The effects of age, temperature, light quantity and wavelength on the swimming behaviour of the cercariae of Cryptocotyle lingua (Digenea: Heterophyidae)

Parasitology ◽  
1992 ◽  
Vol 105 (1) ◽  
pp. 131-137 ◽  
Author(s):  
J. G. Rea ◽  
S. W. B. Irwin
Keyword(s):  
Life Span ◽  
Water Temperature ◽  
Light Source ◽  
Laboratory Experiments ◽  
Temperature Dependent ◽  
Release Point ◽  
Successful Transmission ◽  
Active Life ◽  
Light Quantity ◽  
Precipitous Decline

Laboratory experiments indicated that the active life-span of the cercariae of Cryptocotyle lingua was temperature-dependent. An increase in water temperature and population age both correlated with a tendency for the organisms to become decaudate. The larvae were strongly photoresponsive to lateral light but with time, horizontal swimming rates (HSRs) from release point to light source progressively declined. When measured over a range of light quantities, HSRs peaked at 30 μM/m2/s. HSRs were also influenced by water temperature. A rapid increase occurred up to 15 °C after which there was a precipitous decline. HSRs to coloured light were negatively correlated with increasing wavelength. When offered a choice between colours, cercariae favoured the shorter wavelengths. The implications of these responses for successful transmission are discussed.

Daytime avoidance of chemosensory alarm cues by adult sea lamprey (Petromyzon marinus)

2014 ◽  
Vol 71 (6) ◽  
pp. 824-830 ◽  
Author(s):  
Richard T. Di Rocco ◽  
Cowan F. Belanger ◽  
István Imre ◽  
Grant E. Brown ◽  
Nicholas S. Johnson
Keyword(s):  
Water Temperature ◽  
Avoidance Response ◽  
Laboratory Experiments ◽  
Petromyzon Marinus ◽  
Sea Lamprey ◽  
Human Saliva ◽  
Effect Of Temperature ◽  
Alarm Cues ◽  
Temperature Dependent ◽  
Daytime Activity

Sea lamprey (Petromyzon marinus) avoid damage-released and predator chemosensory cues at night, but their response to these cues during the day is unknown. Here, we explored (i) whether sea lamprey avoid these cues during the day and (ii) the effect of water temperature on the avoidance of chemosensory alarm cues in two diurnal laboratory experiments. We hypothesized that daytime activity would be temperature-dependent and that only sea lamprey vulnerable to predation (i.e., not hiding) would behaviourally respond to chemosensory alarm cues. Ten groups of ten sea lamprey were exposed to one of a variety of potential chemosensory cues. The experiments were conducted over a range of temperatures to quantify the effect of temperature on avoidance behaviour. Consistent with our hypothesis, a higher proportion of animals were active during daytime as water temperature increased. Moving sea lamprey showed an avoidance response to 2-phenylethylamine (a compound found in mammalian urine) and human saliva once water temperatures had risen to mean (±SD) = 13.7 (±1.4) °C. Resting and hiding sea lamprey did not show an avoidance response to any of the experimental stimuli.

Temperature-dependent survival and reproduction within populations of the ectoparasitic digenean Transversotrema patialense on the fish host

Parasitology ◽  
1980 ◽  
Vol 81 (1) ◽  
pp. 91-102 ◽  
Author(s):  
C. A. Mills
Keyword(s):  
Life Span ◽  
Egg Production ◽  
Fish Host ◽  
Adult Parasite ◽  
Optimum Temperature ◽  
Brachydanio Rerio ◽  
Temperature Dependent ◽  
Parasite Survival ◽  
Survival And Reproduction ◽  
Increasing Temperature

SUMMARYThe reproduction and survival of the ectoparasitic digenean Transversotrema patialense on the fish host Brachydanio rerio are shown to be temperature-dependent. Survival is reduced by any deviation from an optimum temperature of approximately 23°C. With increasing temperature the rate of egg production per surviving fluke rises progressively faster to a higher peak up to 29°C but falls to zero by 35°C. The span of egg production varies closely with the life-span of the parasite at each temperature. The optimum temperature for the total number of eggs produced by each cohort of parasites is also 23°C. This number is a function of both adult parasite survival and the rate of egg output.

Environmental control of reproduction in Perinereis nuntia var. brevicirrus

1994 ◽  
Vol 74 (4) ◽  
pp. 903-918 ◽  
Author(s):  
J.D. Hardege ◽  
H.D. Bartels-Hardege ◽  
Y. Yang ◽  
B.L. Wu ◽  
M.Y. Zhu ◽  
...  
Keyword(s):  
Water Temperature ◽  
Rocky Shore ◽  
Sex Pheromones ◽  
Laboratory Experiments ◽  
Environmental Control ◽  
Early Morning ◽  
Early Summer ◽  
Coelomic Fluid ◽  
Spawning Behaviour ◽  
Perinereis Nuntia

Perinereis nuntia brevicirrus (Grube 1857), collected from a rocky shore at Qingdao (China) were cultured under different temperature, daylength and moonlight regimes. Ripe individuals were found in the field after an increase of water temperature in early summer, with a semilunar spawning peak from the beginning of June to the end of September. In laboratory experiments, daylength has no influence on maturation and reproduction. Temperature-controlled culture produces gravid, reproducing specimens at any time of the year after an increase in water temperature. For reproduction both sexual partners leave their burrows and swarm at the water surface in the early morning, performing a nuptial dance. The spawning behaviour, the nuptial dance and the release of gametes, are controlled by sex pheromones which are present in the coelomic fluid of mature worms. A sex pheromone from Platynereis dumerilü, 5-methyl-3-heptanone, is found in Perinereis nuntia brevicirrus and causes an increase in swimming activity during reproduction and the release of a small amount of sperm from males. This signal induces the release of eggs by the females followed by the release of masses of sperm by the male due to a second female pheromone.

Behavioural responses of the cercariae of Cryptocotyle lingua (Digenea: Heterophyidae) to computer-controlled shadow sequences

Parasitology ◽  
1991 ◽  
Vol 103 (3) ◽  
pp. 471-477 ◽  
Author(s):  
J. G. Rea ◽  
S. W. B. Irwin
Keyword(s):  
Laboratory Experiments ◽  
Muscular Activity ◽  
Finite Energy ◽  
Fish Host ◽  
Activity Levels ◽  
Energy Reserves ◽  
Population Activity ◽  
Behavioural Responses ◽  
Active Life ◽  
Computer Controlled

The cercariae of Cryptocotyle lingua have a brief but active life during which they do not feed. In order to maximize the probability of infection they must respond to a variety of host-related stimuli yet conserve their finite energy reserves by minimizing unnecessary muscular activity. In laboratory experiments, simulated shadows representing the passage of a fish host were found to increase population activity levels. Evidence was also found for a relationship between shadow duration and the duration of subsequent bursts of swimming activity. Adaptation to continuous shadowing was recorded, its onset and magnitude being dependent on both the frequency and duration of shadows delivered. As cercariae aged they became less responsive to shadow stimuli, especially those of short duration.

scholarly journals Laboratory experiments on shear failure of snow

1998 ◽  
Vol 26 ◽  
pp. 97-102 ◽  
Author(s):  
Jürg Schweizer
Keyword(s):  
Laboratory Experiments ◽  
Shear Failure ◽  
Failure Strain ◽  
Failure Stress ◽  
Homogeneous Layer ◽  
Strain Rates ◽  
Temperature Dependent ◽  
Direct Simple Shear ◽  
Dependent Property ◽  
Snow Samples

Using a direct simple-shear apparatus, snow samples (115 mm in diameter, 16–18 mm in height) taken from a so-called homogeneous layer (small rounded particles, density: 290 kg m−3) were tested in a cold laboratory. Experiments were performed for strain rates between 7 × 10−6 s−1 and 5 × 10−3 s−1 at test temperatures of −5°C, −10°C and −15°C. The effects of strain rate and temperature on failure stress, failure strain, stiffness (initial tangent modulus) and toughness were studied. The transition between the ductile and brittle (sudden fracture) state of failure was found to be at about 1 × 10−3 s−1 for the snow types tested, independent of temperature. Stiffness proved to be the most temperature-dependent property of alpine snow. It strongly increases with decreasing temperature. Failure strain and toughness decrease with decreasing temperature. Failure stress was found to increase slightly with decreasing temperature. The effect is not very distinct but close to statistically significant and might be partly hidden by the scatter in the stress data due to variations inherent in sampling and testing.

Protein-feeding by the males of the Australian bushfly Musca vetustissima Wlk. in relation to mating performance

1971 ◽  
Vol 60 (4) ◽  
pp. 607-614 ◽  
Author(s):  
Marina Tyndale-Biscoe
Keyword(s):  
Life Span ◽  
Sexual Activity ◽  
Mating Success ◽  
Laboratory Experiments ◽  
Lucilia Cuprina ◽  
Behaviour Pattern ◽  
Laboratory Conditions ◽  
Protein Feeding ◽  
Mating Performance

Male bushflies (Musca vetustissima Wlk.) are attracted to and feed on proteincontaining substances, although under laboratory conditions they ingested smaller quantities of blood and dung than did the females. Laboratory experiments showed that they are able to obtain water from fresh dung and blood, but no physiological requirement for the protein was found. Feeding on protein did not increase the life span or the total numbers of matings; it did not improve the mating success of males that had previously been multiple-mated; and it did not enhance sexual activity, contrary to the situation found in Lucilia cuprina (Wied.). It is concluded that protein feeding in male bushflies is casual, possibly a behaviour pattern that ensures their presence near females.

Temperature-dependent reproduction and survival of Gyrodactylus salaris Malmberg, 1957 (Platyhelminthes: Monogenea) on Atlantic salmon (Salmo salar L.)

Parasitology ◽  
1991 ◽  
Vol 102 (1) ◽  
pp. 105-112 ◽  
Author(s):  
P. A. Jansen ◽  
T. A. Bakke
Keyword(s):  
Atlantic Salmon ◽  
Water Temperature ◽  
Salmo Salar ◽  
Temperature Dependent ◽  
Survival And Reproduction ◽  
Two Temperatures ◽  
The Mean ◽  
Relationship Of ◽  
The Relationship ◽  
Capacity For Increase

SUMMARYThe relationship of survival and reproduction of Gyrodactylus salaris Malmberg on the Atlantic salmon (Salmo salar) to water temperature (2·5–19·0 °C), was studied on the basis of temporal sequence of births and age at death of individual parasites on isolated salmon, and of infrapopulation growth on isolated and grouped salmon. Mean life-span of the parasite was negatively correlated with water temperature: 33·7 days at 2·5 °C and 4·5 days at 19·0 °C. The average number of offspring per parasite peaked between 6·5 and 13·0 °C, and was approximately 2·4 at these two temperatures. Both the period between the successive births of the offspring (max 4) and the estimated generation time were negatively correlated with temperature. The innate capacity for increase (rm) was positively correlated with temperature: from 0·02 (/parasite/day) at 2·5 °C to 0·22 (/parasite/day) at 19·0 °C. Growth of the infrapopulations was positively correlated with water temperature and was higher on isolated fish than on grouped fish, though less than the potential parasite population growth estimated from rm. In the infrapopulations the mean intensity of parasites continued to increase throughout all the experiments on both isolated fish and on grouped fish.

Research of Dinosaurs Weathering Mechanism in Zhucheng Shandong

2015 ◽  
Vol 723 ◽  
pp. 757-762 ◽  
Author(s):  
Shang Kun Zhang ◽  
Sheng Xian Du ◽  
Xue Feng Yu ◽  
Guo Rong Zhang ◽  
Xiang Yu Luo ◽  
...  
Keyword(s):  
Water Temperature ◽  
Numerical Experiments ◽  
Laboratory Experiments ◽  
Reference Value ◽  
Scientific Basis ◽  
Geological Heritage ◽  
Physical Models ◽  
Process Water ◽  
Excavation Process ◽  
Weathering Process

In recent years, more and more domestic and international dinosaur fossils geological heritage were found, and many dinosaur fossils severe weathering within a few years after excavation.This study were based on Zhucheng dinosaur fossils ,the research of weathering mechanism of dinosaur fossils were from aspects of physical - mechanical characteristics.Means of laboratory experiments, physical models, theories and numerical experiments were used to explores the effect of weathering by the factors of excavation process, water, temperature , acidic substances and other factors on dinosaur fossils and relics.The results reveal the physical destruction of Shandong Zhucheng dinosaur fossils in the mechanism and characteristics of weathering process can provide theoretical and scientific basis for the protection of fossils, and other parts of the mechanism of weathering and protection of dinosaur fossils study provides reference value.

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