scholarly journals The Oviposition Responses of Calandra Granaria Linn

1943 ◽  
Vol 20 (1) ◽  
pp. 35-42
Author(s):  
L. E. S. EASTHAM ◽  
SHELIA B. McCULLY
Keyword(s):  
Relative Humidity ◽  
Water Content ◽  
Low Temperatures ◽  
Egg Production ◽  
Oviposition Rate ◽  
Preoviposition Period ◽  
Dry Food ◽  
Food Grain ◽  
Length Of Life ◽  
Low Rate

1. The oviposition responses of Calandra granaria as manifested by the rate of oviposition, total eggs laid, length of life, length of life, length of ovipository life and length of preoviposition period, have been investigated under controlled conditions of temperature and saturation deficiency of air, grain having been acclimatized in its water content to the relative humidity of the air. 2. Calandra lives for a shorter time under high than under low temperatures but lays eggs at a greater rate, thus compensating for the shorter life. 3. There is evidence for the existence of an optimum saturation deficiency at each temperature for oviposition rate. 4. Weevils are shorter lived at high saturation deficiencies than they are at low. 5. The total number of eggs laid by weevils is smaller at high than at low saturation deficiencies of air. 6. Water content of the food grain contributes to these results in that dry food is conducive to low rate of oviposition, low total egg production and shorter life.

The effects of temperature and humidity on the oviposition rate of Tribolium castaneum (Hbst.) (Coleoptera, Tenebrionidae)

1962 ◽  
Vol 53 (2) ◽  
pp. 301-310 ◽  
Author(s):  
R. W. Howe
Keyword(s):  
Tribolium Castaneum ◽  
Low Temperatures ◽  
Adult Life ◽  
Oviposition Rate ◽  
Optimum Temperature ◽  
Preoviposition Period ◽  
Innate Capacity ◽  
Effects Of Temperature ◽  
Capacity For Increase ◽  
Coleoptera Tenebrionidae

The rate of oviposition of isolated pairs of Tribolium castaneum (Hbst.) on finely divided wheatfeed was measured over the entire adult life at 25°C. and 70 per cent. R.H. It was also measured over a period of seven weeks from the start of oviposition at 30 and 70 per cent. R.H. at 25, 30 and 35°C., respectively, at 70 per cent. R.H. only at 22·5, 27·5, 32·5 and 37·5°C. and at 2 per cent. R.H. at 30°C.At 25°C. and 70 per cent. R.H. each female laid, on the average, 360 eggs at the rate of 2·5 per day for about one hundred days and then at a decreasing rate for the next hundred days. When this experiment was repeated over a seven-week period, each female laid on average about 3 eggs per day. At 70 per cent. R.H., the optimum temperature for oviposition was about 32·5°C., at which about 11 eggs per day per female were laid over the seven-week period. These rates fell to just over 2 per day at 22·5°C. Only one egg was laid by 15 females at 20°C. At 37·5°C. the rate was about 10 eggs per day initially but it declined to about 3 per day by the end of seven weeks, whereas at lower temperatures the decline in laying was slight. Compared with 70 per cent. R.H., the oviposition rate at 30 per cent. R.H. was almost halved at 25°C., but was only slightly reduced at 35°C. At 30°C. and 2 per cent. R.H., females laid well, averaging over 4 eggs per female per day. The periodic provision of water for drinking at 25°C. and 30 per cent. R.H. depressed oviposition.The preoviposition period was 2 days at 37·5°C. and increased steadily at lower temperatures to 10 days at 22·5°C. It also varied more between females at low temperatures.The number of eggs recovered in this work was lower than the number obtained by Park & Frank (1948), who used considerably more food in their oviposition chambers. In this work, some eggs were eaten by the adult beetles. However, the innate capacity for increase of the species calculated on these data is extremely high, and could not be maintained for long because of the cannibalistic habits of this species.

Length of life, fecundity and the oviposition cycle in Anthrenus verbasci (L.) (Col., Dermestidae) as affected by adult diet

1961 ◽  
Vol 52 (3) ◽  
pp. 459-472 ◽  
Author(s):  
G. M. Blake
Keyword(s):  
Control Group ◽  
Sugar Solution ◽  
Male And Female ◽  
The Third ◽  
Preoviposition Period ◽  
Males And Females ◽  
Length Of Life ◽  
Active Adults ◽  
Adult Diet ◽  
Low Rate

A study has been made of the length of life, fecundity, oviposition and the effects upon them of adult nutrition in the varied carpet beetle, Anthrenus verbasci (L.).The length of the inactive (unmated) life for males and females at 20°C. and 70 per cent. R.H. was 7·5 and 7·7 days, respectively. This period, which is spent in the moulted last larval skin, decreased with rise in temperature, from a mean of 32·4 days at 10°C. to 3·8 days at 25°C. Humidity differences had relatively little effect.The effects of various diets on the length of life, oviposition cycle and fecundity of active adults were observed. The experimental diets were water, water with pollen, water with albumen, sugar solution, sugar solution with pollen, sugar solution with albumen, and the control group in which the beetles were deprived of food and water. The sugar solution was a mixture of equal parts of glucose, sucrose and fructose in water.There were no differences in length of life between male and female beetles (males 18·2–20·9 days, females 22·1–26·1 days) given water, water with pollen, water with albumen and those deprived of food and water. But there was an increase for both sexes when the beetles were given sugar solution, and a further increase, to a mean of 58·3 days for males and 69·5 for females at 20°C. and 70–90 per cent. R.H., when albumen was added to the sugar solution. However, although sugar solution with pollen increases still further the length of life of the males, that of the females was no different from what it was on sugar solution alone.The preoviposition period ranged from 3–14 days with a mode about the fourth day.The oviposition cycle consisted of three clearly denned peaks of oviposition on about the 6th, 12th and 17th days. There was a similar pattern in all the groups except that those given sugar solution continued to lay, at a low rate, after the end of the third peak.The fecundity of beetles deprived of food and water was 50·3 eggs; for beetles given water, water with albumen and water with pollen there was a significant decrease; for beetles given sugar solution there was an increase which became significant when pollen or albumen were given in addition to the sugar. Maximum fecundity occurred on a diet of sugar solution with albumen.There was significant correlation between length of life and weight on emergence for males given water, water with pollen, or water with albumen, and for females given water with pollen or water with albumen. There was significant correlation between fecundity and emergence weight for females deprived of food and water, given water alone and water with pollen.

Oviposition and length of adult life in Caryedon gonagra (F.) (Col., Bruchidae)

1965 ◽  
Vol 55 (4) ◽  
pp. 697-707 ◽  
Author(s):  
J. P. Cancela da Fonseca
Keyword(s):  
Relative Humidity ◽  
Adult Life ◽  
Continuous Darkness ◽  
Preoviposition Period ◽  
Important Pest ◽  
Full Complement ◽  
Single Mating ◽  
The Mean ◽  
Length Of Life ◽  
Sexually Mature

Oviposition and the length of adult life in the Bruchid beetle Caryedon gonagra (F.), an important pest of unshelled groundnuts (Arachis) in West Africa, were studied in continuous darkness in incubators at 30 and 40°C. at relative humidities of 50, 70 and 90 per cent., and at 45°C. and 70 per cent., and also under conditions of diurnal alternation of periods of light and darkness in a constant-temperature room at about 27·5°C. and 75 per cent. R.H. Newly emerged beetles were placed, singly (unmated or after a single mating) or in pairs, in tubes with 1–5 unshelled groundnuts. In addition, the influence of the absence of groundnuts was investigated.Length of life of the adults increased with decreasing temperature, increasing relative humidity, the absence of nuts (for females only) and the absence of mating (for females, and, in absence of nuts, for males). Adults survived for 3–4 days at 45°C. and 70 per cent. R.H. Optimum conditions are probably about 27·5—30°C. and 70—90 per cent. R.H., under which the adult length of life was about 21 days.The adults were sexually mature on emergence from the cocoons, and mating took place within 24 hours of emergence. Under the conditions of the experiments, the preoviposition period was between 24 and 48 hours. At 27·5 and 30°C., the mean length of the oviposition period (9—13 days) was only slightly influenced by relative humidity, being slightly shorter at the lowest R.H. (50%); an increase in temperature from 30 to 40°C. caused a marked reduction in the period.About 80 per cent, of the eggs were laid in crevices in the shell of the nut, where they are difficult to find. In the absence of nuts, the females laid readily between the cork and the glass and at the bottom of the tube.At 40°C., oviposition was inhibited at 50 and 70 per cent. R.H., but at 90 per cent. R.H. many eggs (but significantly fewer than at lower temperatures) were laid; the largest mean numbers (106–115) were laid at 27·5–30°C. and 70–90 per cent. R.H.; absence of nuts did not influence the numbers of eggs laid, but caused some irregularity in the oviposition pattern. More than one copulation appeared to be necessary for the female to lay a full complement of eggs.Under conditions of alternating periods of light and darkness, there was a daily rhythm of oviposition, with a strong correlation between numbers of eggs laid and the periods of darkness.The results are compared with those recorded in the literature.

scholarly journals Cold Wave-Induced Reductions in NDII and ChlRE for North-Western Pacific Mangroves Varies with Latitude and Climate History

2021 ◽  
Vol 13 (14) ◽  
pp. 2732
Author(s):  
Jonathan Peereman ◽  
J. Aaron Hogan ◽  
Teng-Chiu Lin
Keyword(s):  
Water Content ◽  
Geographic Distribution ◽  
Low Temperatures ◽  
Forest Canopy ◽  
Cold Wave ◽  
Mangrove Forests ◽  
Climate History ◽  
Wave Effects ◽  
Northern Pacific ◽  
Wave Induced

Mangrove forests growing at the poleward edges of their geographic distribution are occasionally subject to freezing (<0 °C) and cold wave (>0 °C) events. Cold wave effects on mangrove trees are well documented and adaptation to cold stress has been reported for local mangrove populations in the North Atlantic. However, there is less understanding of effects of cold waves on mangroves in the northern Pacific, especially at the regional scale. Moreover, it is unclear if cold tolerant mangrove species of North Asia display variation in resistance to cold temperatures across their geographic distribution. Using a cold wave event that occurred in January 2021, we evaluated the effects of low temperatures on vegetation index (VI) change (relative to a recent five-year baseline) for mangrove forests dominated by Kandelia obovata (Rhizophoraceae) and Avicennia marina (Acanthaceaee) at the northern edge of their geographical range. We used two VIs derived from Sentinel-2 imagery as indicators for canopy health: the normalized difference infrared index (NDII) and the chlorophyll red-edge index (ChlRE), which reflect forest canopy water content and chlorophyll concentration, respectively. We isolated the cold wave effects on the forest canopy from phenology (i.e., cold wave induced deviation from a five-year baseline) and used multiple linear regression to identify significant climatic predictors for the response of mangrove forest canopy VI change to low temperatures. For areas where the cold wave resulted in temperatures <10 °C, immediate decreases in both VIs were observed, and the VI difference relative to the baseline was generally greater at 30-days after the cold wave than when temperatures initially recovered to baseline values, showing a slight delay in VI response to cold wave-induced canopy damage. Furthermore, the two VIs did not respond consistently suggesting that cold-temperature induced changes in mangrove canopy chlorophyll and water content are affected independently or subject to differing physiological controls. Our results confirm that local baseline (i.e., recent past) climate predicts canopy resistance to cold wave damage across K. obovata stands in the northern Pacific, and in congruence with findings from New World mangroves, they imply geographic variation in mangrove leaf physiological resistance to cold for Northern Pacific mangroves.

The ecology of immature phases of trichostrongyle nematodes

Parasitology ◽  
1949 ◽  
Vol 39 (3-4) ◽  
pp. 274-280 ◽  
Author(s):  
H. D. Crofton
Keyword(s):  
Low Temperatures ◽  
Parasitic Disease ◽  
Larval Population ◽  
Rate Of Development ◽  
Pasture Contamination ◽  
Low Rate

Observations on the larvae of sheep trichostrongyles on hill pastures showed:1. A reduction in larval populations occurred when the ‘moving-flock’ type management was used. The large proportion of eggs passed in faeces is deposited on a part of the pasture where little or no grazing occurs.2. Local concentrations of larvae occurred on the grazed portions of a pasture when grazing was uneven. Thus, the apparent low rate of stocking on hill pastures does not give a true picture of the potential dangers of parasitic disease. Estimates of pasture contamination by Taylor's method of sampling were deceptively low.3. The number of larvae on grass blades was lowest when the grass was wet with dew. Sampling of pastures between 12 noon and 5 p.m g.m.t. gave maximal and most constant estimates.4. There was an increase in the number of larvae on a pasture during the warmer months of the year. While low temperatures prevent or delay hatching, the increase in population was not entirely due to the increased rate of development when temperature was high. The increase in numbers was partly due to an increase in the number of adult worms in the sheep hosts.5. Removal of sheep for 3 weeks reduced the number of larvae on a pasture. This reduction was not apparent, however, until after the first 12 days. After 3 weeks the pasture population was reduced by 55 %, while after 4 weeks (i.e. 7 days after the return of the sheep) the reduction was 90%. Two weeks later there was a small increase in the larval population, but this was again reduced with the onset of colder conditions.

Modeling Vapor Transport in a Hollow Fiber Membrane Humidifier Using ε-NTU Approach

2020 ◽  
Author(s):  
Hoang Nghia Vu ◽  
Xuan Linh Nguyen ◽  
Sangseok Yu
Keyword(s):  
Heat Transfer ◽  
Mass Transfer ◽  
Fuel Cell ◽  
Relative Humidity ◽  
Transfer Coefficient ◽  
Mass Transfer Coefficient ◽  
Water Content ◽  
Vapor Transport ◽  
Overall Mass Transfer Coefficient ◽  
Mass Exchanger

Abstract In a fuel cell vehicle, the water content of the gas supply within certain ranges plays a key role in improving the performance of a proton exchange membrane. The lower limit of water content in the air supply is to avoid the problem of drying-out, while the upper prevents flooding. Water management can be accomplished by a membrane humidifier which allows water vapor to permeate the mixture from the side having the higher water concentration, moving to the other side of the membrane. In this study, the variation in water content collected at the outlet of a membrane humidifier is investigated with a one-dimensional mass exchanger model and various operating variables. The vapor concentration of outlet flows is affected by operating temperature and relative humidity of the membrane humidifier. Relative humidity of the dry side at the point of outlet flow, to be supplied to the fuel cell module, is the key characteristic. The analogy of the effectiveness-NTU approach for heat transfer is used to analyze the characteristics of the mass exchanger. Mass flux through the membranes is estimated with an overall mass transfer coefficient which represents vapor transport characteristics moving through the membrane module. This coefficient has a similar role to the overall heat transfer coefficient in heat exchanger analysis. This parametric study is conducted to understand the effects of different variables. The Effectiveness-NTU methodology of mass transfer uses the overall mass transfer coefficient and the mass transfer rate, as evaluated experimentally. Simulink software is then employed to deliver outcomes of the model for different operating conditions.

scholarly journals Assessment of lettuce quality during storage at low relative humidity using Global Stability Index methodology

2012 ◽  
Vol 32 (2) ◽  
pp. 366-373 ◽  
Author(s):  
María Roberta Ansorena ◽  
María Victoria Agüero ◽  
María Grabriela Goñi ◽  
Sara Roura ◽  
Alejandra Ponce ◽  
...  
Keyword(s):  
Ascorbic Acid ◽  
Relative Humidity ◽  
Global Stability ◽  
Water Content ◽  
Relative Water Content ◽  
Storage Time ◽  
Stability Index ◽  
Total Chlorophyll ◽  
External Zone ◽  
Relative Water

During postharvest, lettuce is usually exposed to adverse conditions (e.g. low relative humidity) that reduce the vegetable quality. In order to evaluate its shelf life, a great number of quality attributes must be analyzed, which requires careful experimental design, and it is time consuming. In this study, the modified Global Stability Index method was applied to estimate the quality of butter lettuce at low relative humidity during storage discriminating three lettuce zones (internal, middle, and external). The results indicated that the most relevant attributes were: the external zone - relative water content, water content , ascorbic acid, and total mesophilic counts; middle zone - relative water content, water content, total chlorophyll, and ascorbic acid; internal zone - relative water content, bound water, water content, and total mesophilic counts. A mathematical model that takes into account the Global Stability Index and overall visual quality for each lettuce zone was proposed. Moreover, the Weibull distribution was applied to estimate the maximum vegetable storage time which was 5, 4, and 3 days for the internal, middle, and external zone, respectively. When analyzing the effect of storage time for each lettuce zone, all the indices evaluated in the external zone of lettuce presented significant differences (p < 0.05). For both, internal and middle zones, the attributes presented significant differences (p < 0.05), except for water content and total chlorophyll.

WATER RELATIONS OF ASEXUAL SPORES OF SPHAEROTHECA MACULARIS (WALLR. EX. FR.) COOKE AND ERYSIPHE POLYGONI DC.

1965 ◽  
Vol 11 (3) ◽  
pp. 531-538 ◽  
Author(s):  
J. S. Jhooty ◽  
W. E. McKeen
Keyword(s):  
Relative Humidity ◽  
Water Content ◽  
Osmotic Pressure ◽  
Water Relations ◽  
Erysiphe Polygoni ◽  
Significant Change ◽  
Sphaerotheca Macularis ◽  
Glass Surfaces

The conidia of Sphaerotheca macularis germinate best at a relative humidity (R.H.) of 99 and 100% on glass surfaces, and germination does not occur if the R.H. is below 93%. Conidia of Erysiphe polygoni DC. germinate at 3% R.H. The water content of conidia of S. macularis and E. polygoni is 53 and 69% respectively. The osmotic pressure of S. macularis conidia is about 18 atm and their density varies from 1.10 to 1.11 g/ml. There is no significant change in the diameter and length of the conidia during germination.

scholarly journals Basaltic stones with epilithic lichens as a novel substrate for an osmotolerant fungus, Aspergillus glaucus

2017 ◽  
Vol 52 (1) ◽  
Author(s):  
Isabella Grishkan ◽  
Marina Temina
Keyword(s):  
Relative Humidity ◽  
Water Activity ◽  
Low Temperatures ◽  
Water Regime ◽  
Storage Period ◽  
Cellular Mechanism ◽  
Nutrient Source ◽  
Nutrient Sources ◽  
Aspergillus Glaucus ◽  
Epilithic Lichens

<em>Aspergillus glaucus</em><span> is a fungus able to tolerate low water activity of the environment. Its dense growth and sporulation were found on basaltic stones with epilithic lichens after 14 years of storage at a temperature of 4–7°C and relative humidity of 14–18%. Dust and soil particles deposited on the lichen thalli and dissolved in the water condensed on the stones during the storage period, apparently served as a nutrient source for the fungus. Probably, strongly xeric water regime on basaltic stones suitable for <em>A. glaucus</em> did not allow mesophilic fungi to develop and prevented the xerotolerant fungus from competition with other microfungi for nutrient sources. It is also possible that specific cellular mechanism associated with the production of chaotropic compounds (such as glycerol) supported germination and development of <em>A. glaucus</em> at low temperatures, which were considered non-optimal for the fungus.</span>

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