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 Life Tables of Two-Spotted Spider Mite Tetranychus urticae Koch (Acari: Tetranychidae) and its Predator Phytoseiulus persimilis Athias-Henriot (Acari: Phytoseiidae)

1970 ◽  
Vol 16 ◽  
pp. 1-10 ◽  
Author(s):  
M Fazlul Hoque ◽  
W Islam ◽  
M Khalequzzaman
Keyword(s):  
Tetranychus Urticae ◽  
Generation Time ◽  
Development Time ◽  
Phytoseiulus Persimilis ◽  
Reproductive Rate ◽  
Finite Capacity ◽  
Net Reproductive Rate ◽  
Wide Range ◽  
The Mean ◽  
Capacity For Increase

Life table of Tetranychus urticae and Phytoseiulus persimilis on bean leaflets were studied under laboratory conditions in three seasons. For T. urticae the development time from egg to adult varied from 7 to 24 days and the highest immature mortality was 78.70 % in winter. Eggs laid by females were 88.1 eggs in autumn and 70.6 eggs in summer season. The gross reproductive rate (GRR) was the highest (65.51) in autumn and 52.50 in summer. The net reproductive rate (Ro) was the highest (15.862) in autumn and 8.916 in summer. The intrinsic rates of increase (rm) and finite capacity for increase (λ) reached maximal values (0.1873 and 1.206) in autumn, whereas minimal values (0.056 and 1.058) were in winter season. The mean generation time (T) was the shortest in summer and double (3.701) days in autumn. The development time of P. persimilis from egg to adult varied from 5 to 14 days. The highest immature mortality was 60% in summer. Eggs laid by females were 39.4 eggs in autumn and 30.2 eggs in summer. The gross reproductive rate (GRR) was the highest (31.4) in autumn and 24.0 in summer. The net reproductive rate (Ro) was the highest (10.573) in autumn and 8.460 in winter. The intrinsic rates of increase (rm) and finite capacity for increase (λ) reached maximal values (0.1823 and 1.200) in summer, whereas minimal values (0.1025 and 1.108) were in winter. The mean generation time (T) was the shortest in summer. The results suggested that P. persimilis could develop and reproduce within a wide range of temperatures. Key words: Tetranychus urticae, Phytoseiulus persimilis, immature mortality, intrinsic rates of increase, reproductive rate, Survival  DOI:10.3329/jbs.v16i0.3733 J. bio-sci. 16: 1-10, 2008

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.

scholarly journals Phytophagy of the predator Podisus nigrispinus (Dallas, 1851) (Hemiptera: Pentatomidae) fed on prey and Brassicaceae

2017 ◽  
Vol 77 (4) ◽  
pp. 703-709 ◽  
Author(s):  
J. F. J. Grigolli ◽  
M. M. Kubota Grigolli ◽  
D. G. Ramalho ◽  
A. L. Martins ◽  
A. M. Vacari ◽  
...  
Keyword(s):  
Generation Time ◽  
Reproductive Rate ◽  
Egg Mass ◽  
Reproductive Parameters ◽  
Net Reproductive Rate ◽  
Laboratory Rearing ◽  
Males And Females ◽  
The Mean ◽  
Heteroptera Pentatomidae ◽  
Alternative Diet

Abstract The purpose of this study was to investigate the development and reproduction of the zoophytophagous predator Podisus nigrispinus (Dallas) (Heteroptera: Pentatomidae) fed kale, broccoli and cabbage affects its. Nymphs and adults of this predator were fed on larvae of Plutella xylostella (L.) (Lepidoptera: Plutellidae) as prey with kale, cabbage, or broccoli. In the nymph period, the duration and prey consumption were similar with all the Brassicacea cultivar. However, nymph viability was higher for predators with broccoli leaves. The mean weight of 5th-instar nymphs, newly emerged females and the sex ratio were similar among the Brassicacea cultivars, while newly emerged males were heavier with kale and broccoli leaves. The supply of broccoli leaves resulted in greater oviposition, higher number of eggs per egg mass and longer longevity of P. nigrispinus males and females. Furthermore, the consumption of P. xylostella larvae by adult predators was higher with these cultivars. The net reproductive rate (R0) and mean generation time (T) were highest for predators with prey and broccoli leaves. The reproductive parameters of P. nigrispinus were enhanced when fed on P. xylostella larvae with and broccoli leaves, which can be an alternative diet in laboratory rearing of this predator.

A demographic study of the life cycle of Tisbe furcata (Baird, 1837) (Copepoda: Harpacticoida)

1981 ◽  
Vol 61 (3) ◽  
pp. 691-705 ◽  
Author(s):  
Marc Bergmans
Keyword(s):  
Life Cycle ◽  
Generation Time ◽  
Harpacticoid Copepod ◽  
Intrinsic Rate ◽  
Reproductive Rate ◽  
Natural Increase ◽  
Net Reproductive Rate ◽  
Life Table Data ◽  
Table Data ◽  
Stable Stage

The life-cycle of the harpacticoid copepod Tisbe furcata (Baird, 1837) at 18 C was studied quantitatively. Stage durations were determined by two different methods, using synchronous cohorts. Combined nauplius stages last for 80·4 h; the successive copepodite stages take 23·0, 23·2, 28·0 (♀) to 23·2 (♂), 33·4 (♀) to 24·2 (♂) and 48·8 (♀) to 34·7 (♂) h, respectively. Females develop more slowly but more synchronously than males. Age-specific survival and fertility rates were used to calculate the stable stage distribution in an exponentially growing population. From life-table data the following demographic parameters were computed: intrinsic rate of natural increase rm = 0·233 day−1; net reproductive rate Ro = 94; minimum generation time Tmin = 14·9 days; parameters related to ‘generation time’: T = 19·5 days, = 16·4 days, Tc = 25·4 days.

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.

Development, survival and reproduction of a potential biological control agent, Lasioseius japonicus Ehara (Acari: Blattisociidae), on eggs of Drosophila melanogaster (Diptera: Drosophilidae) and Sitotroga cerealella (Lepidoptera: Gelechiidae)

2020 ◽  
Vol 25 (8) ◽  
pp. 1461-1471
Author(s):  
Lixia Xie ◽  
Na Zhang ◽  
Xinran Wu ◽  
Kai Liu ◽  
Chenlin Liu ◽  
...  
Keyword(s):  
Generation Time ◽  
Intrinsic Rate ◽  
Reproductive Rate ◽  
Intrinsic Rate Of Increase ◽  
Sitotroga Cerealella ◽  
Finite Rate ◽  
Net Reproductive Rate ◽  
Rate Of Increase ◽  
Survival And Reproduction ◽  
The Mean

Lasioseius japonicus is a species of soil-dwelling predatory mite with great potential for controlling insect pests and has a broad application prospect in biological control. This study was conducted under indoor conditions to explore the development, survival and reproduction of L. japonicus on two diets. Through the construction of two-sex life table of L. japonicus, it was revealed that, when it preyed on eggs of Drosophila melanogaster, the intrinsic rate of increase (r) was 0.2614 d-1, the net reproductive rate (R0) was 57.76 offspring, the finite rate of increase (λ) was 1.2988 d-1, and the mean generation time (T) was 15.49 d. When preying on eggs of Sitotroga cerealella, the intrinsic rate of increase (r) of L. japonicus was 0.1560 d-1, the net reproductive rate (R0) was 20.96 offspring, the finite rate of increase (λ) was 1.1690d-1, and the mean generation time (T) was 19.41 d. In addition, the life expectancy and population growth trend of L. japonicus were simulated based on the above two alternative prey species. The results showed that feeding on the eggs of D. melanogaster is more beneficial to the growth and reproduction of L. japonicus.

scholarly journals Statistik demografi Dolichotetranychus floridanus Banks pada dua kultivar nanas (Ananas comosus (L.) Merr.)

2021 ◽  
Vol 10 (4) ◽  
pp. 660-667
Author(s):  
Ariffatchur Fauzi ◽  
Sugeng Santoso ◽  
Ali Nurmansyah
Keyword(s):  
Life Cycle ◽  
Population Growth ◽  
Generation Time ◽  
Intrinsic Rate ◽  
Reproductive Rate ◽  
Ananas Comosus ◽  
Reproduction Rate ◽  
Fruit Crops ◽  
Net Reproductive Rate ◽  
Pest Infestation

Pineapple is one of important fruit crops in Indonesia. One of important problems in pineapple production is pest infestation.. This study aims to investigate the biology, demography, and life cycle of Dolichotetranychus floridanus Banks on two pineapple cultivars (Queen and Cayenne). Observation of mite development (eggs-adults) were conducted every 6 hours.  Adults were observed everyday to record the fecundity.  The life table was constructed from the survivor and fecundity of D. floridanus. Based on this table, the variables of population growth, including gross reproduction rate (GRR), net reproductive rate (R0), mean generation time (T) and increase intrinsic rate (r) were determined. The results showed that the GRR, R0, and r of D. floridanus in the Queen cultivar were higher than Cayenne cultivar, while the T in the Queen cultivar was lower. Queen cultivar more suitable for D. floridanus than Cayenne cultivar.

scholarly journals Biology and life table parameters of Metaphycus marensis Chirinos & Kondo, 2019, an encyrtid parasitoid of guava cottony scale in Venezuela

2020 ◽  
Vol 52 (1) ◽  
Author(s):  
D.T. Chirinos ◽  
R. Castro ◽  
J. Castro ◽  
I. Perez-Almeida ◽  
T. Kondo
Keyword(s):  
Life Cycle ◽  
Life Table ◽  
Generation Time ◽  
Field Experiments ◽  
Biological Control Agent ◽  
Reproductive Rate ◽  
Natural Increase ◽  
Type I ◽  
Life Table Parameters ◽  
Net Reproductive Rate

The guava cottony scale, Capulinia linarosae (Hemiptera: Eriococcidae) is an important pest of guava, Psidium guajava, in Venezuela and northern Colombia. Metaphycus marensis (Hymenoptera: Encyrtidae) is a new primary parasitoid species recently described associated with this pest. Studies were conducted on oogenesis, life cycle, survival, daily fecundity and life table parameters of Metaphycus marensis Chirinos & Kondo (Hymenoptera: Encyrtidae): intrinsic rate of natural increase (rm), generation time (T) and net reproductive rate (Ro). Females of M. marensis are synovigenic and this parasitoid goes through four larval instars and completes its life cycle in about 12.7 days. Survival was of type I, where mortality was initially detected by encapsulation of eggs and larvae. Metaphycus marensis was able to multiply its population 28.7 times (Ro) with rm of 0.242 in 13.9 days (T). The short generation time of the parasitoid in relation to its eriococcid host could represent a desirable attribute as a natural enemy. However, the low fecundity and the encapsulation by the host must be analyzed through field experiments in order to evaluate its effectiveness as a biological control agent for C. linarosae.

scholarly journals Tabel Hidup Nyamuk Vektor Filariasis Limfatik Culex quinquefasciatus (Diptera: Culicidae) di Laboratorium

2019 ◽  
Vol 18 (2) ◽  
pp. 73
Author(s):  
Tri Ramadhani ◽  
Vina Yuliani ◽  
Upik Kesumawati Hadi ◽  
Susi Soviana ◽  
Zubaidah Irawati
Keyword(s):  
Lymphatic Filariasis ◽  
Culex Quinquefasciatus ◽  
Generation Time ◽  
Control Program ◽  
Wuchereria Bancrofti ◽  
Reproductive Rate ◽  
Reproduction Rate ◽  
Net Reproductive Rate ◽  
Vector Control Program ◽  
Vector Borne

Latar belakang: Kelangsungan hidup nyamuk merupakan aspek yang penting dalam penularan penyakit tular vektor. Culex quinquefasciatus merupakan vektor filariasis limfatik yang disebabkan oleh wuchereria bancrofti. Pengetahuan kehidupan nyamuk berperan penting dalam keberhasilan program pengendalian vektor. Tujuan penelitian ini mendiskripsikan tabel hidup nyamuk Cx. quinquefasciatus di laboratorium.Metode: Penelitian diawali dengan koleksi larva Cx. quinquefasciatus di  Kota Pekalongan, kemudian diidentifikasi dan kolonisasi dalam kondisi laboratorium. Parameter yang diukur meliputi masa inkubasi, ekslosi, eksdisis, ketahanan hidup, laju reproduksi, waktu generasi dan laju pertumbuhan intrinsik.  Hasil: Cx. quinquefasciatus mempunyai siklus hidup 12.5 hari. Umur telur, larva, dan pupa masing-masing adalah 2.07; 10.2; dan  2.25 hari. Nyamuk jantan mempunyai ketahanan hidup yang lebih pendek dibandingkan betina. Laju reproduksi  bersih (Ro) sebesar 196.75, laju pertumbuhan intrinsik 0.35  dan waktu generasi (T) 14.91 hari.Simpulan: Pertumbuhan populasi Cx. quinquefasciatus  dapat diatur dan dikendalikan oleh kelulusan hidup dan mortalitas. ABSTRACTTitle: The Live Table of Vector Lymphatic Filariasis Culex quinquefasciatus (Diptera: Culicidae) in the LaboratoryBackground: The survival of a mosquito is an important aspect in the transmission of vector borne disease. Culex quinquefasciatus, which is a vector of lymphatic filariasis caused by wuchereria bancrofti. The knowledge of mosquito life is important in providing the foundation for the success of the vector control program. The research  aim to describe the life table Cx. quinquefasciatus in the laboratoryMethods:. This study was originated from the collecting larve  of Cx. quinquefasciatus from Pekalongan City, which were then identified and colonized under laboratory conditions. Parameters measured include the incubation period, ekslosi, eksdisis, survival rate, reproduction rate, and generation time.Results:The results showed that Cx. quinquefasciatus has a 12.5 day life cycle. Egg, larva, and pupa respectively were 2.07; 10.2; and 2.25 days. The males have a shorter survival period compared to  the  females. The net  reproductive  rate  (Ro)  was  196.75;  the  intrinsic  growth  rate  (rm)  was  0.35  and  the average generation time (T) was 14.91 days.Conclusion : The population growth of Culex quinquefasciatus can be regulated and controlled by life graduation and mortality 

scholarly journals THE LIFE TABLE OF Spodoptera pectinicornis Hampson AS BIOLOGICAL CONTROL AGENT OF WATER LETTUCE (Pistia stratiotes L.) WEED

2017 ◽  
Vol 3 (2) ◽  
pp. 7-13
Author(s):  
Lyswiana Aphrodyanti ◽  
Abdul Haris ◽  
Lidia Luisa Momongan
Keyword(s):  
Biological Control ◽  
Life Table ◽  
Generation Time ◽  
Biological Control Agent ◽  
Intrinsic Rate ◽  
Reproductive Rate ◽  
Control Agent ◽  
Water Lettuce ◽  
Net Reproductive Rate ◽  
Rate Of Growth

The table of life can provide information on birth (natality), death (mortality) and the opportunity to breed, so it can be used as a parameter of the behavior of population development.The purpose of this study was to determine the calculation of life table of S. pectinicornis Hampson as biological control agent of water lettuce (P. stratiotes) weed.The table of life is done by observing survival ability, mortality and fecundity of S. pectinicornis of a cohort of 300 eggs by looking at all the stages from egg, larva, pupa, and imago, and fecundity of female imago per day. The research was conducted in a condition of unlimited food resources and environment free of natural enemies. Parameters observed were gross reproductive rate (GRR), net reproductive rate (Ro), average of generation time (T), intrinsic rate of growth (r), and limited rate of growth (λ). The research result of the life table calculation showed that GRR value was 350.29, the value of net reproductive rate (Ro) was 19.59 descendants, the average of generation time (T) was 29.47 days, the value of intrinsic rate of accretion (r) was 0.10 and the value of limited rate of accretion (λ) was 1.11.

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