation. The efficiencies increased sharply at higher metabolic rates. We have shown that body mass dependence of mitochondrial efficiency depends on metabolic intensity in skeletal muscles of mammals. Mitochondrial efficiency positively depends on body mass when mitochondria are close to the basal metabolic rate; however, the efficiency is independent of body mass at the maximum metabolic rate. As a result, it follows that large mammals exhibit a faster dynamic increase in ATP/O than small species when mitochondria shift from basal to maximal activities. Finally, the invariant value of maximal coupling efficiency across mammal species could partly explain why scaling exponent values are very close to 1 at maximal metabolic rates.

Comparative physiology of suspension-feeding in living brachiopods and bivalves: evolutionary implications

Paleobiology ◽  
1993 ◽  
Vol 19 (3) ◽  
pp. 322-334 ◽  
Author(s):  
Melissa Clark Rhodes ◽  
R. J. Thompson
Keyword(s):  
Body Size ◽  
Fossil Record ◽  
Benthic Communities ◽  
Suspension Feeding ◽  
Metabolic Rates ◽  
Comparative Physiology ◽  
Feeding Rates ◽  
Bivalve Molluscs ◽  
Significant Component ◽  
Experimental Conditions

This paper presents scaling equations relating suspension-feeding rates to body size for articulate brachiopods and bivalve molluscs, two classes which represent a significant component of the fossil record of marine benthic communities. Clearance (feeding) rates of five species of living articulate brachiopods and three species of epifaunal suspension-feeding bivalve molluscs collected from mid-latitude fjords of Newfoundland and New Zealand were measured in similar experimental conditions. In comparisons within and between the two classes, we found that both plectolophous and spirolophous brachiopods had significantly lower feeding rates than mytilids, which are filibranchs, but that a sympatric primitive eulamellibranch veneroid bivalve had rates comparable to the brachiopods. Articulate brachiopods do not appear to feed effectively at the high algal concentrations which bivalves can exploit. The data on comparative suspension-feeding rates support the hypothesis that past changes in diversity and distribution of bivalves and brachiopods may be related to an overall increase in energy flux and escalation of metabolic rates during the Phanerozoic.

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