scholarly journals Potential-Growth Indicators Revisited: Higher Generality and Wider Merit of Indication

Mathematics ◽  
2021 ◽  
Vol 9 (14) ◽  
pp. 1649
Author(s):  
Dmitrii O. Logofet ◽  
Valerii N. Razzhevaikin
Keyword(s):  
Spectral Radius ◽  
Reproductive Rate ◽  
Matrix Population Models ◽  
Potential Growth ◽  
Net Reproductive Rate ◽  
Perennial Weed ◽  
Practical Applications ◽  
Structured Population ◽  
Calamagrostis Epigeios ◽  
Age Structured

The notion of a potential-growth indicator came to being in the field of matrix population models long ago, almost simultaneously with the pioneering Leslie model for age-structured population dynamics, although the term has been given and the theory developed only in recent years. The indicator represents an explicit function, R(L), of matrix L elements and indicates the position of the spectral radius of L relative to 1 on the real axis, thus signifying the population growth, or decline, or stabilization. Some indicators turned out to be useful in theoretical layouts and practical applications prior to calculating the spectral radius itself. The most senior (1994) and popular indicator, R0(L), is known as the net reproductive rate, and we consider two others, R1(L) and RRT(A), developed later on. All the three are different in terms of their simplicity and the level of generality, and we illustrate them with a case study of Calamagrostis epigeios, a long-rhizome perennial weed actively colonizing open spaces in the temperate zone. While the R0(L) and R1(L) fail, respectively, because of complexity and insufficient generality, the RRT(L) does succeed, justifying the merit of indication.

scholarly journals Potential-Growth Indicators Revisited: More Merits of Indication

2021 ◽  
Author(s):  
Dmitrii O. Logofet ◽  
Valerii N. Razzhevaikin
Keyword(s):  
Spectral Radius ◽  
Reproductive Rate ◽  
Matrix Population Models ◽  
Potential Growth ◽  
Net Reproductive Rate ◽  
Perennial Weed ◽  
Practical Applications ◽  
Structured Population ◽  
Calamagrostis Epigeios ◽  
Age Structured

The notion of potential-growth indicator came to being in the field of matrix population models long ago, almost simultaneously with the pioneering Leslie model for age-structured population dynamics, albeit the term has been given and the theory developed only recent years. The indicator represents an explicit function, R(L), of matrix L elements and indicates the position of the spectral radius of L relative to 1 on the real axis, thus signifying the population growth, or decline, or stabilization. Some indicators turned out useful in theoretical layouts and practical applications prior to calculating the spectral radius itself. The most senior (1994) and popular indicator, R0(L), is known as the net reproductive rate, and we consider two more ones, R1(L) and RRT(A), developed later on. All the three are different in what concerns their simplicity and the level of generality, and we illustrate them with a case study of Calamagrostis epigeios, a long-rhizome perennial weed actively colonizing open spaces in the temperate zone. While the R0(L) and R1(L) fail respectively because of complexity and insufficient generality, the RRT(L) does succeed, justifying the merit of indication.

Population dynamics of the plant pathogenic fungus Uncinula necator

1992 ◽  
Vol 70 (5) ◽  
pp. 942-946 ◽  
Author(s):  
Dan O. Chellemi ◽  
James J. Marois
Keyword(s):  
Population Growth ◽  
Pathogenic Fungus ◽  
Age Distribution ◽  
Reproductive Rate ◽  
Vitis Vinifera L ◽  
Uncinula Necator ◽  
Matrix Population Models ◽  
Net Reproductive Rate ◽  
Generation Times ◽  
Doubling Times

Cohort life tables were constructed and population parameters determined for Uncinula necator (Schw.) Burr. parasitizing the foliage of Vitis vinifera L. cv. Carignane at various temperatures. The net reproductive rate per individual conidium at 19, 22, 26, and 30 °C was 577, 2272, 1300, and 157 conidia per generation, respectively. Mean generation times ranged from 22.84 days at 19 °C to 13.60 days at 30 °C. Intrinsic growth rates (r) varied from 0.43 per day at 19 °C to 1.24 per day at 26 °C. Doubling times ranged from 0.56 days at 26 °C to 1.63 days at 19 °C. Matrix population models were used to project population growth. Stable age distributions at 19, 22, 26, and 30 °C were reached after 70, 50, 45, and 45 days, respectively. At a stable age distribution, greater than 96% of the population was contained in the first age-class (days 1 – 5). Key words: demography, cohort life table, grape powdery mildew, net reproductive rate, population growth rate.

scholarly journals Generation Time, Net Reproductive Rate, and Growth in Stage-Age-Structured Populations

2014 ◽  
Vol 183 (6) ◽  
pp. 771-783 ◽  
Author(s):  
Ulrich K. Steiner ◽  
Shripad Tuljapurkar ◽  
Tim Coulson
Keyword(s):  
Generation Time ◽  
Reproductive Rate ◽  
Structured Populations ◽  
Net Reproductive Rate ◽  
Age Structured

scholarly journals Comparative demography of the exotic Harmonia axyridis with other aphidophagous coccinellids reared on artificial diet

2014 ◽  
Vol 49 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Julianne Milléo ◽  
Francisco Sales Fernandes ◽  
Wesley Augusto Conde Godoy
Keyword(s):  
Life Table ◽  
Harmonia Axyridis ◽  
Reproductive Rate ◽  
The Other ◽  
Adult Longevity ◽  
Net Reproductive Rate ◽  
Anagasta Kuehniella ◽  
Survival Percentage ◽  
Comparative Demography ◽  
Biological Aspects

The objective of this work was to compare biological aspects and life table parameters of the coccinellids Harmonia axyridis, Cycloneda sanguineaand Hippodamia convergens. Insects were fed eggs of Anagasta kuehniella, and reared at 24.5±1ºC, 70±10% relative humidity, with a 12 hour photophase. Hippodamia convergenstook about 1.6 day to complete development, longer than H. axyridis, and 2.4 day longer than C. sanguinea.At immature stages, H. axyridisexhibited the highest survival percentage (49.2%), in comparison to the other coccinellids. For mean adult longevity, H. convergenswas deficient, in comparison with the other species. Mean period of pre oviposition was the longest in C. sanguinea; the longest oviposition time occurred for H. axyridis; and the post oviposition period was similar between the coccinellids. Considering the reproductive parameters, H. axyridisshowed the best performance in all aspects. For life table, the values of H. convergenswere higher than, although close, to those of H. axyridis. Nevertheless, the high net reproductive rate of H. axyridis showed this species potential to increase population size. The biological characteristics of the exotic H. axyridis favors its invasion and establishment in Brazil, corroborating results noticed in other countries.

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.

Plant Resistance in Some Modern Soybean Varieties May Favor Population Growth and Modify the Stylet Penetration of Bemisia tabaci (Hemiptera: Aleyrodidae)

2021 ◽  
Author(s):  
Mauricélia F Almeida ◽  
Clébson S Tavares ◽  
Euires O Araújo ◽  
Marcelo C Picanço ◽  
Eugênio E Oliveira ◽  
...  
Keyword(s):  
Population Growth ◽  
Bemisia Tabaci ◽  
Intrinsic Rate ◽  
Reproductive Rate ◽  
Genetically Engineered ◽  
Population Increase ◽  
Net Reproductive Rate ◽  
Bt Toxin ◽  
Demographic Performance

Abstract Complaints of severe damage by whiteflies in soybean fields containing genetically engineered (GE) varieties led us to investigate the role of transgenic soybean varieties expressing resistance to some insects (Cry1Ac Bt toxin) and to herbicide (glyphosate) on the population growth and feeding behavior of Bemisia tabaci (Gennadius) MEAM1 (Hemiptera: Aleyrodidae). In the laboratory, the whiteflies reared on the GE Bt soybeans had a net reproductive rate (R0) 100% higher and intrinsic rate of population increase (rm) 15% higher than those reared on non-GE soybeans. The increased demographic performance was associated with a higher lifetime fecundity. In electrical penetration graphs, the whiteflies reared on the GE soybeans had fewer probes and spent 50% less time before reaching the phloem phase from the beginning of the first successful probe, indicating a higher risk of transmission of whitefly-borne viruses. Data from Neotropical fields showed a higher population density of B. tabaci on two soybean varieties expressing glyphosate resistance and Cry1Ac Bt toxin. These results indicate that some GE soybean varieties expressing insect and herbicide resistances can be more susceptible to whiteflies than non-GE ones or those only expressing herbicide resistance. Most likely, these differences are related to varietal features that increase host-plant susceptibility to whiteflies. Appropriate pest management may be needed to deal with whiteflies in soybean fields, especially in warm regions, and breeders may want to consider the issue when developing new soybean varieties.

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