scholarly journals Population dynamics of Saissetia oleae. II. Life-tables and key-factor analysis

2017 ◽  
Vol 8 ◽  
pp. 59 ◽  
Author(s):  
E. T. Kapatos ◽  
E.T. Stratopoulou
Keyword(s):  
Factor Analysis ◽  
Population Dynamics ◽  
Population Change ◽  
Life Tables ◽  
Population Fluctuations ◽  
Mortality Factors ◽  
Population System ◽  
Key Factor ◽  
Key Factor Analysis ◽  
Table Data

A series of life-tables for the population of Saisselia oleae (Oliv.) (Homoptera: Coccidae) during five yearly generations (1981-86) were constructed in Corfu. Key-factor analysis carried out on the life-table data indicated that mortality of young stages during summer, caused mainly by the high temperatures, and mortality during spring, caused mainly by predation, determine total population change within each generation. These two mortality factors are the predominant factors of the population dynamics of S. oleae determining population fluctuations. The other mortality factors of the population system of S. oleae were less important. Summer parasites and egg predators, in particular, do not play any significant role on the population dynamics of S. oleae.

A key-factor analysis of population fluctuations in Andraca bipunctata Walker (Lepidoptera: Bombycidae)

1979 ◽  
Vol 69 (1) ◽  
pp. 195-201 ◽  
Author(s):  
B. Banerjee
Keyword(s):  
Factor Analysis ◽  
Statistical Tests ◽  
Population Fluctuations ◽  
Female Mortality ◽  
Mortality Factors ◽  
Density Dependent ◽  
Key Factor ◽  
Key Factor Analysis ◽  
Insect Populations ◽  
Sampling Procedures

AbstractThe causes of fluctuation and stabilisation in a population of Andraca bipunctata Wlk. on tea in India were assessed over three years using the technique of key-factor analysis. Failure to produce the maximum complement of eggs, together with female mortality and adult migration, is shown to be the key-factor. Other mortality factors include non-viability of eggs and parasitism of the caterpillars by the tachinid Cylindromyia sp. Mortality of the female pupae tends to stabilise the population by compensating for losses due to the key-factor, but neither this nor any other mortality factors appear to be significantly density-dependent. The need for devising specialised sampling procedures and statistical tests for tropical insect populations is discussed.

Key-factor analysis of immature stages of Aedes scapularis (Diptera: Culicidae) populations in southeastern Brazil

2002 ◽  
Vol 92 (4) ◽  
pp. 271-277 ◽  
Author(s):  
C. Casanova ◽  
A.P. do Prado
Keyword(s):  
Larval Instar ◽  
Southeastern Brazil ◽  
Population Fluctuations ◽  
Mortality Factors ◽  
Breeding Sites ◽  
Final Population ◽  
Key Factor ◽  
Synchronous Development ◽  
Population Sizes ◽  
Key Factor Analysis

AbstractDevelopment times and mortality factors were investigated for populations of Aedes scapularis (Rondani) occurring in natural temporary ground pools in southeastern Brazil. Analysis of life tables by the key-factor method showed that mortality caused by desiccation of breeding sites was the principal factor accounting for fluctuations in population sizes throughout the study period. For cohorts that completed development, mortality attributed to predation by aquatic insects ranged from 68 to 96% and was the most important cause of death. In these cohorts, final population size was determined by the high mortality rates that occurred during the fourth larval instar and pupal stages; however, the key-factor best accounting for the population fluctuations was predation of fourth instar larvae. The short mean time of 7.1 days for synchronous development of the larvae and the lack of evidence of density-dependent mortality suggested that the A. scapularis populations were not strongly regulated and can attain relatively high densities.

Major Factors in Survival of the Immature Stages of Pieris rapae (L.)

1966 ◽  
Vol 98 (6) ◽  
pp. 653-662 ◽  
Author(s):  
D. G. Harcourt
Keyword(s):  
Population Dynamics ◽  
Survival Rate ◽  
Pieris Rapae ◽  
Pupal Stage ◽  
Population Data ◽  
Life Tables ◽  
Immature Stages ◽  
Mortality Factors ◽  
Key Factor ◽  
Major Factors

AbstractDetailed studies on the population dynamics of the imported cabbageworm, Pieris rapae (L.), have been carried out at Merivale, Ontario, since 1959. A method for preparing life tables is described and a mean life table is presented for 18 generations of the species on cabbage. Population data for the preadult period show that there are three age intervals during which extensive mortality may occur: (1) between hatching and the second moult, (2) instars three to five, and (3) during the pupal stage. The analysis of successive age-interval survivals in relation to generation survival showed that the latter is largely determined by the survival rate for (2). Examination of the life tables revealed that a granulosis of the larvae caused by a capsule virus is the key factor in generation survival. Major mortality factors include rainfall and parasites.

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