Variation In Thermal Environment Research Articles

Combined effects of thermal environment and gene regulation on metabolic enzyme activities of major metabolic tissues in a winter-breeding amphibian

Variations in thermal environments can provoke diverse physiological responses in amphibians. Despite extensive studies on the thermal sensitivity of amphibian metabolic physiology, including enzyme activity at different temperatures, the rationale for selecting specific metabolic enzymes and their relationship with gene expression remains unclear. Cytochrome c oxidase (CCO), succinate dehydrogenase (SDH), and lactate dehydrogenase (LDH) are key metabolic enzymes within the primary metabolic regulatory tissues of animals. Through a comparative analysis of the effects of two different thermal conditions (12 and 18 °C) on the activities and mRNA expression levels of these enzymes within the kidney and liver tissues of a winter-breeding amphibian (Leptobrachium liui), with the field group during the breeding season as the control, we provide insights into the interplay between temperature and gene expression. The mRNA levels of CCO subunits 1 (cox1), 2 (cox2), and 3 (cox3), and LDH subunit A (ldha) were significantly higher in the kidney than in the liver of all individuals. High-temperature acclimation resulted in significantly decreased expression levels of cox1-3, ldha, and SDH complex flavoprotein subunit A (sdha) in the kidney. In the liver, the expression levels of sdha and ldha significantly reduced under high-temperature treatment, whereas cox3 expression increased. SDH and LDH activities displayed tissue-specific variations, while no significant differences in CCO activity were observed between tissues. CCO, SDH, and LDH activities in both liver and kidney tissues significantly declined after high-temperature acclimation, but simultaneously increased with up-regulated gene expression, indicating that the thermal environment and corresponding gene expression combined affect the activities of these metabolic enzymes. In conclusion, the thermal environment is a key factor affecting the physiological and biochemical responses of L. liui. Prolonged exposure to high temperatures during the breeding season could inhibit the activity of primary metabolic enzymes in the winter-breeding amphibian.

A systematic review on thermal environment and thermal comfort studies in Chinese residential buildings

Amid the backdrop of the energy crisis, thermal comfort is crucial to achieve energy savings. Residential buildings are characterized by a wide range of adaptive comfort opportunities. However, there has been a lack of systematic refinement and review of residential thermal comfort field studies in China to provide valuable recommendations for energy conservation. We systematically reviewed studies on thermal environment and thermal comfort in Chinese residential buildings published in peer-reviewed journals up to 2020. A total of 34 studies were deemed to have provided sufficient information on both the thermal environment and thermal comfort. We found that in winter, there were obvious differences between urban and rural dwellings in Severe Cold (SC) and Cold (C) zones, with regard to their indoor air temperature (urban: 19.8 ∼ 25.0 °C v.s. rural: 11.3 ∼ 17.8 °C) and neutral temperature (urban: 17.6 ∼ 25.1 °C v.s. rural: 11.9 ∼ 23.45 °C). While in summer, the indoor air temperature in urban dwellings were slightly lower than those in rural areas due to their prevalent use of air conditioner (urban: 26.1 ∼ 28.9 °C v.s. rural: 29.5 ∼ 34.9 °C). Indoor air temperature and neutral temperature varied considerably in different climate zones in winter. In SC zones, the indoor environment was overheated, which could lead to energy wastage and overheating discomfort for residents. Residents in Hot-Summer and Cold-Winter (HSCW) zone were the most tolerant to the variation of thermal environment (the median coefficient of MTS or TSV equation: SC: 0.18; C: 0.20; HSCW: 0.13; HSWW: 0.23).

Monitoring thermal environment deterioration and its dynamic response to urban expansion in Wuhan, China

Understanding how urban heat island (UHI) effect responds to urbanization is of great significance to develop appropriate UHI mitigation measures. However, the dynamic response of thermal environment to urban expansion is still less discussed. In this study, the spatiotemporal variation of thermal characteristics and its dynamic response to urbanization was monitored at the pixel level in 1987, 1996, 2007 and 2016 in Wuhan, China based on multi-temporal remotely sensed images. The results indicate that Wuhan experienced significant thermal deterioration during the 29-year period, which was largely attributed to the rapid urbanization from 1996 to 2007. Due to the high spatial heterogeneity of urban development, the thermal characteristic variation did not always spatially correspond to urbanization process. The urbanization dynamics alone can explain only 14.84% ~ 36.37% of the spatiotemporal variation in thermal environment throughout the study area. Nevertheless, the thermally deteriorated areas had good spatial consistence with the rapidly developed areas in all cases, suggesting that urban development could better explain the dynamic characteristics of thermal environment in more rapidly urbanized areas (with the R2 values of 0.7013–0.9989). An obvious “context effect” was detected during the dynamic influence of urban development on thermal environment variation. Urban development based on the increase of construction density only strengthened UHI intensity, but contributed little to the spread of thermal environment deterioration. Urban expansion with amounts of newly expanded construction land should be responsible for thermal environment deterioration. These findings provide detailed information and sound evidence to adjust urban planning options accordingly to improve thermal environment.

Synchronously improved reliability, figure of merit and adhesion of flexible copper nanowire networks by chitosan transition

Copper nanowires (CuNWs) are remarkable components that can replace indium tin oxide as transparent electrodes due to their low cost, high conductivity and acceptable transmittance. However, a common coating method can cause poor electrical, optical and adhesive properties because of the creation of loosely connected junctions. In addition, the unsatisfactory thermal and environmental stabilities limit the practical applications. These problems should be overcome in CuNW-based films for reliable transparent electrodes through material and engineering approaches. In this work, a novel transparent composite electrode composed of chitosan and CuNWs on a flexible polyethylene terephthalate (PET) substrate, with synchronously strengthened adhesion, as well as heightened transmittance, reduced resistivity, improved flexibility, enhanced thermal stability and increased environmental stability, was prepared without vacuum processing and high-temperature annealing. The effects of the number of CuNW network layers and chitosan concentration on the performance of chitosan/CuNW composite transparent electrodes were studied. The resulting electrodes exhibitan excellent conductivity (sheet resistance: 15.6 Ω sq−1) and a superior optical transmittance (∼87%) at 550 nm. Calculation of the figure of merit displays a high value of 168, which is the highest among all the reported CuNW-based transparent electrodes. Meanwhile, the sheet resistance did not show great change after 10 tape tests and 10 000 bending cycles, suggesting good adhesion to the PET substrate and outstanding mechanical flexibility. Moreover, the composite transparent electrodes show good stability to resist long-term storage and temperature variation in thermal environment.

Vibration and nonlinear dynamic analysis of variable thickness sandwich laminated composite panel in thermal environment

Based on the first-order shear deformation theory taking into account geometrical nonlinearity, initial geometrical imperfection, vibration and nonlinear dynamic analysis of the sandwich laminated composite panel characterized by a continuous thickness variation in thermal environment and resting on an elastic foundation are considered in this paper. Variable thickness could affect the design of composite panel since it allows to tailor the stiffness features in the most stressed areas within the domain, keeping the weight constant. As a consequence, an improved dynamic behavior of the structure may be exhibited. The motion equations of dynamic analysis are determined due to Galerkin method and the obtained equation is numerically solved by using Runge–Kutta method. In numerical results, the effects of initial geometrical imperfections and geometrical parameters, material properties, coefficients of foundation, mechanical loads, temperature and the variable thickness on the nonlinear dynamic response and vibration of the laminated composite panel are investigated.

Multi-scale effects of urban agglomeration on thermal environment: A case of the Yangtze River Delta Megaregion, China

The phenomenon of urban heat islands has been extensively investigated in recent decades. Due to the complexity of urban systems, this phenomenon may be scale-dependent, particularly for large megaregions where a cluster of cities gather together. Despite many studies focusing on urban heat islands at scales from single-site to regional, and further to global, there are few studies addressing multi-scale effects of large urban agglomeration on thermal environment. In this study, we used the Yangtze River Delta (YRD), one of China's most important megaregions, as a pilot case to examine the spatial-temporal variations of thermal environment and its driving forces at two spatial scales in 2000, 2005 and 2010. At regional scale, the effect of the entire megaregion on thermal environment was characterized by the distribution of the highest surface temperature zone (HTZ), which was closely related to the occurrence of continuously developed land. At city scale, the effect of individual city on thermal environment was characterized by the mean land surface temperature difference (LSTD) between urban and rural areas, which showed a significant positive correlation with the economic factors. In the YRD, the secondary industry output could explain approximately 58% and 39% of the variation of the LSTD in 2000 and 2005, respectively, while in 2010 the tertiary industry output became the important factor and accounted for 36% of the variation of LSTD. Finally, cities with fast urban economic growth rate and large size of urban areas were the priority for adopting more efficient strategies to urban thermal management.

Behavioral adaptations in Ameivula ocellifera (Squamata: Teiidae) in response to thermal environmental changes

Behavioral adaptations in Ameivula ocellifera (Squamata: Teiidae) in response to thermal environmental changes. Lizards rely on external sources to regulate body temperature, but in many species, it is not known whether lizards are able to change their thermoregulatory behaviors in response to variations in thermal environments. The seasonal thermal ecology of three populations of the Brazilian whiptail lizard, Ameivula ocellifera, in northeastern Brazil (two Caatinga sites and one in the Atlantic Forest) was investigated. The relationships between body temperature and microhabitat temperatures (substrate and air), and between body temperature and thermoregulatory behavior (i.e., time of exposure to sunlight classes and time spent basking) were explored. The average body temperatures of the lizards were 38–39°C; these neither varied seasonally nor among populations. Substrate and air temperatures are lower at the natural Caatinga site, and lizards in there spent less time in the shade and more time exposed to the sun. Microhabitat temperatures vary seasonally in natural Caatinga; they are lower in the rainy season, when lizards spent more time exposed to sun and less time in fltered sun. Lizard body temperatures exceeded microhabitat temperatures in the rainy season in all three populations; however, they did not exceed substrate temperature in the dry season. In each of the populations, lizards with low body temperatures during cloudy conditions spent more time basking. Thus, A. ocellifera adjusts its body temperature behaviorally to compensate for seasonal changes in environmental temperatures, as well as geographic thermal variation throughout its range.

The impact of thermal environment on occupant IEQ perception and productivity

In this paper, the effects of thermal environment on occupant IEQ perception and productivity were studied. Seven groups of experiments were carried out in a controlled office environment and the physical parameters, including air temperature, globe temperature, relative humidity, carbon dioxide concentration, illuminance and background noise level, were measured. In the experiments, indoor air temperature was the independent variable, which varied from 16 °C to 28 °C with a step of 2 °C, and other constant IEQ parameters were the control variables. The dependent variable would be human perception of various control variables and productivity. Subjects (9 females and 12 males) were recruited to participate every experiment for 2 h. During each experiment, they voted their perceptions of thermal comfort, indoor air quality, lighting and acoustic environment, and performed simulated office tasks to evaluate the productivity. The results showed that the variation of thermal environment not only affected thermal comfort but also had a “comparative” impact on the perception of other IEQ factors. When thermal environment was unsatisfactory, it weakened the “comfort expectation” of other IEQ factors, which accordingly resulted in the less dissatisfaction with other IEQ factors. Conversely, when thermal environment was quite satisfying, it raised “comfort expectation” of other IEQ factors, which lowered the evaluation of the real performance of other IEQ factors retroactively. The quantitative relationship between productivity and thermal environment was established. The optimal productivity was obtained when people felt “neutral” or “slightly cool”, and the increase of thermal satisfaction had a positive effect on productivity.

The Impact of Greenspace on Thermal Comfort in a Residential Quarter of Beijing, China.

With the process of urbanization, a large number of residential quarters, which is the main dwelling form in the urban area of Beijing, have been developed in last three decades to accommodate the rising population. In the context of intensification of urban heat island (UHI), the potential degradation of the thermal environment of residential quarters can give rise to a variety of problems affecting inhabitants’ health. This paper reports the results of a numerical study of the thermal conditions of a residential quarter on a typical summertime day under four greening modification scenarios, characterized by different leaf area density (LAD) profiles. The modelling results demonstrated that vegetation could evidently reduce near-surface air temperature, with the combination of grass and mature trees achieving as much as 1.5 °C of air temperature decrease compared with the non-green scenario. Vegetation can also lead to smaller air temperature fluctuations, which contribute to a more stable microclimate. The Universal Thermal Climate Index (UTCI) was then calculated to represent the variation of thermal environment of the study area. While grass is helpful in improving outdoor thermal comfort, trees are more effective in reducing the duration and expansion of suffering from severe heat stress. The results of this study showed that proper maintenance of vegetation, especially trees, is significant to improving the outdoor thermal environment in the summer season. In consideration of the deficiency of the current code in the management of greenspace in residential areas, we hope the results reported here will help promote the improvement of the code and related regulations for greenspace management.

Variation of Thermal Environment and its Effect on Performance of Wheat (Triticum aestivum L.) Under Future Global Warming

Variation of Thermal Environment and its Effect on Performance of Wheat (Triticum aestivum L.) Under Future Global Warming

Immobile and Mobile Life-History Stages Have Different Thermal Physiologies in a Lizard

Temperature affects multiple aspects of an organism's biology and thus defines a major axis of the fundamental niche. For ectotherms, variation in the thermal environment is particularly important because most of these taxa have a limited capacity to thermoregulate via metabolic heat production. While temperature affects all life-history stages, stages can differ in their ability to respond to the thermal environment. For example, in oviparous organisms, free-living adults can behaviorally thermoregulate, whereas developing embryos are at the mercy of the nest environment. These differences in the realized thermal environment should select for life-history stages to have different thermal tolerances, although this has been rarely examined. I tested the hypothesis that stage-specific thermal reaction norms can evolve independently by using southern alligator lizards (Elgaria multicarinata, Anguidae). Using incubation experiments (five temperatures: 24°, 26°, 28°, 30°, and 32°C), I described the thermal reaction norm for embryonic development and compared these results to previous studies on the thermal ecology of adults. Offspring survivorship and morphology were similarly affected by incubation temperature. While developing embryos had the same optimum temperature as adults (approximately 28°C), the breadth of their thermal reaction norms differed. My results suggest that developing embryos of E. multicarinata are more sensitive to variation in the average thermal environment than are adults. Variation in the thermal sensitivity of life-history stages might be common and has implications for how organisms respond to variation in the thermal environment. Identifying those life-history stages that are most sensitive/limiting will be important for developing models that best predict species' responses to impending environmental change.

Maturation of Eugenia pyriformis seeds under different hydric and thermal conditions

This study aims to analyze the maturation and dispersal of Eugenia pyriformis Cambess. seeds produced in different years, and the influence of variation in thermal and hydric environment on seed physical and physiological characteristics at dispersal. Fruits at different developmental stages were harvested in the city of São Paulo between 2003 and 2010, as well as in the cities of Campinas and Lavras, in 2009 and 2010 and analyzed for size and color. The seeds were extracted from the fruits and their dry mass, water content, germination and vigor were assessed. Results showed that seed maturation is unsynchronized to the maturation of the fruit, taking 45 days on average (430 growing degree-days), longer in rainy times or lower temperatures. Seeds with higher physiological quality were produced in rainy years and when the temperature range was larger. We concluded therefore that hydric and thermal environmental variations during development influence the maturation of Eugenia pyriformis seeds and are able to determine the formation cycle and the final seed quality.

Molecular Cloning and Functional Characterization of Xenopus tropicalis Frog Transient Receptor Potential Vanilloid 1 Reveal Its Functional Evolution for Heat, Acid, and Capsaicin Sensitivities in Terrestrial Vertebrates

The functional difference of thermosensitive transient receptor potential (TRP) channels in the evolutionary context has attracted attention, but thus far little information is available on the TRP vanilloid 1 (TRPV1) function of amphibians, which diverged earliest from terrestrial vertebrate lineages. In this study we cloned Xenopus tropicalis frog TRPV1 (xtTRPV1), and functional characterization was performed using HeLa cells heterologously expressing xtTRPV1 (xtTRPV1-HeLa) and dorsal root ganglion neurons isolated from X. tropicalis (xtDRG neurons) by measuring changes in the intracellular calcium concentration ([Ca(2+)](i)). The channel activity was also observed in xtTRPV1-expressing Xenopus oocytes. Furthermore, we tested capsaicin- and heat-induced nocifensive behaviors of the frog X. tropicalis in vivo. At the amino acid level, xtTRPV1 displays ∼60% sequence identity to other terrestrial vertebrate TRPV1 orthologues. Capsaicin induced [Ca(2+)](i) increases in xtTRPV1-HeLa and xtDRG neurons and evoked nocifensive behavior in X. tropicalis. However, its sensitivity was extremely low compared with mammalian orthologues. Low extracellular pH and heat activated xtTRPV1-HeLa and xtDRG neurons. Heat also evoked nocifensive behavior. In oocytes expressing xtTRPV1, inward currents were elicited by heat and low extracellular pH. Mutagenesis analysis revealed that two amino acids (tyrosine 523 and alanine 561) were responsible for the low sensitivity to capsaicin. Taken together, our results indicate that xtTRPV1 functions as a polymodal receptor similar to its mammalian orthologues. The present study demonstrates that TRPV1 functions as a heat- and acid-sensitive channel in the ancestor of terrestrial vertebrates. Because it is possible to examine vanilloid and heat sensitivities in vitro and in vivo, X. tropicalis could be the ideal experimental lower vertebrate animal for the study of TRPV1 function.

Silicon photonics manufacturing

Most demonstrations in silicon photonics are done with single devices that are targeted for use in future systems. One of the costs of operating multiple devices concurrently on a chip in a system application is the power needed to properly space resonant device frequencies on a system's frequency grid. We asses this power requirement by quantifying the source and impact of process induced resonant frequency variation for microdisk resonators across individual die, entire wafers and wafer lots for separate process runs. Additionally we introduce a new technique, utilizing the Transverse Electric (TE) and Transverse Magnetic (TM) modes in microdisks, to extract thickness and width variations across wafers and dice. Through our analysis we find that a standard six inch Silicon on Insulator (SOI) 0.35 μm process controls microdisk resonant frequencies for the TE fundamental resonances to within 1 THz across a wafer and 105 GHz within a single die. Based on demonstrated thermal tuner technology, a stable manufacturing process exhibiting this level of variation can limit the resonance trimming power per resonant device to 231 μW. Taken in conjunction with the power to compensate for thermal environmental variations, the expected power requirement to compensate for fabrication-induced non-uniformities is 17% of that total. This leads to the prediction that thermal tuning efficiency is likely to have the most dominant impact on the overall power budget of silicon photonics resonator technology.

電気式床暖房室内の熱放射場に関する実験的研究

Thermal radiation field in a room with electric floor heating was investigated by experiments using a cubic net radiometer. The surface temperature of the floor was set at a high temperature of 50 degree centigrade at the highest, for the sake of conducting an evaluation method of thermal environment in the room with floor heating. The height of measurement was selected at 50cm above the floor corresponding to the posture of a human body sitting on the floor. Using the cubic net radiometer made it possible to analyze the variation of thermal environment in the room owing to the directionality of the instrument.

Diurnal variation in thermal environment experienced by salmonids in the North Pacific as indicated by data storage tags

Eight temperature-recording data storage tags were recovered from three salmonids in Alaska (pink and coho salmon and steelhead trout) and five chum salmon in Japan after 21–117 days, containing the first long-term records of ambient temperature from Pacific salmonids migrating at sea. Temperature data imply diel patterns of descents to deeper, cooler water and ascents to the surface. Fish were found at higher average temperatures at night, with narrower temperature ranges and fewer descents than during the day. Fish tagged in the Gulf of Alaska were at higher temperatures on average (10–12°C) than chum salmon tagged in the Bering Sea (8–10°C). Chum salmon were also found at a wider range of temperatures (−1–22°C vs 5–15°C). This is probably related both to the different oceanographic regions through which the fish migrated, as well as species differences in thermal range and vertical movements. Proportions of time that individual fish spent at different temperatures seemed to vary among oceanographic regions. Steelhead trout may descend to moderate depths (50 m) and not be limited to the top few metres, as had been believed. Japanese chum salmon may seek deep, cold waters as they encounter warm surface temperatures on their homeward migrations. Temperature data from all fish showed an initial period (4–21 days) of day and night temperatures near those of sea surface temperatures, suggesting a period of recuperation from tagging trauma. A period of tagging recuperation suggests that vertical movement data from short-term ultrasonic telemetry studies may not represent normal behaviour of fish. The considerable diurnal and shorter-term variation in ambient temperatures suggests that offshore ocean distribution may be linked more to prey distribution and foraging than to sea surface temperatures.

Climatic signals in the life histories of insects: the distribution and abundance of heather psyllids (Strophingia spp.) in the UK

1. The population density and age structure of two species of heather psyllid Strophingia ericae and Strophingia cinereae, feeding on Calluna vulgaris and Erica cinerea, respectively, were sampled using standardized methods at locations throughout Britain. Locations were chosen to represent the full latitudinal and altitudinal range of the host plants. 2. The paper explains how spatial variation in thermal environment, insect life‐history characteristics and physiology, and plant distribution, interact to provide the mechanisms that determine the range and abundance of Strophingia spp. 3. Strophingia ericae and S. cinereae, despite the similarity in the spatial distribution patterns of their host plants within Britain, display strongly contrasting geographical ranges and corresponding life‐history strategies. Strophingia ericae is found on its host plant throughout Britain but S. cinereae is restricted to low elevation sites south of the Mersey–Humber line and occupies only part of the latitudinal and altitudinal range of its host plant. There is no evidence to suggest that S. ericae has reached its potential altitudinal or latitudinal limit in the UK, even though its host plant appears to reach its altitudinal limit. 4. There was little difference in the ability of the two Strophingia spp. to survive short‐term exposure to temperatures as low as – 15 °C and low winter temperatures probably do not limit distribution in S. cinereae. 5. Population density of S. ericae was not related to altitude but showed a weak correlation with latitude. The spread of larval instars present at a site, measured as an index of instar homogeneity, was significantly correlated with a range of temperature related variables, of which May mean temperature and length of growing season above 3 °C (calculated using the Lennon and Turner climatic model) were the most significant. Factor analysis did not improve the level of correlation significantly above those obtained for single climatic variables. The data confirmed that S. ericae has a 1 year life cycle at the lowest elevations and a 2 year life cycle at the higher elevations. However, there was no evidence, as previously suggested, for an abrupt change from a one to a 2 year life cycle in S. ericae with increasing altitudes or latitudes. 6. By contrast with S. ericae, S. cinereae had an obligatory 1 year life cycle, its population decreased with altitude and the index of instar homogeneity showed little correlation with single temperature variables. Moreover, it occupied only part of the range of its host plant and its spatial distribution in the UK could be predicted with 96% accuracy using selected variables in discriminant analysis. 7. The life histories of the congeneric heather psyllids reflect adaptations that allow them to exploit host plants with different distributions in climatic and thereby geographical space. Strophingia ericae has the flexible life history that enables it to exploit C. vulgaris throughout its European boreal temperate range. Strophingia cinereae has a less flexible life history and is adapted for living on an oceanic temperate host. While the geographic ranges of the two Strophingia spp. overlap within the UK, the psyllids appear to respond differently to variation in their thermal environment.

Effects of Geographically Variable Thermal Environment on Bioenergetics of Mottled Rock Rattlesnakes

Geographic variation in thermal environment may significantly influence the energetics of ectotherms, and thus may serve as a mechanisms for geographic variation in growth and reproduction. Thermal environment affects body temperature (Tb) that, in turn, has consequences both for the amount of time available for surface activities such as foraging, and for physiological processes such as metabolism. I studied effects of differences in thermal environment on Tb), surface use, and resting metabolism of mottled rock rattlesnakes (Crotalus lepidus) from two populations (Boquillas: BOQ, and Grapevine Hills: GVH) in Big Bend National Park, Texas. Snakes in these populations differed in growth rate and adult body size, and these differences may be related to the influence of thermal environment on energetics. During summer months, operative environmental temperatures at BOQ were hotter than at GVH. Hotter BOQ environmental temperatures resulted in °64% less time available for diurnal surfaces use (e.g., foraging) at BOQ relative to GVH. Hotter BOQ environmental temperatures also constrained the average Tb of BOQ snakes at night to be from 2°C to 4.5°C hotter than GVH snakes during July and August. Despite hotter Tb, estimated resting metabolic expenditures of BOQ snakes during July and August were similar to estimated expenditures of GVH snakes because BOQ snakes had lower mass—specific metabolic rates. Results of this study were consistent with the hypothesis of greater energy limitation at BOQ, and underscored the importance of population—specific data for understanding geographic variation in energy acquisition and allocation.

Energy losses as a function of temperature during the development of Diadromus collaris and D. pulchellus, solitary endoparasites of Acrolepiopsis assectella (Lepidoptera: Plutellidae)

Using gravimetric and calorimetric measurements, we have studied the action of thermal environmental variations (from a 15–25°C thermoperiod to 20–30°C) on the total energy spent during the endoparasitic development of Diadromus pulchellus and D. collaris (Hymenoptera: Ichneumonidae) in the pupae of Acrolepiopsis assectella Z. (Hymenoptera: Plutellidae) to maintain their basal metabolism, activity and thermoregulation. These two Diadromus species expended an identical 24 h maintenance energy in the 15–25°C thermoperiod ( 0.24 cal 24 h for females and 0.26 cal 24 h for males). Maintenance energy in the 20–30°C thermoperiod was identical in males ( 0.38 cal 24 h ) and somewhat different in females (0.35 and 0.37 cal 24 h respectively). A 5°C temperature increase (15 to 20°C and 25 to 30°C) during the dark and light periods resulted in increased 24 h energy expenditures by both species, somewhat greater in D. pulchellus females.