Influence of Humidity on Mortality and Rate of Development of Immature Stages of the Grain-Infesting Mite Tyrophagus castellanii (Hirst) (Acarina: Acaridae) Reared on Mould Cultures

1958 ◽  
Vol 90 (12) ◽  
pp. 721-724 ◽  
Author(s):  
I. Rivard
Keyword(s):  
Direct Effect ◽  
Constant Temperature ◽  
Immature Stages ◽  
Food Material ◽  
Predator Prey ◽  
Rate Of Development ◽  
Fresh Food ◽  
Temperature And Humidity

It was observed that populations of Tyrophagus castellanii (Hirst) reared on cereal flakes and yeast for studies of predator-prey interactions were feeding on moulds rather than on the food material, and that an increase in humidity increased their rates of development. To discover whether this was caused by the direct effect of humidity on the mites or by a greater supply of fresh food brought about by an increase in humidity, rearings were made with a technique developed by Rivard (1958). The mites were reared exclusively on mould cultures under controlled temperature and humidity conditions. It was also possible with this technique to regdate modd growth to some extent, so that a supply of fresh food was always available to the mites. This is a report on the influence of various humidities on mortality and rate of development of the immature stages of T. castellanii at a constant temperature.

INFLUENCE OF TEMPERATURE AND HUMIDITY ON MORTALITY AND RATE OF DEVELOPMENT OF IMMATURE STAGES OF THE MITE TYROPHAGUS PUTRESCENTIAE (SCHRANK) (ACARINA: ACARIDAE) REARED ON MOLD CULTURES

1961 ◽  
Vol 39 (4) ◽  
pp. 419-426 ◽  
Author(s):  
I. Rivard
Keyword(s):  
Sex Ratio ◽  
Indirect Effect ◽  
Food Products ◽  
Immature Stages ◽  
Direct Influence ◽  
Tyrophagus Putrescentiae ◽  
Rate Of Development ◽  
Influence Of Temperature ◽  
Temperature And Humidity ◽  
Two Factors

Tyrophagus putrescentiae (Schrank), a mite that infests stored food products, was reared individually on mold cultures at all combinations of five temperatures and four humidities. Mortality during immature stages was lowest at 72.5° F and 80% to 90% R.H. Development was usually accelerated by an increase in either of these two factors. Temperature and humidity had a direct influence on mortality and rate of development, but humidity also had an indirect effect by affecting the mold on which the mite feeds. Adults obtained at 70% R.H. were usually relatively small in size. Sex ratio of the adults was approximately one to one; the males developed faster than the females.

Influence of Humidity on Longevity, Fecundity, and Rate of Increase of the Grain-infesting Mite Tyrophagus castellanii (Hirst) (Acarina: Acaridae) Reared on Mould Cultures

1959 ◽  
Vol 91 (1) ◽  
pp. 31-35 ◽  
Author(s):  
I. Rivard
Keyword(s):  
Constant Temperature ◽  
Immature Stages ◽  
Rate Of Development ◽  
Rate Of Increase ◽  
Innate Capacity

Results of an experiment reported previously (Rivard, 1958a) showed the influence of various humidities on mortality and rate of development of the immature stages of Tyrophagus castellanii (Hirst)reared on mould cultures at a constant temperature. Results of an experiment on the influence of humidity on the longevity and fecundity of the adult mites are reported in the present paper. Information gathered from both studies is used to calculate the innate capacity of the species for increase at different humidities.

The Role of Predation in Determining Traits of Aedes aegypti (Diptera: Culicidae) and Infection With Zika Virus

2021 ◽  
Author(s):  
Shawna Bellamy ◽  
Barry W Alto
Keyword(s):  
Aedes Aegypti ◽  
Zika Virus ◽  
Life History Traits ◽  
Immature Stages ◽  
Direct Effects ◽  
Infected Blood ◽  
Predator Prey ◽  
Susceptibility To Infection ◽  
Density Reduction

Abstract Non-lethal predator-prey interactions during the immature stages can cause significant changes to mosquito life history traits and their ability to transmit pathogens as adults. Treatment manipulations using mosquitoes Aedes aegypti (L.) and Toxoryhnchites rutilus (Coquillett) were performed during the immature stages to explore the potential impacts of non-lethal interactions on adult susceptibility to infection, disseminated infection and saliva infection of Ae. aegypti following ingestion of Zika virus-infected blood. Treatments inducing density reduction resulted in reduced development time and survivorship to adulthood. However, effects of treatment did not alter infection, dissemination, or saliva infection. These observations indicate that, while non-lethal predation may impact some traits that influence population dynamics and transmission of pathogens, there were no direct effects on mosquito-arbovirus interactions.

The Calculation of the Thickness for Uniform Corrosion and Localized Corrosion in Steel Corrosion

2011 ◽  
Vol 255-260 ◽  
pp. 514-518
Author(s):  
Zheng Yi Kong ◽  
Shan Hua Xu ◽  
Yu Sheng Chen
Keyword(s):  
Corrosion Rate ◽  
Constant Temperature ◽  
Safety Assessment ◽  
Steel Corrosion ◽  
Localized Corrosion ◽  
Power Relationship ◽  
Uniform Corrosion ◽  
Experiment Data ◽  
Temperature And Humidity ◽  
Corrosion Pits

Because of the complexity of corrosion, the law of uniform corrosion and localized corrosion is still not clear,so it is difficult to assess their impact on the structure safety. In order to differ them and find their own law, we obtain a lot of corrosion specimens by ways of constant temperature and humidity, and then detect the size of corrosion pits by roughness tester. After that, the method for calculating the thickness of uniform corrosion and localized corrosion is proposed. Then the method is used to analyze the experiment data. The result indicates the thickness of uniform corrosion and localized corrosion all increase with the rate of corrosion, and they all show a power relationship with corrosion rate, so it will provide a basis for distinguishing them in safety assessment.

Observations on the free-living stages of the stomach worm Haemonchus contortus

Parasitology ◽  
1963 ◽  
Vol 53 (3-4) ◽  
pp. 469-481 ◽  
Author(s):  
J. H. Rose
Keyword(s):  
Haemonchus Contortus ◽  
Free Living ◽  
Rate Of Development ◽  
Temperature And Humidity ◽  
Survival And Development ◽  
Effects Of Temperature ◽  
Eggs And Larvae ◽  
Heavy Mortality

Outdoor observations were made on the rate of development of the free-living stages of H. contortus at different times of the year, and on the migratory activities and longevity of the larvae in faeces, on herbage and in soil.The effects of temperature and humidity on the survival and development of eggs and larvae, both in faeces and when separated from the faeces, were studied in the laboratory.The results of these observations are discussed in relation to the heavy mortality of the free-living stages of H. contortus and to the transmission of infection in the field.

Effect of phosphorus applied as superphosphate on rate of development and spikelet number per ear of different cultivars of wheat

1977 ◽  
Vol 28 (2) ◽  
pp. 183 ◽  
Author(s):  
MS Rahman ◽  
JH Wilson
Keyword(s):  
Constant Temperature ◽  
Leaf Number ◽  
Floral Initiation ◽  
Wheat Cultivars ◽  
Main Shoot ◽  
Spikelet Number ◽  
Vegetative Phase ◽  
Rate Of Development ◽  
Elongation Phase

The effects of adding phosphorus (40 kg of phosphorus ha-1) at sowing on rate of development, spikelet number per ear, rate of spikelet initiation, apex length at floral initiation, and leaf number at ear emergence of the main shoot of seven wheat cultivars were studied under a 16 hr photoperiod at a constant temperature of 20°C. Phosphorus additions increased the spikelet number per ear, rate of spikelet initiation, and apex length significantly in all wheats, but had no effect on the duration of the vegetative phase, spikelet phase or elongation phase, or on leaf number. The increase in spikelet number was due to an increase of spikelet initiation. All wheats responded similarly to addition of phosphorus.

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.

Sign in / Sign up

Export Citation Format

Share Document