scholarly journals Deviation of Dyar’s rule in the post-embryonic development in millipedes – a comprehensive analysis

2020 ◽  
Author(s):  
Somnath Bhakat
Keyword(s):  
Embryonic Development ◽  
Development Time ◽  
Habitat Utilization ◽  
Comprehensive Analysis ◽  
The Mean ◽  
Progression Factor

AbstractDyar’s value on the basis of length and width of nine polydesmid and 15 non-polydesmid millipede species were calculated. The value of polydesmid millipede ranged from 1.50 to 1.78 and that of non-polydesmid millipede ranged from 1.08 to 1.45. Weight progression factor was determined for nine species of millipede (two polydesmid and seven non-polydesmids). The result showed that the mean weight progression factor in polydesmid is 2.54 while that of non-polydesmid is 1.95. Both the results showed that Dyar’s value in polydesmida is significantly higher compared to that of non-polydesmida. In polydesmida, the number of stadium is only eight with higher Dyar’s value (mean 1.61) while in non-polydesmida, where number of stadium is more than eight have lower Dyar’s value (mean 1.23). As in other arthropods, Dyar’s value is inversely proportional to the number of stadium in millipede.The present study also affirmed Enders’ hypothesis in favour of adaptive importance of Dyar’s rule. Deviations from Dyar’s constant in these two group also support Crossby’s growth rule. The variation of Dyar’s value in these two groups of millipede is related to the development time and habitat utilization. The variation of weight progression factor in these two groups is also linked to the development time as observed in other arthropods.

scholarly journals Life Tables of Two-Spotted Spider Mite Tetranychus urticae Koch (Acari: Tetranychidae) and its Predator Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae)

1970 ◽  
Vol 16 ◽  
pp. 1-10 ◽  
Author(s):  
M Fazlul Hoque ◽  
W Islam ◽  
M Khalequzzaman
Keyword(s):  
Tetranychus Urticae ◽  
Generation Time ◽  
Development Time ◽  
Phytoseiulus Persimilis ◽  
Reproductive Rate ◽  
Finite Capacity ◽  
Net Reproductive Rate ◽  
Wide Range ◽  
The Mean ◽  
Capacity For Increase

Life table of Tetranychus urticae and Phytoseiulus persimilis on bean leaflets were studied under laboratory conditions in three seasons. For T. urticae the development time from egg to adult varied from 7 to 24 days and the highest immature mortality was 78.70 % in winter. Eggs laid by females were 88.1 eggs in autumn and 70.6 eggs in summer season. The gross reproductive rate (GRR) was the highest (65.51) in autumn and 52.50 in summer. The net reproductive rate (Ro) was the highest (15.862) in autumn and 8.916 in summer. The intrinsic rates of increase (rm) and finite capacity for increase (λ) reached maximal values (0.1873 and 1.206) in autumn, whereas minimal values (0.056 and 1.058) were in winter season. The mean generation time (T) was the shortest in summer and double (3.701) days in autumn. The development time of P. persimilis from egg to adult varied from 5 to 14 days. The highest immature mortality was 60% in summer. Eggs laid by females were 39.4 eggs in autumn and 30.2 eggs in summer. The gross reproductive rate (GRR) was the highest (31.4) in autumn and 24.0 in summer. The net reproductive rate (Ro) was the highest (10.573) in autumn and 8.460 in winter. The intrinsic rates of increase (rm) and finite capacity for increase (λ) reached maximal values (0.1823 and 1.200) in summer, whereas minimal values (0.1025 and 1.108) were in winter. The mean generation time (T) was the shortest in summer. The results suggested that P. persimilis could develop and reproduce within a wide range of temperatures. Key words: Tetranychus urticae, Phytoseiulus persimilis, immature mortality, intrinsic rates of increase, reproductive rate, Survival  DOI:10.3329/jbs.v16i0.3733 J. bio-sci. 16: 1-10, 2008

Development, Growth, and Survival of Lepeophtheirus Salmonis (Copepoda: Caligidae) Under Laboratory Conditions

1991 ◽  
Vol 71 (2) ◽  
pp. 425-436 ◽  
Author(s):  
S. C. Johnson ◽  
L. J. Albright
Keyword(s):  
Adult Female ◽  
Survival Data ◽  
Laboratory Experiments ◽  
Development Time ◽  
Lepeophtheirus Salmonis ◽  
Survival Times ◽  
Growth And Survival ◽  
Average Survival ◽  
Copepodid Stage ◽  
The Mean

Development, growth, and survival data derived from laboratory experiments are provided for Lepeophtheirus salmonis, a common ectoparasite of wild and sea-farmed salmonids. The mean development time of eggs was 419·1 hours (17·5 days) at 5°C, 207·1 hours (8·6 days) at 10°C, and 130·8 hours (5·5 days) at 15°C. Development from the first nauplius to the infectious copepodid stage took 222·3 hours (9·3 days) at 5°C, 87·4 hours (3·6 days) at 10°C, and 44·8 (1·9 days) hours at 15°C. Development from the egg to the adult male took 40 days, and from the egg to the adult female 52 days at 10°C. No egg development occurred at 10‰ salinity. At 15‰ eggs developed but failed to produce active nauplii. At higher salinities (20–3‰) active nauplii were produced, but copepodids were only obtained at 30‰. Copepodids survived for less than 1 day in waters with a salinity of 10‰ or less. At higher salinities (15–30‰) and temperatures of 5,10, and 15°C average survival times ranged between 2 and 8 days.

scholarly journals Accelerating retreat and high-elevation thinning of glaciers in central Spitsbergen

2016 ◽  
Vol 10 (3) ◽  
pp. 1317-1329 ◽  
Author(s):  
Jakub Małecki
Keyword(s):  
Little Ice Age ◽  
High Elevation ◽  
Comprehensive Analysis ◽  
Ice Age ◽  
The Arctic ◽  
Digital Elevation ◽  
Glacier Changes ◽  
The Mean ◽  
Geodetic Mass Balance ◽  
The 1960S

Abstract. Svalbard is a heavily glacier-covered archipelago in the Arctic. Dickson Land (DL), in the central part of the largest island, Spitsbergen, is relatively arid and, as a result, glaciers there are relatively small and restricted mostly to valleys and cirques. This study presents a comprehensive analysis of glacier changes in DL based on inventories compiled from topographic maps and digital elevation models for the Little Ice Age (LIA) maximum, the 1960s, 1990, and 2009/2011. Total glacier area has decreased by  ∼ 38 % since the LIA maximum, and front retreat increased over the study period. Recently, most of the local glaciers have been consistently thinning in all elevation bands, in contrast to larger Svalbard ice masses which remain closer to balance. The mean 1990–2009/2011 geodetic mass balance of glaciers in DL is among the most negative from the Svalbard regional means known from the literature.

Population Biology of Orangestriped Oakworm (Lepidoptera: Saturniidae) in Southeastern Virginia

1993 ◽  
Vol 28 (2) ◽  
pp. 218-229
Author(s):  
Mark A. Coffelt ◽  
Peter B. Schultz
Keyword(s):  
Population Biology ◽  
Development Time ◽  
First Generation ◽  
Second Generation ◽  
Egg Mass ◽  
Mass Size ◽  
Quercus Palustris ◽  
The Mean ◽  
Pupal Mortality ◽  
Egg Mass Size

Population biology of orangestriped oakworm, Anisota senatoria (J. E. Smith), was studied in southeastern Virginia. Egg mass size was larger on Quercus palustris Muench., pin oak, compared with Q. phellos L., willow oak. Females produced a sex pheromone that attracted male moths. Blacklight traps were not effective for monitoring A. senatoria adults. Peak male emergence occurred on 2 July, 4 days earlier than female. The mean life span was 33.5 days in the laboratory. Pupal mortality was high and only 1.2% of the pupae produced moths in 1989 and 1990. Pupae were capable of overwintering for two years in the field. The first report of a second generation from September - November was documented. Second generation A. senatoria oviposited more egg masses, infested more trees and had a longer development time compared with first generation. Large egg mass size, pupae that were capable of overwintering for two years and the presence of a second generation may partially explain the consistent A. senatoria populations that have occurred in southeastern Virginia.

scholarly journals Estimated hospitalizations attributed to norovirus and rotavirus infection in Canada, 2006–2010

2015 ◽  
Vol 143 (16) ◽  
pp. 3528-3537 ◽  
Author(s):  
V. K. MORTON ◽  
M. K. THOMAS ◽  
S. A. McEWEN
Keyword(s):  
Negative Binomial ◽  
Comprehensive Analysis ◽  
Administrative Databases ◽  
Total Annual Cost ◽  
Economic Costs ◽  
The Mean ◽  
Negative Binomial Models ◽  
Binomial Models ◽  
Canadian Healthcare System ◽  
Canadian Healthcare

SUMMARYEnteric viruses including norovirus and rotavirus are leading causes of gastroenteritis in Canada. However, only a small number of clinical cases are actually tested for these pathogens leading to systematic underestimation of attributed hospitalizations in administrative databases. The objective of this analysis was to estimate the number of hospitalizations due to norovirus and rotavirus in Canada. Hospitalization records for acute gastroenteritis-associated discharges at all acute-care hospitals in Canada between 2006 and 2011 were analysed. Cause-unspecified gastroenteritis hospitalizations were modelled using age-specific negative binomial models with cause-specified gastroenteritis admissions as predictors. The coefficients from the models were used to estimate the number of norovirus and rotavirus admissions. The total annual hospitalizations for rotavirus were estimated to be between 4500 and 10 000. Total annual hospitalizations for norovirus were estimated to be between 4000 and 11 000. The mean total annual cost associated with these hospitalizations was estimated to be at least $16 million for rotavirus and $21 million for norovirus (all figures in Canadian dollars). This study is the first comprehensive analysis of norovirus and rotavirus hospitalizations in Canada. These estimates provide a more complete assessment of the burden and economic costs of these pathogens to the Canadian healthcare system.

Topographic Quantitative EEG Response to Acute Caffeine Withdrawal: A Comprehensive Analysis of Multiple Quantitative Variables

2002 ◽  
Vol 33 (4) ◽  
pp. 178-188 ◽  
Author(s):  
Roy R. Reeves ◽  
Frederick A. Struve ◽  
Gloria Patrick
Keyword(s):  
Quantitative Eeg ◽  
Comprehensive Analysis ◽  
Relative Power ◽  
Caffeine Consumption ◽  
Double Blind ◽  
Caffeine Ingestion ◽  
Absolute Power ◽  
Caffeine Withdrawal ◽  
The Mean ◽  
Abstinence Period

Most previous studies of the neurophysiological effects of caffeine have focused on the effects of caffeine ingestion, and few studies have examined the effects of caffeine withdrawal. This open study evaluated the quantitative EEG (QEEG) changes occurring during a 4-day period of abstinence in subjects who habitually consume 300 mg or more of caffeine daily. Thirteen subjects underwent QEEG studies during their usual caffeine consumption (baseline) and on days 1,2, and 4 of a 4-day period of caffeine abstinence. Ten of the subjects underwent a second QEEG on day 4 that consisted of a period of recording after reinstitution of caffeine. A comprehensive analysis of multiple quantitative variables was performed for each study during the abstinence period and compared to the variables obtained at baseline for each subject. Changes occurring during caffeine abstinence included: 1) increases in theta absolute power over all cortical areas, 2) increases in delta absolute power over the frontal cortex, 3) decreases in the mean frequency of both the alpha and beta rhythm, 4) increase in theta relative power and decrease in beta relative power, and 5) significant changes in interhemispheric coherence. Most of these changes tended to return to pre-abstinence baseline levels rapidly after resumption of caffeine consumption. The caffeine withdrawal state affects a number of neurophysiological variables. Further investigation of the neurophysiological aspects of caffeine withdrawal using placebo controlled double blind assessment methods is warranted.

Embryonic development of the newt Triturus italicus in relation to temperature

1998 ◽  
Vol 19 (4) ◽  
pp. 345-355 ◽  
Author(s):  
S. Tripepi ◽  
F. Rossi ◽  
G. Peluso
Keyword(s):  
Embryonic Development ◽  
Development Time ◽  
Normal Development ◽  
Different Temperatures

AbstractThe embryonic development of Triturus italicus was observed at different temperatures. Normal development occurred between 10°C and 22.5°C. In this range of temperatures an hyperbolic relationship between development time and temperature was confirmed.

Clutch size influences embryonic stages at oviposition in a lizard with prolonged egg retention

2017 ◽  
Vol 38 (4) ◽  
pp. 557-561 ◽  
Author(s):  
Thomas Foucart ◽  
Benoit Heulin ◽  
Olivier Lourdais
Keyword(s):  
Body Size ◽  
Embryonic Development ◽  
Clutch Size ◽  
Development Time ◽  
Reproductive Effort ◽  
Resource Limitation ◽  
Egg Retention ◽  
Zootoca Vivipara ◽  
Female Relative ◽  
Clutch Mass

We examined the possible interaction between reproductive effort and embryonic stages at oviposition in oviparous form of the lizard Zootoca vivipara. Our results reveal that the percentage of total embryonic development time (%TEDT) reached at oviposition is negatively correlated to clutch size (adjusted to maternal body size). We found no influence of reproductive burden of female (relative clutch mass, RCM) on %TEDT. The significant effect of fecundity supports the hypothesis that a resource limitation such as oxygen may exist for developing embryos in oviducts. The absence of RCM effect suggests that the available space (abdominal burdening of the mother) does not limit the embryonic stages at oviposition.

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