Design of a Sampling Plan for Studies on the Population Dynamics of the Imported Cabbageworm, Pieris rapae (L.) (Lepidoptera: Pieridae)

1962 ◽  
Vol 94 (8) ◽  
pp. 849-859 ◽  
Author(s):  
D. G. Harcourt
Keyword(s):  
Population Dynamics ◽  
Pieris Rapae ◽  
Sampling Plan ◽  
Immature Stages ◽  
Mortality Factors ◽  
Term Study ◽  
Factors Affecting ◽  
Long Term Study ◽  
Successive Generations

In 1958, intensive studies on the population dynamics of the imported cabbageworm, Pieris rapae (L.), on cabbage were initiated in long-term study plots at Merivale, Ontario. The object was to construct ecological life tables for successive generations of the species, and ultimately, to develop mathematical models describing survival of field populations. This paper reports on the variation between samples of immature stages of the insect, and between some of the mortality factors affecting its abundance; it further illustrates the use of these data in designing a sampling plan with acceptable limits of precision.

Design of a Sampling Plan for Studies on the Population Dynamics of the Diamondback Moth, Plutella maculipennis (Curt.) (Lepidoptera: Plutellidae)

1961 ◽  
Vol 93 (9) ◽  
pp. 820-831 ◽  
Author(s):  
D. G. Harcourt
Keyword(s):  
Population Dynamics ◽  
Diamondback Moth ◽  
Sampling Plan ◽  
Immature Stages ◽  
Mortality Factors ◽  
Term Study ◽  
Factors Affecting ◽  
Long Term Study ◽  
Successive Generations

In 1958, intensive studies on the population dynamics of the diamondback moth, Plutella maculipennis (Curt.), on cabbage were initiated in long-term study plots at Merivale, Ontario. The object was to construct ecological life tables (Morris and Miller, 1954) for successive generations of the insect, and, ultimately, to develop a mathematical model describing survival of field populations. This paper reports on the variation between samples of immature stages of the moth, and between some of the mortality factors affecting its abundance, and on the use of these data in designing a sampling plan with acceptable limits of precision.

Spatial structure of harbour seal populations and the implications thereof

2001 ◽  
Vol 79 (12) ◽  
pp. 2115-2127 ◽  
Author(s):  
T Härkönen ◽  
K C Harding
Keyword(s):  
Population Dynamics ◽  
Site Fidelity ◽  
Phoca Vitulina ◽  
Population Increase ◽  
Dynamic Processes ◽  
Term Study ◽  
Long Term Study ◽  
Harbour Seals ◽  
Age And Sex

A long-term study of freeze-branded harbour seals (Phoca vitulina) revealed explicit site fidelity. Individuals were followed up to 14 years of age and none of the 163 branded animals were observed to haul out beyond a 32-km distance from the site where they were branded as pups. Within this range, striking spatial segregation by age and sex prevailed. While females' site fidelity increased with age, males spent less time at their natal site with increasing age. These findings have consequences for understanding the population dynamics of harbour seals, since single "colonies" will act as partly isolated "subpopulations" in some contexts but not in others. The differing migration tendencies of the population segments lead to spatially segregated sex and age ratios of subpopulations and create a complex pattern of connectivity among these subpopulations. Ignoring the spatial scale will lead to severe misinterpretations of analyses of basic population-dynamic processes, especially rates of population increase, rates of gene flow, and the dynamics of the spread of diseases. We suggest that when studies have different aims, these should be addressed by encompassing different numbers of subpopulations.

scholarly journals Climatic Factors, Reproductive Success and Population Dynamics in the Montane Vole, Microtus montanus

1991 ◽  
Vol 15 ◽  
pp. 162-164
Author(s):  
Aelita Pinter
Keyword(s):  
Population Dynamics ◽  
Reproductive Success ◽  
Population Density ◽  
Environmental Variables ◽  
Climatic Factors ◽  
Small Rodents ◽  
Term Study ◽  
Microtus Montanus ◽  
Long Term Study

Multiannual fluctuations in population density ("cycles") of small rodents have been known since antiquity (Elton 1942). Numerous hypotheses have been proposed to explain this phenomenon (for reviews see Finerty 1980, Taitt and Krebs 1985). However, none of these hypotheses, alone or in combination, have been able to explain the causality of cycles. The objectives of this long-term study are to determine whether environmental variables, possibly acting through reproductive responses, contribute to the multiannual fluctuations of the montane vole, Microtus montanus.

scholarly journals Climatic Factors, Reproductive Success and Population Dynamics in the Montane Vole, Microtus montanus

1987 ◽  
Vol 11 ◽  
pp. 103-105
Author(s):  
Aelita Pinter
Keyword(s):  
Population Dynamics ◽  
Reproductive Success ◽  
Population Density ◽  
Environmental Variables ◽  
Climatic Factors ◽  
Small Rodents ◽  
Term Study ◽  
Microtus Montanus ◽  
Long Term Study

Multiannual fluctuations in population density of small rodents have been known since antiquity. However, factors responsible for this phenomenon remain unknown (Krebs and Myers 1974, Finerty 1980, Taitt and Krebs 1985). The objectives of this long-term study are to determine whether environmental variables, possibly acting through reproductive responses, contribute to the multiannual fluctuations of the montane vole, Microtus montanus.

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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