Croissance, bilan d'energie et production d'eau metabolique chez la larve de Tineola bisselliella

1981 ◽  
Vol 59 (2) ◽  
pp. 297-304 ◽  
Author(s):  
G. Chauvin ◽  
A. Gueguen ◽  
G. Vannier
Keyword(s):  
Relative Humidity ◽  
Constant Temperature ◽  
Body Water ◽  
Body Tissue ◽  
Larval Life ◽  
Physiological Reactions ◽  
Silk Secretion ◽  
Metabolic Water ◽  
Tineola Bisselliella

The keratophagous larva Tineola bisselliella develops better in a dry than in a wet environment at the constant temperature of 20 °C. At 95% relative humidity (RH), mortality is higher than 80% and the larval life lasts up to 341 days. At 5% RH, mortality reaches only 30% and the larval life lasts only 216 days. The study of utilization of the energy contained in 3680 μg of food (mukrat hair) at 95% RH and then at 5% RH shows the physiological reactions of the larva when the RH is modified. At 5% RH, the larva ingest the 3680 μg of food in 17 days while they ingest the same amount in 10 days at 5% RH. For the same quantity of ingested energy, the energetic value lost by respiration and silk secretion are more important at 95% RH than at 5% RH. In a very wet environment, the energy lost in the feces is reduced. At 5% RH, the production of body tissue and the storage of the ingested energy are twice as high as those at 95% RG, in spite of a loss of water which may exceed 4 μg/h. The production of metabolic water allows the larva to keep constant its quantity of body water and does not prevent the storage of lipidic substances. The weight of metabolic water produced at 5% RH is evaluated at 33% of the weight of the ingested food.

scholarly journals Red flour beetle survival on different food items

2005 ◽  
Vol 2 (1) ◽  
pp. 33-36
Author(s):  
Baghdad Science Journal
Keyword(s):  
Life Cycle ◽  
Relative Humidity ◽  
Durum Wheat ◽  
Constant Temperature ◽  
Red Flour Beetle ◽  
Living Situation ◽  
Flour Beetle ◽  
Food Items

Studied red beetle life on each of the yen and wheat durum wheat, barley, corn, rice, chickpeas, ground peanuts and beans in Living situation constant temperature and relative humidity of 65% for a period of 66 days was the life cycle of the insect different from one substance to another ....

Memoirs: The Early Embryonic Development of Rhodnius Prolixus (Hemiptera, Heteroptera)

1935 ◽  
Vol s2-78 (309) ◽  
pp. 71-90
Author(s):  
HELEN MELLANBY
Keyword(s):  
Relative Humidity ◽  
Embryonic Development ◽  
Early Development ◽  
Constant Temperature ◽  
Germ Cells ◽  
Rhodnius Prolixus ◽  
Posterior Pole ◽  
Early Embryonic Development ◽  
Temperature And Humidity ◽  
Cent Relative Humidity

1. Eggs of Rhodnius prolixus were incubated at constant temperature and humidity (21° C. and 90 per cent, relative humidity). Eighty-five per cent, was the lowest record of the controls hatched successfully under these conditions. 2. The processes of maturation and fertilization were not studied. 3. Cleavage begins 12-13 hours after incubation. At 25 hours there are 32 nuclei. Yolk-cells are derived from cleavage nuclei, and they multiply by mitosis up to 50 hours. Blastoderm formation is complete after 55-60 hours of incubation. 4. The ventral embryonic rudiment is similar to that of many other insects. As soon as it is formed, germ-cells are budded off at the posterior pole of the egg. 5. The first stage in blastokinesis is fully described. 6. The formation of the mesoderm is by invagination and overgrowth. 7. The endoderm arises from two proliferating areas situated anteriorly and posteriorly. 8. Numerous cells are given off into the yolk during the early development of the embryo. There they disintegrate.

Comparative study of destructive, nondestructive, and numerical procedures for the determination of moisture dependent shear moduli in Scots pine wood

2021 ◽  
Vol 63 (11) ◽  
pp. 1063-1069
Author(s):  
Murat Aydın ◽  
Hasan Hüseyin Ciritcioğlu
Keyword(s):  
Finite Element ◽  
Relative Humidity ◽  
Shear Modulus ◽  
Scots Pine ◽  
Constant Temperature ◽  
Transverse Wave ◽  
Element Analysis ◽  
Shear Moduli ◽  
Principal Axes ◽  
Static Shear

Abstract In this study, moisture dependent shear moduli in Scots pine (Pinus sylvestris L.) wood were determined by a 45° off-axis (longitudinal, radial, and tangential) compression test and ultrasonic transverse wave propagation. Finite element modeling was performed to ascertain how the results agree with the numerical method. Ultrasonic transverse wave velocities on the LR, LT, and RT planes were decreased from 1347, 1323, and 589 m × s-1 to 1286, 1269, and 561 m × s-1 when relative humidity increased from 45 % to 85 % at a constant temperature of 20 ± 1 °C, respectively. The dynamic and static shear modulus on the LR, LT, and RT planes were decreased from 988, 953, and 189, and 966, 914, and 182 MPa to 927, 903, and 176, and 845, 784, and 154 MPa when relative humidity increased from 45 % to 85 % at a constant temperature of 20 ± 1 °C, respectively. Therefore, both velocity and modulus values at all principal axes and planes were decreased with an increase in moisture. Maximum (15.2 %) and minimum (2.3 %) differences between dynamic and the static shear modulus were observed for GLT at 85 % and GLR at 45 % relative humidity, respectively. Coefficients of determinations between the dynamic and static shear moduli were ranged from 0.68 (GLR at 65 % RH) to 0.97 (GLR at 85 % RH). Finite element analysis, only for 65 % RH values, was performed using Solid 45 element, and, according to results, load-deformation curves created by linear orthotropic material properties, are well-matched with the static curves.

Factors Affecting Toxicity and Translocation of Glyphosate in Cotton(Gossypium hirsutum)

Weed Science ◽  
1978 ◽  
Vol 26 (5) ◽  
pp. 509-513 ◽  
Author(s):  
G. D. Wills
Keyword(s):  
Relative Humidity ◽  
Gossypium Hirsutum ◽  
Constant Temperature ◽  
Environmental Conditions ◽  
Plant Tissue ◽  
Fold Increase ◽  
Herbicide Application ◽  
Factors Affecting ◽  
Treated Area ◽  
Lower Stem

Toxicity of nonradiolabeled and translocation of14C-labeled glyphosate [N-(phosphonomethyl)glycine] in cotton(Gossypium hirsutumL.) were evaluated under different environmental conditions as affected by surfactant and by the maturity of the plant tissue at the place of herbicide application. Toxicity was affected primarily by temperature with 21 to 40% greater cotton injury at 25 C than at 35 C. The addition of surfactant often increased toxicity under environmental conditions where toxicity was initially low. Absorption and translocation of14C was affected primarily by relative humidity (RH). At constant temperature and rate of surfactant, an increase in RH from 40 to 100% resulted in a 3- to 6-fold increase in translocation of14C. Autoradiograms indicated that the movement of the14C-label was primarily into leaves above the treated area. Translocation of14C was significantly greater following application to the mature lower stem than to the mature lower leaves or to immature upper stem or leaves of cotton.

Wood Fracture Pattern during the Water Adsorption Process

Holzforschung ◽  
2003 ◽  
Vol 57 (6) ◽  
pp. 639-643 ◽  
Author(s):  
W. Liyu ◽  
L. Zhenyou ◽  
Z. Guangjie
Keyword(s):  
Fracture Toughness ◽  
Relative Humidity ◽  
Moisture Content ◽  
Constant Temperature ◽  
Maximum Load ◽  
Fracture Pattern ◽  
Propagation Path ◽  
Betula Platyphylla ◽  
Moisture Adsorption ◽  
Pinus Bungeana

Summary A research program was conducted to investigate the effect of water transition on wood fracture properties, focusing on fracture behavior and patterns with different crack orientations of Betula platyphylla Suk. and Pinus bungeana in three different moisture adsorption processes. At a constant temperature of 20°C, three levels of relative humidity were considered: 66%, 82% and 100%. The results indicated that moisture content did not influence the crack propagation path, while specimen crack orientation did. With longer moisture adsorption times, the time needed to reach the maximum load from the critical load also grew; this is because below the fiber saturation point, from excessive dryness to a certain moisture content, the cell wall becomes less brittle and the toughness is enhanced. At 20°C constant temperature, the fracture toughness gradually increased from oven-dry state adsorbing moisture to 82% relative humidity, but decreased from 82% to 100% relative humidity. Within a tree species, fracture toughness depended on specimen type. The fracture toughness of LT specimens was by far higher than that of TL and TR specimens. The LT specimen fracture toughness of Betula platyphylla Suk. was comparable to that of Pinus bungeana.

Technique for evaluating the potential for growth of shoot and root buds of white clover (Trifolium repens)

1992 ◽  
Vol 119 (2) ◽  
pp. 179-183 ◽  
Author(s):  
P. C. D. Newton ◽  
M. J. M. Hay
Keyword(s):  
Relative Humidity ◽  
Constant Temperature ◽  
White Clover ◽  
Environmental Conditions ◽  
Trifolium Repens ◽  
Experimental Results ◽  
Root Primordia ◽  
Primary Interest ◽  
Root Buds ◽  
Subtending Leaves

SUMMARYAn assay was developed for assessing the potential for growth of shoot and root buds of white clover. This paper describes the technique and the experimental results on which it was based. The assay involved the incubation of nodes under standard conditions and the monitoring of bud activity at the nodes. Shoot buds were of primary interest but the assay was also used to investigate the activity of root primordia. Correlative influences were reduced by separating individual nodes and by removal of their subtending leaves and petioles. The optimal environmental conditions for incubation were: a constant temperature of 20 °C, a 24 h photoperiod of low irradiance (4 W/m2) and a high relative humidity (≥ 90%). The technique proved suitable for the monthly screening of 1000–2000 nodes sampled from field populations of white clover.

Diurnal Activity in the Dusky Cockroach, Ectobius lapponicus L. (Blattodea)

1971 ◽  
Vol 2 (2) ◽  
pp. 132-138 ◽  
Author(s):  
Hans Dreisig
Keyword(s):  
Relative Humidity ◽  
Constant Temperature ◽  
Low Temperatures ◽  
Laboratory Experiments ◽  
Dark Period ◽  
Light Period ◽  
Total Darkness ◽  
Diurnal Activity ◽  
Males And Females ◽  
The Difference

AbstractThe activity of the cockroach Ectobius lapponicus was found to differ in males and females in the field, the males being active during the afternoon, the females after sunset. The difference was thought to be due to an inhibition by low temperatures in the males, displacing the activity towards an earlier period of the day. This is in accordance with a theory concerning sensitization, and different thresholds of release dependent on light and temperature as established for the stridulation in Orthoptera Ensifera and the locomotion in a domestic cockroach. A relationship between the amount of activity and the relative humidity was found in the nymphs. Laboratory experiments showed that the activity at constant temperature was released by a change from light to darkness. If low temperatures were applied during the dark period, the activity was displaced to the latter half of the light period. The influence of illumination on the activity was investigated, a faint illumination being more favourable than total darkness.

Sporulation of Pleurotus ostreatus

1972 ◽  
Vol 50 (11) ◽  
pp. 2111-2115 ◽  
Author(s):  
F. I. McCracken
Keyword(s):  
Relative Humidity ◽  
Constant Temperature ◽  
Pleurotus Ostreatus ◽  
Late Summer ◽  
Spore Production ◽  
Late Afternoon ◽  
Late Fall

In 1968–1970 Pleurotus ostreatus sporophores produced most spores in the afternoon during late fall and winter, when production increased with daily increases in temperature and decreases in relative humidity. In late summer and fall, production peaked between late afternoon and midnight. Diurnal production patterns did not occur in the laboratory at constant temperature, light, and relative humidity. At 85–95% relative humidity, sporulation increased exponentially with temperatures from 1 to 25C. Production ceased at less than 1C and above 27–30C. Alternating temperatures of 5 and 25C at 12-h intervals resulted in corresponding periods of high and low spore production which continued for up to 24 h after treatment ceased. At 17C, sporulation was higher at 30% relative humidity than at 90% relative humidity. Sporulation was unaffected by alternating light and darkness at constant temperature and relative humidity.

scholarly journals Cuticular Permeability, Percent Body Water Loss, and Relative Humidity Equilibria Comparisons of Four Termite Species

2019 ◽  
Vol 19 (5) ◽  
Author(s):  
John Zukowski ◽  
Nan-Yao Su
Keyword(s):  
Relative Humidity ◽  
Water Loss ◽  
Water Retention ◽  
Loss Rate ◽  
Physical Structure ◽  
Body Water ◽  
Coptotermes Formosanus ◽  
Termite Species ◽  
Water Loss Rate ◽  
Cuticular Permeability

Abstract This study compared percentage of total body water (%TBW), water loss rate under desiccative conditions, and cuticular permeability (CP) of four termite species (Order: Blattodea, Infraorder: Isoptera) from different habitats, including one subterranean termite, Coptotermes formosanus Shiraki (Blattodea: Rhinotermitidae), one dampwood termite, Neotermes jouteli (Banks) (Blattodea: Kalotermitidae), one ‘wetwood’ termite, Cryptotermes cavifrons Banks (Blattodea: Kalotermitidae), and one drywood termite, Cryptotermes brevis Walker (Blattodea: Kalotermitidae). There was no consistent pattern associated with the habitat relative humidity (RH) levels and the %TBW among the four termite species tested. Because C. formosanus forage for food, its lowest %TBW may be due to its ability to access water sources, and its need to be more mobile than kalotermitids that remain in wood. Body water loss rate and CP were lower for xeric species such as Cr. brevis than hydric species such as N. jouteli. An RH equilibrium represents the capacity of termite water retention mechanisms that may include the physical structure of cuticular layers, behavioral manipulation of natural openings, and physiological means. As with water loss rate and CP data, RH equilibria were lower for xeric species such as Cr. brevis than hydric species such as N. jouteli. Moreover, RH equilibria for dead individuals of the four termite species were significantly higher than those of live individuals, indicating dead termites lost more water after losing their physiological and behavioral means of retaining water. RH equilibria represent termites’ capability in water retention, and there is a strong linear relationship between RH equilibria and CP values. Hence, RH equilibria may offer simpler alternatives to CP estimates.

The effect of low relative humidity at constant temperature on pollen asthma

1935 ◽  
Vol 6 (2) ◽  
pp. 111-122 ◽  
Author(s):  
B.Z. Rappaport ◽  
Tell Nelson ◽  
William H. Welker
Keyword(s):  
Relative Humidity ◽  
Constant Temperature
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