Capacity for Increase: A Useful Population Statistic

10.2307/2370 ◽  
1965 ◽  
Vol 34 (1) ◽  
pp. 77 ◽  
Author(s):  
R. Laughlin
Keyword(s):  
Population Statistic ◽  
Capacity For Increase

Studies on rates of development and reproduction of California red scale, Aonidiella aurantii (Mask.) (Homoptera : Diaspididae) on citrus

1972 ◽  
Vol 20 (1) ◽  
pp. 37 ◽  
Author(s):  
JR Willard
Keyword(s):  
Leaf Disk ◽  
Distilled Water ◽  
Aonidiella Aurantii ◽  
Innate Capacity ◽  
Disk Method ◽  
Capacity For Increase

Red scale were reared in the laboratory on disks cut from lemon leaves floated on distilled water in plastic vials. Scales could be reared to maturity on the disks and females would produce crawlers. Rates of development measured at four temperatures using the leaf disk method were similar to data reported by earlier authors. Unfertilized females were found to remain alive and could be fertilized up to 16 weeks after the second moult. On the average, the longevity of unfertilized females was shown to be 3.5 weeks longer than that of fertilized females. The fecundity of females collected from the field was measured at a series of constant temperatures. Estimates of the capacity for increase (rc) and the innate capacity for increase (rm were obtained at four temperatures. Both these statistics were shown to be greatly influenced by temperature; rc was found to be an underestimate of rm at higher temperatures.

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

BIOLOGY, LIFE TABLES, AND INNATE CAPACITY FOR INCREASE OF THE TWOSPOTTED SPIDER MITE, TETRANYCHUS URTICAE (ACARINA: TETRANYCHIDAE)

1981 ◽  
Vol 113 (5) ◽  
pp. 371-378 ◽  
Author(s):  
H. J. Herbert
Keyword(s):  
Tetranychus Urticae ◽  
Spider Mite ◽  
Life Stage ◽  
Life Tables ◽  
Threshold Temperature ◽  
Reproduction Rate ◽  
Twospotted Spider Mite ◽  
Innate Capacity ◽  
Capacity For Increase ◽  
Twospotted Spider

AbstractThe threshold temperature of development, life table, and innate capacity for increase of the twospotted spider mite, Tetranychus urticae Koch, were established from life stage development studies at constant temperatures. The threshold for development was determined to be 10.0°C. The durations in degree-days above 10°C from the beginning of the egg stage to adult for females were 141.3, 152.3, and 139.8; for males 134.2, 144.7, and 135.2 at 15°, 18°, and 21°C, respectively. Life tables were constructed and innate capacity for increase was .069, .156, and .372; net reproduction rate 20.8, 38.4, and 58.1; and mean generation time 44.0, 23.4, and 10.9 at 15°, 18°, and 21°C, respectively.

scholarly journals The capacity for increase in chromosomally polymorphic and monomorphic populations of Drosophila pseudoobscura

Heredity ◽  
1964 ◽  
Vol 19 (4) ◽  
pp. 597-614 ◽  
Author(s):  
Th Dobzhansky ◽  
R C Lewontin ◽  
O Pavlovsky
Keyword(s):  
Drosophila Pseudoobscura ◽  
Capacity For Increase

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.

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.

scholarly journals Dissection of the impact of prioritized QTL-linked and -unlinked SNP markers on the accuracy of genomic selection1

2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Ashley S. Ling ◽  
El Hamidi Hay ◽  
Samuel E. Aggrey ◽  
Romdhane Rekaya
Keyword(s):  
Genomic Prediction ◽  
Complex Traits ◽  
Negative Impact ◽  
Pearson Correlation ◽  
Genetic Selection ◽  
Snp Markers ◽  
False Positives ◽  
Population Statistic ◽  
The Impact ◽  
Genomic Predictions

Abstract Background Use of genomic information has resulted in an undeniable improvement in prediction accuracies and an increase in genetic gain in animal and plant genetic selection programs in spite of oversimplified assumptions about the true biological processes. Even for complex traits, a large portion of markers do not segregate with or effectively track genomic regions contributing to trait variation; yet it is not clear how genomic prediction accuracies are impacted by such potentially nonrelevant markers. In this study, a simulation was carried out to evaluate genomic predictions in the presence of markers unlinked with trait-relevant QTL. Further, we compared the ability of the population statistic FST and absolute estimated marker effect as preselection statistics to discriminate between linked and unlinked markers and the corresponding impact on accuracy. Results We found that the accuracy of genomic predictions decreased as the proportion of unlinked markers used to calculate the genomic relationships increased. Using all, only linked, and only unlinked marker sets yielded prediction accuracies of 0.62, 0.89, and 0.22, respectively. Furthermore, it was found that prediction accuracies are severely impacted by unlinked markers with large spurious associations. FST-preselected marker sets of 10 k and larger yielded accuracies 8.97 to 17.91% higher than those achieved using preselection by absolute estimated marker effects, despite selecting 5.1 to 37.7% more unlinked markers and explaining 2.4 to 5.0% less of the genetic variance. This was attributed to false positives selected by absolute estimated marker effects having a larger spurious association with the trait of interest and more negative impact on predictions. The Pearson correlation between FST scores and absolute estimated marker effects was 0.77 and 0.27 among only linked and only unlinked markers, respectively. The sensitivity of FST scores to detect truly linked markers is comparable to absolute estimated marker effects but the consistency between the two statistics regarding false positives is weak. Conclusion Identification and exclusion of markers that have little to no relevance to the trait of interest may significantly increase genomic prediction accuracies. The population statistic FST presents an efficient and effective tool for preselection of trait-relevant markers.

Innate Capacity for Increase

2008 ◽  
pp. 1925-1925
Author(s):  
John B. Heppner ◽  
D. G. Boucias ◽  
J. C. Pendland ◽  
Andrei Sourakov ◽  
Timothy Ebert ◽  
...  
Keyword(s):  
Innate Capacity ◽  
Capacity For Increase

Experiments on the relative abundance of two sibling species of grain weevils.

1954 ◽  
Vol 2 (1) ◽  
pp. 66 ◽  
Author(s):  
LC Birch
Keyword(s):  
Relative Abundance ◽  
Sibling Species ◽  
Large Strain ◽  
Small Strain ◽  
The Other ◽  
Stored Grain ◽  
Stored Wheat ◽  
Innate Capacity ◽  
Series Of Experiments ◽  
Capacity For Increase

The small "strain" and the large "strain" of Calandra oryzae L. are sibling species. The small "strain" is common in stored wheat and rare in stored maize. The reverse is true for the large "strain." A series of four experiments showed how wheat favoured the small "strain" and how maize favoured the large "strain." Given a choice of wheat and maize the small "strain" and the large "strain" laid most of their eggs in wheat but the proportion was larger for the small "strain" as compared with the large "strain." When the insects were reared for several generations in wheat they laid more of their eggs in wheat. Likewise when reared in maize they laid more of their eggs in maize. But this "host conditioning" was not sufficient to prevent them from laying many eggs in the "wrong" grain. The innate capacity for increase of the small "strain" was greater than that of the large "strain" in wheat but in maize the large "strain" had a greater innate capacity for increase than the small "strain." In crowded cultures wheat again favoured the small "strain" by permitting greater maximum populations as compared with the large "strain." Maize favoured the large "strain" in this respect. When the two "strains" occurred together in crowded cultures one always drove the other out. The small "strain" was the successful one in wheat and the large "strain" was the successful one in maize. Although these four series of experiments illustrate ways in which wheat favours the small "strain" and maize favours the large "strain" they do not, in themselves alone, account for the segregation of the two "strains" in stored grain.

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