Population growth and intrinsic rate of natural increase of the high arctic nematode Chiloplacus sp. at low and high temperatures

Oecologia ◽  
1984 ◽  
Vol 62 (1) ◽  
pp. 138-140 ◽  
Author(s):  
D. L. C. Procter
Keyword(s):  
Population Growth ◽  
High Temperatures ◽  
Intrinsic Rate ◽  
High Arctic ◽  
Natural Increase

scholarly journals Demography and perturbation analyses of the coffee berry borer Hypothenemus hampei (Coleoptera: Curculionidae): Implications for management

PLoS ONE ◽  
2021 ◽  
Vol 16 (12) ◽  
pp. e0260499
Author(s):  
Yobana A. Mariño ◽  
Paul Bayman ◽  
Alberto M. Sabat
Keyword(s):  
Population Growth ◽  
Developmental Stages ◽  
Intrinsic Rate ◽  
Natural Increase ◽  
Vital Rates ◽  
Hypothenemus Hampei ◽  
Coffee Berry ◽  
Coffee Berry Borer ◽  
Adult Females ◽  
Cultural Measures

The coffee berry borer (CBB) Hypothenemus hampei Ferrari is the most serious pest of coffee worldwide. Management of the CBB is extremely difficult because its entire life cycle occurs inside the fruit, where it is well protected. Knowing which life stages contribute most to population growth, would shed light on the population dynamics of this pest and help to improve CBB management programs. Two staged-classified matrices were constructed for CBB populations reared in the lab on artificial diets and CBB populations from artificial infestations in the field. Matrices were used to determine demographic parameters, to conduct elasticity analyses, and to perform prospective perturbation analysis. Higher values of the intrinsic rate of natural increase (rm) and population growth rate (λ): were observed for CBB populations growing in the lab than in the field (rm: 0.058, λ: 1.74 lab; rm: 0.053, λ: 1.32 field). Sensitivity values for both CBB populations were highest for the transitions from larva to pupa (G2: 0.316 lab, 0.352 field), transition from pupa to juvenile (G3: 0.345 lab, 0.515 field) and survival of adult females (P5: 0.324 lab, 0.389 field); these three vital rates can be important targets for CBB management. Prospective perturbation analyses indicated that an effective management for the CBB should consider multiple developmental stages; perturbations of >90% for each transition are necessary to reduce λ to <1. However, when the three vital rates with highest sensitivity are impacted at the same time, the percentage of perturbation is reduced to 25% for each transition; with these reductions in survival of larvae, pupae and adult females the value of λ was reduced from 1.32 to 0.96. Management programs for CBB should be focused on the use of biological and cultural measures that are known to affect these three important targets.

Comparative development, longevity and population growth of exotic and native parasitoids of lepidopteran cereal stemborers in Kenya

2001 ◽  
Vol 91 (5) ◽  
pp. 347-353 ◽  
Author(s):  
J.C. Mbapila ◽  
W.A. Overholt
Keyword(s):  
Population Growth ◽  
Adult Emergence ◽  
Intrinsic Rate ◽  
Natural Increase ◽  
Cotesia Flavipes ◽  
Effect Of Temperature ◽  
Cotesia Sesamiae ◽  
Comparative Development ◽  
Native Parasitoids ◽  
The Mean

AbstractStudies on the effect of temperature on the development, longevity and population growth of Cotesia flavipes Cameron and Cotesia sesamiae (Cameron) indicated that the development of both Cotesia spp. from oviposition to cocoon formation and adult emergence was inversely to temperature. The longevity of the parasitoids was also inversely related to temperature. Both parasitoids lived longer when moisture and food (agar + honey/water) were provided. The mean number of females and total adult progeny produced by C. flavipes on two host were, in most cases, higher than C. sesamiae. The intrinsic rate of natural increase of C. flavipes was higher than that of C. sesamiae.

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.

Influence of temperature on life history traits of the free-living, bacterial-feeding nematode Panagrolaimus sp. strain NFS-24

Nematology ◽  
2013 ◽  
Vol 15 (8) ◽  
pp. 939-946 ◽  
Author(s):  
Farhana Ayub ◽  
Olaf Strauch ◽  
Laurent Seychelles ◽  
Ralf-Udo Ehlers
Keyword(s):  
Intrinsic Rate ◽  
Analysis Data ◽  
Natural Increase ◽  
Population Doubling ◽  
Food Density ◽  
Hanging Drop ◽  
Free Living ◽  
Single Male ◽  
Different Temperatures ◽  
Hanging Drop Method

Life cycle analysis data of the free-living, bacterial-feeding Panagrolaimus sp. strain NFS 24-5 were assessed at different temperatures using a hanging drop method with single male and female individuals and a food density of 3 × 109 Escherichia coli cells ml−1. Lifespan at the moment when the first egg was laid was 5.7 days at 21°C and 4 days at 25, 27 and 29°C. The intrinsic rate of natural increase () was 0.53 at 21°C, 0.81 at 25°C, 0.93 at 27°C and 0.81 at 29°C, corresponding to population doubling times () of 1.3, 0.9, 0.7 and 0.9 days, respectively. Over 200 offspring per female were produced at 27°C. All other temperatures yielded fewer offspring. When females were kept without males, the life span was 49 days, whereas the last reproductive female (hanging drop with male individual) died after 16.5 days. These data will contribute to the interpretation of nematode population dynamics recorded in liquid culture.

scholarly journals Reproduction and survival of Muscina stabulans under laboratory conditions

2010 ◽  
Vol 40 (3) ◽  
pp. 674-677 ◽  
Author(s):  
Rodrigo Ferreira Krüger ◽  
Paulo Bretanha Ribeiro ◽  
Simone Giehl Erthal ◽  
Og DeSouza
Keyword(s):  
Population Growth ◽  
Quantitative Estimate ◽  
Intrinsic Rate ◽  
Reproduction Rate ◽  
Rapid Population Growth ◽  
Artificial Diets ◽  
Adaptation Capacity ◽  
Laboratory Conditions ◽  
Published Report ◽  
Rearing Conditions

This is the first published report concerning reproduction and survival using life table analyses of fertility and survival for Muscina stabulans maintained under laboratory conditions with artificial diets. The intrinsic rate of growth, reproduction rate and average generational time were obtained, suggesting a rapid population growth under these rearing conditions. These findings permitted the creation of time models of survival and oviposition, as well as a quantitative estimate of the adaptation capacity of this species.

Life cycle and calculation of the intrinsic rate of natural increase of two bacterivorous nematodes, Panagrolaimus sp. and Poikilolaimus sp. from chemoautotrophic Movile Cave, Romania

Nematology ◽  
2007 ◽  
Vol 9 (2) ◽  
pp. 271-284 ◽  
Author(s):  
Daniel Muschiol ◽  
Walter Traunspurger
Keyword(s):  
Life Cycle ◽  
Body Length ◽  
Generation Time ◽  
Microbial Mats ◽  
Somatic Growth ◽  
Intrinsic Rate ◽  
Reproductive Rate ◽  
Natural Increase ◽  
Net Reproductive Rate ◽  
Movile Cave

AbstractThe life cycle and somatic growth of two bacterivorous nematodes, Panagrolaimus sp. and Poikilolaimus sp., isolated from chemoautotrophic microbial mats in Movile Cave, Romania, were studied in monoxenic cultures at 20°C with Escherichia coli as the food source. A method is described that allows simultaneous investigation of the somatic growth pattern, age-specific fecundity, and age-specific mortality of single individuals with high accuracy. Somatic growth curves of the species are presented. During juvenile development, both species showed a strict linear increase in body length, whereas body weight increased exponentially. Growth was continuous without lag phases. The relationships between fresh weight, W (μg), and body length, L (mm), were W = 1.6439L2.7672 for Poikilolaimus sp. and W = 0.2085L4.0915 for Panagrolaimus sp. Life tables and fecundity schedules for the two species are presented. In addition, demographic parameters were calculated. For Panagrolaimus, the intrinsic rate of natural increase (rm), calculated according to the Lotka equation, was 0.309, the net reproductive rate (R0) 64, the mean generation time (T) 13.8 days and the minimum generation time (Tmin) 9.5 days. The corresponding values for Poikilolaimus were rm = 0.165, R0 = 108, T = 26.2 and Tmin = 19.5. Panagrolaimus produced fewer progeny than Poikilolaimus during its life but exhibited faster population growth due to its faster maturation. It showed a distinct post-reproductive period, whereas Poikilolaimus remained fertile until death.

Past, Present and Future Population Growth and Urban Management in Zimbabwe

2018 ◽  
pp. 1197-1214
Author(s):  
Innocent Chirisa ◽  
Aaron Maphosa ◽  
Lazarus Zanamwe ◽  
Elmond Bandauko ◽  
Liaison Mukarwi
Keyword(s):  
Population Growth ◽  
Growth Rates ◽  
Urban Population ◽  
Urban Infrastructure ◽  
Natural Increase ◽  
Urban Migration ◽  
Urban Management ◽  
Population Growth Rates ◽  
Secondary Sources ◽  
Urban Population Growth

The central focus of this chapter is to analyse the urban population growth–urban management nexus in Zimbabwean cities. These cities are registering rapid population growth rates, due mainly to massive rural to urban migration and natural increase. Ideally, rapid urban population growth rates should be proportionate to urban infrastructure, facilities and services. This is not in the case in Zimbabwean cities, where the development of informal settlements, rising urban poverty, dilapidated urban infrastructure and other urban developmental challenges are rampant. Drawing from Malthusian theory, the current conditions in Zimbabwean cities represents that stage where the positive and negative checks are expected. In putting together this chapter, we used archival sources such as newspapers, government reports and other secondary sources. We conclude that planning initiatives and population control measures need to be used in Zimbabwean cities to address inefficiency and urban management challenges, which may be compromising urban sustainability. This study provides evidence-based information that urban local authorities may use to formulate policies to manage urban problems.

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