Metabolic rate and respiratory gas-exchange patterns in tenebrionid beetles from the Negev Highlands, Israel

2002 ◽  
Vol 205 (6) ◽  
pp. 791-798 ◽  
Author(s):  
Frances D. Duncan ◽  
Boris Krasnov ◽  
Megan McMaster
Keyword(s):  
Gas Exchange ◽  
Metabolic Rate ◽  
Water Loss ◽  
Activity Patterns ◽  
High Water ◽  
Standard Metabolic Rate ◽  
Active Species ◽  
Habitat Associations ◽  
Diel Activity ◽  
Water Vapour Pressure

SUMMARY This study correlates the pattern of external gas exchange with the diel activity of nine species of tenebrionid beetle from the Negev Desert, Israel. The study species are active throughout the summer months when daytime temperatures are high and no rain falls. There were no differences in standard metabolic rate, determined by flow-through respirometry, among the nine species. All the nocturnally active beetles exhibited a form of continuous respiration, whereas the two diurnally active and one crepuscular species exhibited a cyclic form of respiration referred to as the discontinuous gas-exchange cycle (DGC). The DGCs recorded have a long flutter period consisting of miniature ventilations, and 29–48 % of the total CO2 output occurred during this period. In this study, the flutter period played an important role in the modulation of metabolic rate, in contrast to other studies in which the burst period has been shown to be important. We suggest that the long flutter period is important in reducing respiratory water loss in arid-dwelling arthropods. This study lends support to the hypothesis that discontinuous gas exchange is important in reducing respiratory water loss from beetles that need to minimise dessication because of the high water vapour pressure gradient they experience. If the use of underground burrows were responsible for the evolution of discontinuous gas exchange, then we would expect all nine tenebrionid species to use DGCs since both the nocturnally and diurnally active species bury in the sand during periods of inactivity. We conclude that the activity patterns of the beetles are more important than their habitat associations in designating the type of respiration used.

scholarly journals Water Costs of Gas Exchange by a Speckled Cockroach and a Darkling Beetle

Insects ◽  
2020 ◽  
Vol 11 (9) ◽  
pp. 632
Author(s):  
Waseem Abbas ◽  
Philip C. Withers ◽  
Theodore A. Evans
Keyword(s):  
Body Size ◽  
Gas Exchange ◽  
Metabolic Rate ◽  
Water Loss ◽  
Evaporative Water ◽  
Factors Affecting ◽  
Darkling Beetle ◽  
Terrestrial Insects ◽  
Exchange Patterns ◽  
Respiratory Cost

Respiratory water loss during metabolic gas exchange is an unavoidable cost of living for terrestrial insects. It has been suggested to depend on several factors, such as the mode of gas exchange (convective vs. diffusive), species habitat (aridity), body size and measurement conditions (temperature). We measured this cost in terms of respiratory water loss relative to metabolic rate (respiratory water cost of gas exchange; RWL/V˙CO2) for adults of two insect species, the speckled cockroach (Nauphoeta cinerea) and the darkling beetle (Zophobas morio), which are similar in their mode of gas exchange (dominantly convective), habitat (mesic), body size and measurement conditions, by measuring gas exchange patterns using flow-through respirometry. The speckled cockroaches showed both continuous and discontinuous gas exchange patterns, which had significantly a different metabolic rate and respiratory water loss but the same respiratory water cost of gas exchange. The darkling beetles showed continuous gas exchange pattern only, and their metabolic rate, respiratory water loss and respiratory cost of gas exchange were equivalent to those cockroaches using continuous gas exchange. This outcome from our study highlights that the respiratory water cost of gas exchange is similar between species, regardless of gas exchange pattern used, when the confounding factors affecting this cost are controlled. However, the total evaporative water cost of gas exchange is much higher than the respiratory cost because cuticular water loss contributes considerably more to the overall evaporative water loss than respiratory water. We suggest that the total water cost of gas exchange is likely to be a more useful index of environmental adaptation (e.g., aridity) than just the respiratory water cost.

Influence of Temperature and Current Speed on the Swimming Capacity of Lake Whitefish (Coregonus clupeaformis) and Cisco (C. artedii)

1985 ◽  
Vol 42 (9) ◽  
pp. 1522-1529 ◽  
Author(s):  
Louis Bernatchez ◽  
Julian J. Dodson
Keyword(s):  
Metabolic Rate ◽  
Swimming Speed ◽  
Swimming Performance ◽  
High Water ◽  
Standard Metabolic Rate ◽  
Coregonus Clupeaformis ◽  
Lake Whitefish ◽  
Influence Of Temperature ◽  
Speed Range ◽  
Swimming Endurance

We tested the influence of temperature and water velocity on metabolic rate and swimming performance of lake whitefish (Coregonus clupeaformis) and Cisco (C. artedii) using respirometry techniques. Tests were conducted at 5, 12, and 17 °C (speed range 20–102 cm∙s−1) for fake whitefish and at 12 °C (speed range 20–63 cm∙s−1) for cisco. Fish lengths ranged from 10 to 39 cm (TL). The net aerobic cost of swimming, obtained by subtracting standard from total oxygen consumption, was twice as high for cisco as that for lake whitefish at any swimming speed. However, the standard metabolic rate of lake whitefish was almost the double that of cisco acclimated to the same temperature. Values of metabolic scope for activity coupled with the net cost of swimming showed that coregonines were not good performers compared with most salmonids. The active metabolic rate, scope for activity, and critical swimming speed for lake whitefish were maximal at 12 °C and minimal at 5 °C. Swimming endurance of lake whitefish decreased logarithmically with swimming speed and was reduced at low temperature, the distance traversed at any given swimming speed being minimal at 5 °C. Our results support the hypothesis that the combined effect of high water velocities and low ambient temperature on coregonines' metabolism and swimming performance may be a more important factor than specific spawning temperature in the timing of the early reproductive migration of anadromous coregonines in the Eastmain River, James Bay.

scholarly journals Intra-individual variation allows an explicit test of the hygric hypothesis for discontinuous gas exchange in insects

2009 ◽  
Vol 6 (2) ◽  
pp. 274-277 ◽  
Author(s):  
Caroline M. Williams ◽  
Shannon L. Pelini ◽  
Jessica J. Hellmann ◽  
Brent J. Sinclair
Keyword(s):  
Carbon Dioxide ◽  
Gas Exchange ◽  
Metabolic Rate ◽  
Water Loss ◽  
Individual Variation ◽  
Loss Reduction ◽  
Total Water ◽  
Explicit Test ◽  
Carbon Dioxide Release ◽  
Flow Through

The hygric hypothesis postulates that insect discontinuous gas exchange cycles (DGCs) are an adaptation that reduces respiratory water loss (RWL), but evidence is lacking for reduction of water loss by insects expressing DGCs under normal ecological conditions. Larvae of Erynnis propertius (Lepidoptera: Hesperiidae) naturally switch between DGCs and continuous gas exchange (CGE), allowing flow-through respirometry comparisons of water loss between the two modes. Water loss was lower during DGCs than CGE, both between individuals using different patterns and within individuals using both patterns. The hygric cost of gas exchange (water loss associated with carbon dioxide release) and the contribution of respiratory to total water loss were lower during DGCs. Metabolic rate did not differ between DGCs and CGE. Thus, DGCs reduce RWL in E. propertius , which is consistent with the suggestion that water loss reduction could account for the evolutionary origin and/or maintenance of DGCs in insects.

scholarly journals The role of ambient temperature and body mass on body temperature, standard metabolic rate and evaporative water loss in southern African anurans of different habitat specialisation

PeerJ ◽  
2019 ◽  
Vol 7 ◽  
pp. e7885 ◽  
Author(s):  
Mohlamatsane Mokhatla ◽  
John Measey ◽  
Ben Smit
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Body Mass ◽  
Water Loss ◽  
Standard Metabolic Rate ◽  
Evaporative Water Loss ◽  
Evaporative Water ◽  
Habitat Specialisation ◽  
Wide Range

Temperature and water availability are two of the most important variables affecting all aspects of an anuran’s key physiological processes such as body temperature (Tb), evaporative water loss (EWL) and standard metabolic rate (SMR). Since anurans display pronounced sexual dimorphism, evidence suggests that these processes are further influenced by other factors such as vapour pressure deficit (VPD), sex and body mass (Mb). However, a limited number of studies have tested the generality of these results across a wide range of ecologically relevant ambient temperatures (Ta), while taking habitat use into account. Thus, the aim of this study was to investigate the role of Ta on Tb, whole-animal EWL and whole-animal SMR in three wild caught African anuran species with different ecological specialisations: the principally aquatic African clawed frog (Xenopus laevis), stream-breeding common river frog (Amietia delalandii), and the largely terrestrial raucous toad (Sclerophrys capensis). Experiments were conducted at a range of test temperatures (5–35 °C, at 5 °C increments). We found that VPD better predicted rates of EWL than Ta in two of the three species considered. Moreover, we found that Tb, whole-animal EWL and whole-animal SMR increased with increasing Ta, while Tb increased with increasing Mb in A. delalandii and S. capensis but not in X. laevis. Whole-animal SMR increased with increasing Mb in S. capensis only. We did not find any significant effect of VPD, Mb or sex on whole-animal EWL within species. Lastly, Mb did not influence Tb, whole-animal SMR and EWL in the principally aquatic X. laevis. These results suggest that Mb may not have the same effect on key physiological variables, and that the influence of Mb may also depend on the species ecological specialisation. Thus, the generality of Mb as an important factor should be taken in the context of both physiology and species habitat specialisation.

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