Effects of Temperature and Humidity on the Metabolism of the Fasting Bed-Bug (Cimex lectularius), Hemiptera

Parasitology ◽  
1932 ◽  
Vol 24 (3) ◽  
pp. 419-428 ◽  
Author(s):  
Kenneth Mellanby
Keyword(s):  
Dry Matter ◽  
Moist Air ◽  
Bed Bugs ◽  
Bed Bug ◽  
Dry Air ◽  
Loss Of Weight ◽  
Cent Relative Humidity ◽  
Effects Of Temperature ◽  
Rate Of Evaporation ◽  
Food Reserves

A method is described by which individual bed-bugs, weighing only 5 mg., can be accurately weighed, and their rate of loss of weight measured during starvation.Fasting bed-bugs were kept for various periods at five temperatures, ranging from 8° C. to 37° C., and at four humidities—0, 30, 60 and 90 per cent. relative humidity—at each temperature. Analysis after the experiments showed that the same amounts of food reserves were used up at each humidity for one temperature, and, as more water was evaporated from those kept in dry air than from those in moist, the proportion of dry matter rose most rapidly in dry air. Protein was the main food reserve used.Although the rate of loss of water was greatest in dry air, the rate of loss was relatively greater in moist air when the saturation deficiencies are compared. It appears that the insects conserve their water in dry air, but their surface area being so great in comparison with their volume, they cannot prevent all evaporation. This evaporation is at a rate nearly proportional to the saturation deficiency of the air.In moist air water appears to be evaporated freely. It is suggested that the spiracles are kept closed more in dry air and less in moist, which accounts for the fact that the rate of evaporation is proportionately greatest in moist air.A comparison is made between the results obtained with Cimex and Rhodnius.

scholarly journals The effect of atmospheric humidity on the metabolism of the fasting mealworm ( Tenebrio molitor L., Coleoptera)

1932 ◽  
Vol 111 (772) ◽  
pp. 376-390 ◽  
Keyword(s):  
Relative Humidity ◽  
Dry Matter ◽  
Total Water ◽  
Moist Air ◽  
Atmospheric Humidity ◽  
Dry Air ◽  
Two Temperatures ◽  
The Difference ◽  
Food Reserves ◽  
Metabolic Water

Previous work has shown that fasting mealworms will live at room tempera­ture for two hundred days, and even at 30°C. they usually live for over a month. During the first two days of starvation the mealworms are restless, and they pass a certain amount of excrement. After this they lie quite still, and pass extremely little excreta. The loss in weight of starving mealworms is different in dry and moist air at one temperature, or in air with the same relative humidity at two temperatures. At 23° C. the mealworms evidently regulate their metabolism, because while they lose weight at different rates in air of various relative humidities, yet they keep the ratio of dry matter to water in their bodies constant (Buxton, 1930). In carrying this work further, I have attempted to find whether the rate at which fasting mealworms evaporate water is proportional at any temperature to the saturation deficiency of the air. Now the fasting mealworm not only evaporates water present in its body at the start of the experiment, but also considerable quantities of water produced by the metabolism of food reserves during starvation. We can estimate the amount of water present in the mealworms at the start of starvation, and can find how much is left at the end of the experiment; the difference represents part of the total water evaporated. But this method does not indicate any metabolic water which is produced and also evaporated during starvation. If one wishes to know the total water evaporated, it can be collected in a stream of air, or else the loss of food reserves must be estimated and the metabolic water produced calculated from these results. I preferred to use the second method, as it is not easy to measure the actual amount of water given off by insects except into dry air.

scholarly journals The Influence of Starvation on the Thermal Death-Point on Insects

1934 ◽  
Vol 11 (1) ◽  
pp. 48-53
Author(s):  
MELLANBY KENNETH
Keyword(s):  
High Temperatures ◽  
Moist Air ◽  
Dry Air ◽  
Pediculus Humanus ◽  
Thermal Death ◽  
Thermal Death Point ◽  
Food Reserves

Experiments are described in which newly hatched larval lice (Pediculus humanus corporis) and adult C. fatigans were exposed to high temperatures. The humidity was controlled, and the exposures lasted for either 1 or 24 hours. Larval lice, whether fed or unfed, withstood 46.5° C. for 1 hour, while the Culex were much less resistant--they only withstood a temperature of 39° C. The humidity of the air did not affect these results. When exposed for 24 hours, larval lice which had fed withstood 38° C. in moist air. They only withstood 33° C. in dry air, as they were killed by desiccation at higher temperatures. Mosquitoes (C. fatigans) which had gorged gave similar results. They survived 37° C. for 24 hours in moist air, and only 32° C. in dry. Unfed lice or mosquitoes behaved differently, as they could not withstand such high temperatures for periods of 24 hours. This was because they had small food reserves, and at high temperatures their rate of metabolism was so increased that they died of starvation.

The Relation of Adult Rhodnius prolixus (Reduviidae, Rhynchota) to Atmospheric Humidity

Parasitology ◽  
1932 ◽  
Vol 24 (3) ◽  
pp. 429-439 ◽  
Author(s):  
P. A. Buxton
Keyword(s):  
Experimental Study ◽  
Body Fluid ◽  
Dry Matter ◽  
The Body ◽  
Normal Male ◽  
Atmospheric Humidity ◽  
Solid Matter ◽  
Food Material ◽  
Dry Air ◽  
Cent Relative Humidity

1. The paper describes an experimental study on the effect of atmospheric humidity upon Rhadnius. The work was carried out on fasting males of known age, kept at 23° C. at different relative humidities; the proportion of water was determined after the lapse of definite periods of time. The normal male contains 30 per cent. of dry matter.2. Taking the results after 42 days' starvation, at 30, 60 and 90 per cent. humidity, the weight of each group of bugs has fallen to 50 per cent. of what it was at the start of the experiment. Those kept in damp air have lost dry matter and water in the same proportion, so that the percentage of dry matter after starvation is still 30 per cent. of the total weight. Those kept in drier air lose more water but oxidise less dry material, so that the proportion of solids rises during starvation: in those kept at 30 per cent. relative humidity the proportion of solids rises to 39 per cent. The figures for insects kept at 0 per cent. humidity are consistent, but it is not possible to obtain them beyond the 32nd day.3. Death is probably due to a rise in the concentration of the body fluid and not to the exhaustion of food material. This is shown by the fact that the exhaustion of solid matter is actually less in dry air than in moist, though mortality is only observed among the bugs kept in dry air.

Effects of Temperature and Humidity of Inhaled Air on the Concentration of Ethanol in a Man's Exhaled Breath

1982 ◽  
Vol 63 (5) ◽  
pp. 441-445 ◽  
Author(s):  
A. W. Jones
Keyword(s):  
Ethanol Concentration ◽  
Ethanol Metabolism ◽  
Gas Liquid Chromatography ◽  
Exhaled Breath ◽  
Upper Respiratory Tract ◽  
Moist Air ◽  
Dry Air ◽  
Temperature And Humidity ◽  
Upper Respiratory ◽  
Effects Of Temperature

1. Ten healthy men each drank a moderate dose of ethanol in experiments to test if the temperature and moisture content of inhaled air could alter the concentration of ethanol in exhaled breath. 2. They breathed air at various temperatures and relative humidities (RH) for about 1 min before the concentration of ethanol and the temperature of end-expired breath were determined. Control breaths were analysed after the same men breathed ordinary room air (23°C, 55% RH). All tests were made during the postabsorptive phase of ethanol metabolism and the breath samples were analysed by gas-liquid chromatography. 3. When the men breathed cold dry air (5°C, 0% RH), the expired ethanol concentration decreased by 9·6 ± 0·69% (mean ± se) and breath temperature dropped by 1·40 ± 0·08°C. Cold moist air (5°C, 100% RH) decreased breath ethanol concentration by 6·4 ± 1·02% and breath temperature dropped by 1·1 ± 0·07°C. With hot dry air (80°C, 0% RH) as the breathing medium the concentration of ethanol was lowered by 4·3 ± 1·27% but expired breath temperatures were unchanged from the control tests. On breathing hot moist air (50°C, 100% RH), breath ethanol concentrations decreased by 10·3 ± 0·59%, even though breath temperatures rose by 1·8 ± 0·14°C above that of the controls. 4. Ethanol dissolves in the watery mucous membrane of the upper respiratory tract and can equilibrate with inhaled and exhaled air. It seems likely that during exchanges of heat and water vapour between respired air and the mucus, which largely depends on the temperature and humidity of inhaled air, the equilibrium of ethanol at the breath/mucus interface becomes disrupted. This leads to changes in the concentration of ethanol in expired air.

On the Behaviour of Wireworms of the Genus Agriotes Esch. (Coleoptera, Elateridae)

1943 ◽  
Vol 20 (1) ◽  
pp. 43-53
Author(s):  
A. D. LEES
Keyword(s):  
Water Loss ◽  
The Other ◽  
Sudden Increase ◽  
Great Activity ◽  
Moist Air ◽  
Steep Gradient ◽  
Dry Air ◽  
Constant Rate ◽  
Rate Of Evaporation ◽  
Humidity Range

1. The general humidity behaviour, the humidity receptors and the orientation mechanisms have been studied in the larvae of Agriotes. 2. Wireworms avoid dry air, the intensity of avoidance being greatest when the alternatives are close to saturation . Within this humidity range a difference of 7.5 % R.H. in the alternative chamber (at 17 ° C.) is sufficient to ensure the successful avoidance of the lower humidity by nearly every individual, while statistically significant reactions are obtained with differences as small as 0.5 % R.H. At lower ranges of humidity the same differences yield progressively less intense reactions; at low humidities the response is entirely eliminated. 3. The intensity of the reaction is in better accord with the humidity differences when these are expressed as saturation deficiencies rather than as relative humidities. This suggests that the reaction is initiated by the evaporation of water (‘evapori-meter’ receptor) and not by the operation of receptors which function hygrometrically (‘hygrometer’ receptors). 4. The humidity ‘receptors’ lie on the head. Amputation experiments indicate that the relevant sites of evaporation are distributed between the antennae, maxillary and labial palps; the structure of these appendages is compatible with such a function;- on the other hand, sensilla which might conceivably have a hygroscopic function are absent. 5. Orientation is achieved by the operation of two mechanisms. First, larvae are more active in dry than in moist air (low hygro-kinesis); secondly, larvae show a directed response to low humidities (klinotaxis); this is displayed as a powerful backward recoil if the wireworm crosses a steep gradient from moist into dry air. No tropo-tactic component is involved. The failure of the reaction at low humidities is explained by the great activity of the larvae which interferes with the operation of the klino-tactic mechanism. It is suggested that the kinesis is maintained by a relatively constant rate of water loss from the head appendages, while the klino-taxis is initiated by any sudden increase in the rate of evaporation. 6. The behaviour can readily be correlated with the humidity conditions prevailing in the soil; the necessity for such a sensitive response is possibly dictated by the permeability of the cuticle which renders wireworms peculiarly liable to water loss in unsaturated atmospheres.

scholarly journals Post-Plasma Catalysis for Trichloroethylene Abatement with Ce-Doped Birnessite Downstream DC Corona Discharge Reactor

Catalysts ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 946
Author(s):  
Grêce Abdallah ◽  
Jean-Marc Giraudon ◽  
Rim Bitar ◽  
Nathalie De Geyter ◽  
Rino Morent ◽  
...  
Keyword(s):  
Corona Discharge ◽  
Active Oxygen Species ◽  
Surface Acidity ◽  
Good Stability ◽  
Ozone Decomposition ◽  
Moist Air ◽  
Plasma Catalysis ◽  
Dry Air ◽  
Water Tolerance ◽  
By Products

Trichloroethylene (TCE) removal was investigated in a post-plasma catalysis (PPC) configuration in nearly dry air (RH = 0.7%) and moist air (RH = 15%), using, for non-thermal plasma (NTP), a 10-pin-to-plate negative DC corona discharge and, for PPC, Ce0.01Mn as a catalyst, calcined at 400 °C (Ce0.01Mn-400) or treated with nitric acid (Ce0.01Mn-AT). One of the key points was to take advantage of the ozone emitted from NTP as a potential source of active oxygen species for further oxidation, at a very low temperature (100 °C), of untreated TCE and of potential gaseous hazardous by-products from the NTP. The plasma-assisted Ce0.01Mn-AT catalyst presented the best CO2 yield in dry air, with minimization of the formation of gaseous chlorinated by-products. This result was attributed to the high level of oxygen vacancies with a higher amount of Mn3+, improved specific surface area and strong surface acidity. These features also allow the promotion of ozone decomposition efficiency. Both catalysts exhibited good stability towards chlorine. Ce0.01Mn-AT tested in moist air (RH = 15%) showed good stability as a function of time, indicating good water tolerance also.

Transport properties of real moist air, dry air, steam, and water

2021 ◽  
pp. 1-9
Author(s):  
Sebastian Herrmann ◽  
Hans-Joachim Kretzschmar ◽  
Vikrant C. Aute ◽  
Donald P. Gatley ◽  
Eckhard Vogel
Keyword(s):  
Transport Properties ◽  
Moist Air ◽  
Dry Air

scholarly journals Widespread Mutations in Voltage-Gated Sodium Channel Gene of Cimex lectularius (Hemiptera: Cimicidae) Populations in Paris

2021 ◽  
Vol 18 (2) ◽  
pp. 407
Author(s):  
Mohammad Akhoundi ◽  
Dahlia Chebbah ◽  
Denis Sereno ◽  
Anthony Marteau ◽  
Julie Jan ◽  
...  
Keyword(s):  
Single Point ◽  
Cimex Lectularius ◽  
Single Point Mutation ◽  
Homozygous Mutation ◽  
Knockdown Resistance ◽  
Bed Bugs ◽  
Bed Bug ◽  
Channel Gene ◽  
Blood Sucking ◽  
The Status

Bed bugs, Cimex lectularius and C. hemipterus, are common blood-sucking ectoparasites of humans with a large geographical distribution, worldwide. In France, little is known about the status of bed bugs’ infestation and their resistance to insecticides, particularly, pyrethroids. Here, we aimed to find mutations in the kdr gene, known to be involved in resistance to insecticides. We gathered bed bugs from various infested locations, including 17 private houses, 12 HLM building complex, 29 apartments, 2 EHPAD, and 2 immigrants’ residences. A total of 1211 bed bugs were collected and morphologically identified as C. lectularius. Two fragments of the kdr gene, encompassing codons V419L and L925I, were successfully amplified for 156 specimens. We recorded sense mutation in the first amplified fragment (kdr1) in 89 out of 156 (57%) samples, in which in 61 out of 89 (68.5%) sequences, a change of valine (V) into leucine (L) V419L was observed. Within the second fragment (kdr2), a homozygous mutation was recorded in 73 out of 156 (46.7%) specimens at the codon 925. At this position, 43 out of 73 (58.9%) specimens had a sense mutation leading to the replacement of leucine (L) by isoleucine (I). Among 162 mutant sequences analyzed (89 for the kdr1 fragment and 73 for the kdr2 one), we detected single point mutation in 26.6%, while 73.4% presented the mutation in both kdr1 and kdr2 fragments. All modifications recorded in bed bug populations of Paris are described to be involved in the knockdown resistance (kdr) against pyrethroids.

scholarly journals A Study of Moist Air Condensation Characteristics in a Transonic Flow System

Energies ◽  
2021 ◽  
Vol 14 (13) ◽  
pp. 4052
Author(s):  
Jie Wang ◽  
Hongfang Gu
Keyword(s):  
Mach Number ◽  
Relative Humidity ◽  
Transonic Flow ◽  
Flow System ◽  
Plane Surface ◽  
Droplet Growth ◽  
Moist Air ◽  
Dry Air ◽  
Hydraulic Equipment ◽  
Non Equilibrium

When water vapor in moist air reaches supersaturation in a transonic flow system, non-equilibrium condensation forms a large number of droplets which may adversely affect the operation of some thermal-hydraulic equipment. For a better understanding of this non-equilibrium condensing phenomenon, a numerical model is applied to analyze moist air condensation in a transonic flow system by using the theory of nucleation and droplet growth. The Benson model is adopted to correct the liquid-plane surface tension equation for realistic results. The results show that the distributions of pressure, temperature and Mach number in moist air are significantly different from those in dry air. The dry air model exaggerates the Mach number by 19% and reduces both the pressure and the temperature by 34% at the nozzle exit as compared with the moist air model. At a Laval nozzle, for example, the nucleation rate, droplet number and condensation rate increase significantly with increasing relative humidity. The results also reveal the fact that the number of condensate droplets increases rapidly when moist air reaches 60% relative humidity. These findings provide a fundamental approach to account for the effect of condensate droplet formation on moist gas in a transonic flow system.

The Behavioral Response to Heat in the Common Bed Bug,Cimex lectularius (Hemiptera: Cimicidae)

2021 ◽  
Author(s):  
Raymond Berry
Keyword(s):  
Petri Dish ◽  
Cimex Lectularius ◽  
Bed Bugs ◽  
Bed Bug ◽  
Host Interaction ◽  
Video Images ◽  
Spherical Ball ◽  
The Common ◽  
Vertebrate Hosts

AbstractThe bed bug, Cimex lectularius L., is a common ectoparasite found to live among its vertebrate hosts. Antennal segments in bugs are critical for sensing multiple cues in the environment for survival. To determine whether the thermo receptors of bed bugs are located on their antennae; innovative bioassays were created to observe the choice between heated and unheated stimuli and to characterize the response of bugs to a heat source. Additionally, the effect of complete antenectomized segments on heat detection were evaluated. Heat, carbon dioxide, and moisture are cues that are found to activate bed bug behavior; a temperature at 38°C was used to assess the direction/degree at which the insect reacts to the change in distance from said stimulus. Using a lightweight spherical ball suspended by air through a vacuum tube, bed bugs and other insects are able to move in 360° while on a stationary point. Noldus EthoVision XT was used to capture video images and to track the bed bugs during 5-min bioassays. A bioassay was created using four Petri dish arenas to observe bed bug attraction to heat based on antennae segments at 40°C. The purpose of this study was to evaluate the effects of heat on complete antenectomized segments of the antennae. The results in this experiment suggest that bed bugs detect and are attracted to heat modulated by nutritional status. Learning the involvement of antennae segments in heat detection will help identify the location and role of thermoreceptors for bed bug host interaction.

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