Mass, temperature and metabolic effects on discontinuous gas exchange cycles in eucalyptus-boring beetles (Coleoptera: cerambycidae)

2000 ◽  
Vol 203 (24) ◽  
pp. 3809-3820 ◽  
Author(s):  
M.A. Chappell ◽  
G.L. Rogowitz
Keyword(s):  
Gas Exchange ◽  
Water Conservation ◽  
Life Stage ◽  
Resting Metabolic Rate ◽  
Metabolic Effects ◽  
Cycle Frequency ◽  
Ambient Temperatures ◽  
Terrestrial Arthropods ◽  
Frequency Changes ◽  
Respiratory Evaporation

Ventilatory accommodation of changing metabolic rates is a relatively little-studied aspect of the discontinuous gas exchange cycles (DGCs) that occur in a wide variety of terrestrial arthropods. We used correlation analysis of resting metabolic rate (RMR, measured as the rate of CO(2) emission; V(CO2)) and several components of the DGC to examine accommodation to both temperature-induced changes and individual variation in RMR in two wood-boring beetles (Phorocantha recurva and P. semipunctata; Coleoptera: Cerambycidae).At low to moderate ambient temperatures (T(a); 10–20 degrees C), Phorocantha spp. displayed a characteristic DGC with relatively brief but pronounced open (O) phase bursts of CO(2) emission separated by longer periods of low V(CO2), the flutter (F) phase. However, the V(CO2) never fell to zero, and we could not reliably differentiate a typical closed (C) phase from the F phase. Accordingly, we pooled the C and F phases for analysis as the C+F phase. At higher T(a) (30 degrees C), the duration of the combined C+F phase was greatly reduced. There were no differences between the two species or between males and females in either RMR or characteristics of the DGC. We found large variation in the major DGC components (cycle frequency, durations and emission volumes of the O and C+F phases); much of this variation was significantly repeatable. Accommodation of temperature-induced RMR changes was almost entirely due to changes in frequency (primarily in the C+F phase), as has been found in several other discontinuously ventilating arthropods. Frequency changes also contributed to accommodation at constant T(a), but modulation of emission volumes (during both O and C+F phases) played a larger role in this case.The DGC is often viewed as a water conservation mechanism, on the basis that respiratory evaporation is minimal during the C and F phases. This hypothesis assumes that the F phase is primarily convective (because of a reduction in tracheal P(O2) and total intratracheal pressure during the C phase). To test this, we measured the DGC in beetles subjected to varying degrees of hypoxia in addition to normoxia. As predicted for a largely diffusive F phase, we found an increase in the volume of CO(2) emitted during the C+F phase in hypoxic conditions (10.4 % oxygen). This finding, together with a reduced tendency to utilize a DGC at high T(a) (when water stress is greatest) and a natural history in which water availability is probably not limiting for any life stage, suggests that a reduction of respiratory evaporation may not have been critical in the evolution of the DGC of Phorocantha spp. Instead, selection may have favored discontinuous ventilation because it facilitates gas exchange in the hypercapnic and hypoxic environments commonly encountered by animals (such as Phorocantha spp.) that live in confined spaces.

Effect of short-term exposure to high ambient temperatures on gas exchange and heat production in boars of different breeds

1998 ◽  
Vol 66 (2) ◽  
pp. 431-440 ◽  
Author(s):  
A.-H. Tauson ◽  
A. Chwalibog ◽  
J. Ludvigsen ◽  
K. Jakobsen ◽  
G. Thorbek
Keyword(s):  
Heat Stress ◽  
Gas Exchange ◽  
Heat Production ◽  
Live Weight ◽  
Mean Value ◽  
Short Term ◽  
Ambient Temperatures ◽  
Cooling Period ◽  
Basal Period ◽  
Short Term Exposure

AbstractThe effects of short-term exposure to high ambient temperatures on gas exchange, heat production (HE), respiration rate (RR) and rectal temperature were evaluated individually with boars of approximately 100 kg live weight. The boars were of different breeds with four of Yorkshire (YS), eight of Danish Landrace (DL), out of which three were found stress susceptible by the halothane test (DLH+), eight of Duroc (DR) and eight of Hampshire (HS) breeds. After 1 h rest in the respiration chamber at 17·0°C the gas exchange measurements started with al-h basal period at 17 °C, followed by 2h of heating during which temperature increased to 35·0 °C (period I) and then further to 39·7X1 (period II). Then cooling of the chamber started, and after 1 h (period III) temperature had decreased to 21·8°C, and after the 2nd h of cooling (period IV) temperature was 18·2 °C. The gas exchange was measured for each hour from 09.00 h (basal period) until 14.00 h (period IV). RR was recorded every 15 min. Rectal temperatures were measured when the animals were removed from the chamber. The gas exchange and HE increased slowly during period I but rapidly in period II, followed by decreasing values in the cooling periods. HS and DLH+ had considerably higher gas exchange and HE than other breeds in these two periods and the values remained high during period III. In period IV all breeds had gas exchange rates and HE below those of the basal period. RR increased slightly in period I and then a sharp increase followed during period II. Maximum RR was recorded in period III with an average of 183 breaths per min for all breeds. RR increased earlier and more steeply in HS and reached the highest mean value of 236 breaths per min. Four HS boars salivated heavily during heat stress and rectal temperatures of these animals were 39·7 °C when removed from the chamber compared with close to 39·0 °C for all other breeds. It was concluded that there were considerable breed differences in response to heat stress and that DLH+ and HS were more severely stressed than boars ofYS, DL and DR.

Laryngeal Phonatory Reflex

1975 ◽  
Vol 84 (2) ◽  
pp. 206-212 ◽  
Author(s):  
Masahiro Tanabe ◽  
Kazutomo Kitajima ◽  
Wilbur J. Gould
Keyword(s):  
Fundamental Frequency ◽  
Computer Analysis ◽  
Control Mechanism ◽  
Superior Laryngeal Nerve ◽  
Acoustic Signals ◽  
Laryngeal Nerve ◽  
Cycle Frequency ◽  
Internal Branch ◽  
Fine Control ◽  
Frequency Changes

The laryngeal phonatory reflex through the internal branch of the superior laryngeal nerve (SLN) was investigated by means of anesthetization of the nerve, after which acoustic signals were subjected to computer analysis to determine how anesthesia affected basic vocal parameters. Results showed that the anesthetization did not affect the abrupt cycle-to-cycle frequency changes and also did not influence the gross control of the fundamental frequency. But slower fluctuation of the fundamental frequency increased following anesthesia. From these results, it is suggested that the anesthetization of the internal branch of the SLN may derange the fine control mechanism of the larynx without affecting overall or gross performance of the phonatory apparatus.

scholarly journals Scaling of gas exchange cycle frequency in insects

2007 ◽  
Vol 4 (1) ◽  
pp. 127-129 ◽  
Author(s):  
John S Terblanche ◽  
Craig R White ◽  
Tim M Blackburn ◽  
Elrike Marais ◽  
Steven L Chown
Keyword(s):  
Gas Exchange ◽  
Size Range ◽  
Metabolic Rates ◽  
Large Database ◽  
Cyclic Pattern ◽  
Cycle Frequency ◽  
Mass Scaling ◽  
Scaling Relationship

Previously, it has been suggested that insect gas exchange cycle frequency ( f C ) is mass independent, making insects different from most other animals where periods typically scale as mass −0.25 . However, the claim for insects is based on studies of only a few closely related taxa encompassing a relatively small size range. Moreover, it is not known whether the type of gas exchange pattern (discontinuous versus cyclic) influences the f C –mass scaling relationship. Here, we analyse a large database to examine interspecific f C –mass scaling. In addition, we investigate the effect of mode of gas exchange on the f C –scaling relationship using both conventional and phylogenetically independent approaches. Cycle frequency is scaled as mass −0.280 (when accounting for phylogeneticnon-independence and gas exchange pattern), which did not differ significantly from mass −0.25 . The slope of the f C –mass relationship was shallower with a significantly lower intercept for the species showing discontinuous gas exchange than for those showing the cyclic pattern, probably due to lower metabolic rates in the former. Insects therefore appear no different from other animals insofar as the scaling of gas exchange f C is concerned, although gas exchange f C may scale in distinct ways for different patterns.

scholarly journals Physiological responses of Houbara bustards to high ambient temperatures

2002 ◽  
Vol 205 (4) ◽  
pp. 503-511 ◽  
Author(s):  
B. Irene Tieleman ◽  
Joseph B. Williams ◽  
Frédéric LaCroix ◽  
Patrick Paillat
Keyword(s):  
Heat Transfer ◽  
Body Composition ◽  
Physiological Responses ◽  
Resting Metabolic Rate ◽  
High Ambient Temperature ◽  
Physiological Mechanisms ◽  
Evaporative Water ◽  
Heat Gain ◽  
Ambient Temperatures ◽  
Dry Heat

SUMMARYDesert birds often experience a scarcity of drinking water and food and must survive episodes of high ambient temperature (Ta). The physiological mechanisms that promote survival during extended periods of high Ta have received little attention. We investigated the physiological responses of wild-caught and captive-reared Houbara bustards, Chlamydotis macqueenii, to Ta values ranging from below 0°C to 55°C, well above those in most previous studies of birds. Captive-reared Houbara bustards (mass 1245±242 g, N=7, mean ± s.d.) in summer have a resting metabolic rate (RMR) of 261.4 kJ day–1, 26 % below allometric predictions, and a total evaporative water loss (TEWL) at 25°C of 25.8 g day–1, 31 % below predictions. When Ta exceeded body temperature (Tb), the dry heat transfer coefficient decreased, a finding supporting the prediction that birds should minimize dry heat gain from the environment at high Ta values. Houbara bustards withstand high Ta values without becoming hyperthermic; at 45°C, Tb was on average 0.9°C higher than at 25°C. RMR and TEWL of captive-bred Houbara bustards were 23 % and 46 % higher in winter than in summer, respectively. Captive-reared Houbara bustards had a 17 % lower RMR and a 28 % lower TEWL than wild-born birds with similar genetic backgrounds. Differences in body composition between wild-caught and captive-reared birds were correlated with differences in physiological performance.

scholarly journals Water Conservation in Terrestrial Arthropods

Nature ◽  
1950 ◽  
Vol 166 (4228) ◽  
pp. 809-810
Author(s):  
A. D. LEES
Keyword(s):  
Water Conservation ◽  
Terrestrial Arthropods

Effect of age on cold acclimation in rats: metabolic and behavioral responses

1991 ◽  
Vol 260 (2) ◽  
pp. R284-R289 ◽  
Author(s):  
T. L. Owen ◽  
R. L. Spencer ◽  
S. P. Duckles
Keyword(s):  
Body Temperature ◽  
Metabolic Rate ◽  
Cold Acclimation ◽  
Cold Exposure ◽  
Resting Metabolic Rate ◽  
Age Groups ◽  
Behavioral Responses ◽  
Mortality And Morbidity ◽  
Ambient Temperatures ◽  
Reduced Body

To determine whether senescence affects the metabolic and behavioral responses of rats to chronic cold exposure, 8- and 22-mo-old male Fischer 344 rats were studied before and after 6 wk of cold (6-10 degrees C) exposure. Measurements of body weight, food consumption, oxygen consumption, body temperature, and ambient temperature selection in a thermocline (7-37 degrees C linear gradient) were made at regular intervals throughout the acclimation period. Before acclimation, age groups differed significantly only by weight. During acclimation, older rats had increased mortality and morbidity below 10 degrees C. After acclimation at 10 degrees C, younger and older rats both selected cooler ambient temperatures (7 and 5 degrees C cooler than preacclimation, respectively), and older rats had a significantly greater decrease in body temperature in the thermocline. Both age groups increased resting metabolic rate at 25 degrees C with cold acclimation (16.5 and 10% increase for younger and older rats, respectively). This study indicates distinct differences in metabolic and behavioral responses of younger and older rats to cold acclimation. Chronic cold exposure is detrimental to thermoregulatory function in older rats, since it is not as effective in stimulating sustained increases in metabolic rate in older rats as in young adults and it leads to a preference for cooler ambient temperatures, resulting in increased heat loss and reduced body temperature.

scholarly journals Avian adaptations to the Kalahari environment: A typical continental semidesert

Koedoe ◽  
1984 ◽  
Vol 27 (2) ◽  
Author(s):  
G. L Maclean
Keyword(s):  
Parental Care ◽  
Body Condition ◽  
Water Conservation ◽  
Bird Species ◽  
Ecological Effects ◽  
Breeding Ground ◽  
Ambient Temperatures ◽  
Hypertonic Solutions ◽  
Time Of Year ◽  
Nasal Glands

Bird species adapted to the Kalahari are generally either (a) sedentary, insectivorous (or carnivorous) and non-gregarious, or (b) nomadic, granivorous and gregarious even when breeding. Ground-dwelling birds predominate numerically and are cryptically coloured to avoid predation. Many species have nasal glands which secrete hypertonic solutions in response to the intake of fluids with high solute concentrations, as an adaptation to water conservation. Thermoregulation is discussed especially in relation to high ambient temperatures. Breeding is initiated in most species by rainfall or associated ecological effects, correlated with improved body condition of the females; lag periods between rain and egglaying are related to diet and time of year. Nest orientation is also related to season and capitalizes on maximal shade in summer. Parental care in sandgrouse is discussed.

scholarly journals An experimental evolution study confirms that discontinuous gas exchange does not contribute to body water conservation in locusts

2016 ◽  
Vol 12 (12) ◽  
pp. 20160807 ◽  
Author(s):  
Stav Talal ◽  
Amir Ayali ◽  
Eran Gefen
Keyword(s):  
Gas Exchange ◽  
Water Loss ◽  
Experimental Evolution ◽  
Water Conservation ◽  
Locusta Migratoria ◽  
Body Water ◽  
Evaporative Water ◽  
Migratory Locust ◽  
Evolutionary Response ◽  
Evolution Study

The adaptive nature of discontinuous gas exchange (DGE) in insects is contentious. The classic ‘hygric hypothesis’, which posits that DGE serves to reduce respiratory water loss (RWL), is still the best supported. We thus focused on the hygric hypothesis in this first-ever experimental evolution study of any of the competing adaptive hypotheses. We compared populations of the migratory locust ( Locusta migratoria ) that underwent 10 consecutive generations of selection for desiccation resistance with control populations. Selected locusts survived 36% longer under desiccation stress but DGE prevalence did not differ between these and control populations (approx. 75%). Evolved changes in DGE properties in the selected locusts included longer cycle and interburst durations. However, in contrast with predictions of the hygric hypothesis, these changes were not associated with reduced RWL rates. Other responses observed in the selected locusts were higher body water content when hydrated and lower total evaporative water loss rates. Hence, our data suggest that DGE cycle properties in selected locusts are a consequence of an evolved increased ability to store water, and thus an improved capacity to buffer accumulated CO 2 , rather than an adaptive response to desiccation. We conclude that DGE is unlikely to be an evolutionary response to dehydration challenge in locusts.

Temperature regulation in the new-born lamb. VI. Heat exchanges in lambs in a hot environment

1962 ◽  
Vol 13 (1) ◽  
pp. 122 ◽  
Author(s):  
G Alexander ◽  
D Williams
Keyword(s):  
Water Loss ◽  
Good Evidence ◽  
Sweat Glands ◽  
Second Phase ◽  
Ambient Temperatures ◽  
Respiratory Loss ◽  
Air Temperatures ◽  
Cutaneous Evaporation ◽  
Heat Exchanges ◽  
Respiratory Evaporation

At ambient temperatures below about 30°C, respiratory and cutaneous evaporation were constant in normal lambs and lambs without sweat glands. Above 30°C, respiratory water loss increased steeply. Cutaneous water loss also increased, but at a slower rate than respiratory loss and only in the lambs with sweat glands. The efficiency of evaporation in cooling the lamb was close to 100%. The contribution of cutaneous blood flow to facilitation of heat loss in lambs lying down appeared to be low. At low environmental humidity, respiratory evaporation at all rates of normal shallow panting was approximately 4 mg per respiration; but in "second phase" breathing this was increased up to 12 mg per respiration, and total respiratory evaporation was not reduced. Lambs showed no evidence of distress when exposed for 6–12 hr to air temperatures of 40°C and water vapour pressures of' less than I5 mm Hg. Cutaneous loss tended to fall and respiratory loss to increase. Maximum rates of cutaneous and respiratory evaporation were estimated by suppressing evaporation from the skin or respiratory tract at 43°C. These values tended to be higher in crossbred lambs then in Merinos, and Merinos tended to reach maximum "sweating" rates under less severe heat stress than the crossbreds. Homeothermic equilibrium was approached when evaporation from neither site was suppressed, but rectal temperatures increased rapidly when cutaneous evaporation was prevented, and more rapidly still when respiratory evaporation was much reduced. The results also illustrate how a high metabolic rate decreases heat tolerance. These experiments provide good evidence that sheep do sweat, but that respiratory evaporation is quantitatively more important than sweating.

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