DETERMINISTIC AND STOCHASTIC MODELS SIMULATING THE GROWTH OF INSECT POPULATIONS OVER A RANGE OF TEMPERATURES UNDER MALTHUSIAN CONDITIONS

1976 ◽  
Vol 108 (9) ◽  
pp. 907-924 ◽  
Author(s):  
J. M. Hardman
Keyword(s):  
Stochastic Model ◽  
Population Growth ◽  
Life Table ◽  
Stochastic Models ◽  
Input Data ◽  
Computer Experiments ◽  
Tribolium Confusum ◽  
Life Table Parameters ◽  
Chance Events ◽  
Insect Populations

AbstractThe concept of degree-day summation was employed in three models of malthusian growth predictive over a range of temperatures. When supplied input data from life table studies conducted at five constant temperatures, the models were able to predict the magnitude and pattern of growth of populations of Tribolium confusum Duval reared under malthusian conditions. The stochastic model, moreover, revealed that the series of chance events found in the course of population growth could explain differences between one population and the next. When computer experiments on the importance of various life table parameters were run, the models revealed the overwhelming importance of time taken to mature on the rate of population growth. The level of fecundity was next in order of importance while population growth was least sensitive to changes in survivorship.

scholarly journals Effect of temperature on population growth and life table parameters of Nephus arcuatus (Coleoptera: Coccinellidae)

2014 ◽  
Vol 111 (2) ◽  
pp. 199-206 ◽  
Author(s):  
Sara ZARGHAMI ◽  
Farhan KOCHEILI ◽  
Mohammad S. MOSSADEGH ◽  
Hossein ALLAHYARI ◽  
Arash RASEKH
Keyword(s):  
Population Growth ◽  
Life Table ◽  
Effect Of Temperature ◽  
Life Table Parameters

Effects of delayed mating on the reproductive biology of the vine mealybug, Planococcus ficus (Hemiptera: Pseudococcidae)

2017 ◽  
Vol 108 (2) ◽  
pp. 263-270 ◽  
Author(s):  
A. Lentini ◽  
A. Mura ◽  
E. Muscas ◽  
M.T. Nuvoli ◽  
A. Cocco
Keyword(s):  
Population Growth ◽  
Life Table ◽  
Growth Rates ◽  
Oviposition Period ◽  
Population Doubling ◽  
Population Doubling Time ◽  
Life Table Parameters ◽  
Planococcus Ficus ◽  
Population Growth Rates ◽  
Vine Mealybug

AbstractThe effect of increasing mating delay on the reproductive performance and population growth rates of the vine mealybug, Planococcus ficus (Signoret) (Hemiptera: Pseudococcidae), was investigated under laboratory conditions. Virgin females were mated at 1, 3, 5, 7, 14, 21 and 28 days after emergence and reproductive and life table parameters were estimated. The pre-oviposition period (number of days between mating and the onset of oviposition) significantly decreased in females mated within 7 days, whereas females mated at older ages showed equivalent pre-oviposition periods (<4 days). The length of the oviposition period did not vary with increasing age at mating. Female longevity significantly increased in females mated at 21 and 28 days, as a consequence of a longer pre-reproductive period. Fecundity and sex ratio were not affected by the female age at mating, whereas fertility was higher in mealybugs mated at older ages. Additional field observations highlighted that young and old virgin females were equally able to attract males, as both mated on the same day as the field release. Mating delay also affected the life table parameters of P. ficus, as the intrinsic and finite rates of increase did not differ in mealybugs mated within 7 days and significantly decreased in females mated at older ages. The mean generation time and the population doubling time were overall similar in females mated at 1–7 days, and increased significantly in females that experienced longer mating delays. In terms of the mating disruption control of P. ficus, our findings indicate that this method would be effective if mating is delayed >7 days, as shorter delays in mating did not reduce the population growth rates.

GPS-BDS-Galileo double-differenced stochastic model refinement based on least-squares variance component estimation

2021 ◽  
pp. 1-16
Author(s):  
Hong Hu ◽  
Xuefeng Xie ◽  
Jingxiang Gao ◽  
Shuanggen Jin ◽  
Peng Jiang
Keyword(s):  
Stochastic Model ◽  
Least Squares ◽  
Stochastic Models ◽  
Variance Component ◽  
Satellite System ◽  
Variance Component Estimation ◽  
Short Baseline ◽  
Component Estimation ◽  
Zero Baseline ◽  
Global Navigation Satellite

Abstract Stochastic models are essential for precise navigation and positioning of the global navigation satellite system (GNSS). A stochastic model can influence the resolution of ambiguity, which is a key step in GNSS positioning. Most of the existing multi-GNSS stochastic models are based on the GPS empirical model, while differences in the precision of observations among different systems are not considered. In this paper, three refined stochastic models, namely the variance components between systems (RSM1), the variances of different types of observations (RSM2) and the variances of observations for each satellite (RSM3) are proposed based on the least-squares variance component estimation (LS-VCE). Zero-baseline and short-baseline GNSS experimental data were used to verify the proposed three refined stochastic models. The results show that, compared with the traditional elevation-dependent model (EDM), though the proposed models do not significantly improve the ambiguity resolution success rate, the positioning precision of the three proposed models has been improved. RSM3, which is more realistic for the data itself, performs the best, and the precision at elevation mask angles 20°, 30°, 40°, 50° can be improved by 4⋅6%, 7⋅6%, 13⋅2%, 73⋅0% for L1-B1-E1 and 1⋅1%, 4⋅8%, 16⋅3%, 64⋅5% for L2-B2-E5a, respectively.

scholarly journals Effects of Delayed Mating on the Reproductive Performance of Henosepilachna vigintioctopunctata (F.) (Coleoptera: Coccinellidae)

Insects ◽  
2021 ◽  
Vol 12 (7) ◽  
pp. 629
Author(s):  
Ya-Ling Wang ◽  
Qi-Nian Jin ◽  
Xiang-Ping Wang
Keyword(s):  
Life Table ◽  
Mating Success ◽  
Doubling Time ◽  
Reproductive Rate ◽  
Oviposition Period ◽  
Population Doubling ◽  
Life Table Parameters ◽  
Effective Measure ◽  
Net Reproductive Rate ◽  
Henosepilachna Vigintioctopunctata

Henosepilachna vigintioctopunctata (F.) is a serious pest of numerous solanaceous crops in many Asian countries. The purpose of this study was to clarify the effects of delayed mating on mating success, fecundity, fertility, pre-oviposition period, oviposition period, adult longevity, and population life table parameters (including net reproductive rate, intrinsic and finite rates of increase, doubling time, and mean generation time) of H. vigintioctopunctata. Beginning three days after emergence for both sexes, mating was delayed an additional 0, 2, 4, 6, or 8 days. We compared the data when mating was delayed for males only with the data when mating was similarly delayed for females only. Reproductive and life table parameters were calculated from the two data sets and compared. The results showed that the preoviposition and oviposition period of adults was significantly reduced by delayed mating, while the preoviposition period was not significantly different in adults mated at older ages. The mating success rate, fecundity, and proportion of hatching eggs decreased with increasing mating age. Longevity was not affected by the age at mating. Mating delay also affected the life table parameters of H. vigintioctopunctata, with a similar trend observed in the net reproductive rate and intrinsic and finite rates of increase, all of which decreased gradually as the number of delay days increased. The population doubling time increased with increases in mating age. The results also showed that delayed mating was an effective measure to consider in controlling H. vigintioctopunctata. It is hoped that our data will provide a scientific basis and contribute technical guidance for forecasting and integrated management of this pest.

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