Effects of cadmium, mercury and lead on the survival and instantaneous rate of increase of Paronychiurus kimi (Lee) (Collembola)

2007 ◽  
Vol 35 (2) ◽  
pp. 404-411 ◽  
Author(s):  
Jino Son ◽  
Mun Il Ryoo ◽  
Jinho Jung ◽  
Kijong Cho
Keyword(s):  
Instantaneous Rate ◽  
Rate Of Increase

scholarly journals Hosts of Raoiella indica Hirst (Acari: Tenuipalpidae) Native to the Brazilian Amazon

2017 ◽  
Vol 9 (4) ◽  
pp. 86 ◽  
Author(s):  
Cristina A. Gómez-Moya ◽  
Talita P. S. Lima ◽  
Elisângela G. F. Morais ◽  
Manoel G. C. Gondim Jr. ◽  
Gilberto J. De Moraes
Keyword(s):  
Plant Species ◽  
Native Species ◽  
Brazilian Amazon ◽  
Intrinsic Rate Of Increase ◽  
Native Plant ◽  
Instantaneous Rate ◽  
Net Reproductive Rate ◽  
Musa Paradisiaca ◽  
Rate Of Increase ◽  
Raoiella Indica

The expansion of red palm mite (RPM), Raoiella indica (Acari: Tenuipalpidae) in Brazil could impact negatively the native plant species, especially of the family Arecaceae. To determine which species could be at risk, we investigated the development and reproductive potential of R. indica on 19 plant species including 13 native species to the Brazilian Amazon (12 Arecaceae and one Heliconiaceae), and six exotic species, four Arecaceae, a Musaceae and a Zingiberaceae. Values of the instantaneous rate of increase (ri) were initially estimated at 7, 14, 21 and 28 days after infestation of each species. Higher values of ri (> 0.05) were determined on the Arecaceae Adonidia merrillii, Astrocaryum jauari, Cocos nucifera, Bactris simplicifrons, Mauritia flexuosa, Phoenix dactylifera and Socratea exorrhiza, and on the Heliconiaceae Heliconia psittacorum Sassy; these were classified as “potential primary hosts”. Lower, but still positive values of ri (0-0.05) were determined on the Arecaceae Bactris maraja, Oenocarpus bacaba, Oenocarpus bataua and on the Musaceae Musa × paradisiaca (Prata variety); these were classified as “potential secondary hosts”. Negative values of ri were determined for the remaining plants, i.e., the Arecaceae Astrocaryum aculeatum, Attalea maripa, Bactris gasipaes, Elaeis guineensis, Euterpe oleracea, Euterpe precatoria, and the Zingiberaceae Alpinia rosea; these were considered “non-hosts”. Species with ri < 0.05 were considered not to be threatened by the RPM. Biological parameters of RPM were evaluated on the plant species with positive ri (except B. maraja) and two native species with negative ri (E. oleracea and E. precatoria). Mean developmental time ranged from 14.7 days on C. nucifera to 21.4 days on Musa × paradisiaca, showing a significant influence of the plant substrate. Immature viability, oviposition rate, net reproductive rate (R0) and intrinsic rate of increase (rm) were affected by the plant species.

Acaricidal activity and sublethal effects of the microbial pesticide spinosad on Tetranychus urticae (Acari: Tetranychidae)

2017 ◽  
Vol 22 (10) ◽  
pp. 1748 ◽  
Author(s):  
Irena Međo ◽  
Bojan Stojnić ◽  
Dejan Marčić
Keyword(s):  
Population Growth ◽  
Tetranychus Urticae ◽  
Sublethal Effects ◽  
Intrinsic Rate ◽  
Intrinsic Rate Of Increase ◽  
Instantaneous Rate ◽  
Leaf Discs ◽  
Rate Of Increase ◽  
Female Longevity ◽  
Microbial Pesticide

Laboratory bioassays were conducted to evaluate the toxicity of the microbial pesticide spinosad to different life stages of the two-spotted spider mite, Tetranychus urticae Koch, as well as its sublethal effects on reproduction and population growth of this important mite pest. The biopesticide was applied to bean primary leaves or leaf discs carrying spider mites using a Potter spray tower (2.7 mg/cm2 aqueous deposit). The following LC50 and LC90 (mg/L) estimates for motile stages were obtained in acute toxicity bioassays: 27.52 and 116.72 (larvae), 36.55 and 136.20 (protonymphs), 82.76 and 721.28 (female deutonymphs), and 61.47 and 457.21 (adult females). Spinosad showed no significant ovicidal action: toxic effect observed after spraying eggs (LC50 = 105.78 mg/L, LC90 = 596.95 mg/L) was the result of its residual action on larvae that hatched from the treated eggs. The effects of spinosad on life history traits and population growth of adult female survivors from treatments with 240, 120 and 60 mg/L were evaluated in two successive 7-day bioassays on untreated leaf discs. In the first bioassay, females that survived treatments as 24 h old eggs and completed their juvenile development on treated leaves had significantly lower gross fecundity, net fecundity and instantaneous rate of increase (ri) but the reduction was merely 4–6%, 9–11%, and 2–3%, respectively. Female longevity was significantly reduced (approximately by half a day) only after treatment with 240 mg/L. In the second bioassay, in which females were treated during their pre-ovipositional period, the treatments with 240 and 120 mg/L significantly reduced their gross fecundity (16–17%), net fecundity (28–31%), ri values (8–9%) and female longevity (approximately by one day). Spinosad effects on the intrinsic rate of increase (rm) and other demographic parameters were evaluated in two successive bioassays in which life tables were constructed for females that survived treatment with 120 mg/L at the egg stage (first demographic bioassay) or pre-ovipositional period (second demographic bioassay). In the first bioassay, the intrinsic rate of increase was significantly higher in treated (rm = 0.278) than control mites (rm = 0.267) as a result of higher net fertility at the beginning of reproduction of treated females. In the second bioassay, treated females had significantly lower rm than control females (0.254 and 0.283, respectively). The results obtained in this study indicate that spinosad, applied against insect pests (at field relevant rates of 60–240 mg/L), could eliminate a part of T. urticae population as well, but survivors would retain a significant potential for population recovery. 

Demographic analysis of gummy shark (Mustelus antarcticus) and school shark (Galeorhinus galeus) off southern Australia by applying a generalized Lotka equation and its dual equation

2000 ◽  
Vol 57 (1) ◽  
pp. 214-222 ◽  
Author(s):  
Yongshun Xiao ◽  
Terence I Walker
Keyword(s):  
Total Mortality ◽  
Intrinsic Rate ◽  
Fish Population ◽  
Intrinsic Rate Of Increase ◽  
Demographic Analysis ◽  
Instantaneous Rate ◽  
Dual Equation ◽  
Population Dynamics Model ◽  
Rate Of Increase ◽  
Galeorhinus Galeus

Although Lotka's equation is commonly used for calculating the intrinsic rate of increase with time of a fish population in demographic analysis, its dual equation has never been derived. In this paper, we establish an explicit relationship between the intrinsic rate of increase with time of a fish population and its instantaneous rate of natural mortality from an age-dependent population dynamics model, derive a generalized Lotka equation for calculating the intrinsic rate of increase with time, and derive its dual equation for calculating the intrinsic rate of decrease with age. The virginal intrinsic rate of increase with time of the gummy shark (Mustelus antarcticus) population was calculated as 0.115957·year-1 and its intrinsic rate of decrease with age as -0.312957·year-1. The virginal intrinsic rate of increase with time of the school shark (Galeorhinus galeus) population was calculated as 0.109480·year-1 and its intrinsic rate of decrease with age as -0.216980·year-1. The generalized Lotka equation and its dual equation thus derived imply that both reproductive schedules of a population of animals and its instantaneous rate of total mortality determine its intrinsic rate of increase with time, whereas its reproductive schedules alone determine its intrinsic rate of decrease with age.

An experimental study of declining populations

2005 ◽  
Vol 32 (6) ◽  
pp. 481 ◽  
Author(s):  
Jim Hone ◽  
the late Graeme Caughley ◽  
David Grice
Keyword(s):  
Experimental Study ◽  
Population Decline ◽  
Experimental Studies ◽  
Theoretical Models ◽  
Second Phase ◽  
Population Declines ◽  
Negative Effects ◽  
Instantaneous Rate ◽  
Rate Of Increase ◽  
Declining Populations

Wildlife population declines have been attributed to predation, habitat change, and other agents of decline. An experimental study applied predation (at three levels) and habitat (at two levels) treatments over two years and measured the patterns of decline of populations of a medium-sized mammal (European rabbits). A model of population dynamics and effects of the treatments predicted negative effects of both treatments and an interaction of the treatments. All populations declined during the study including the experimental controls. During the first seven months (first phase of the study) the rate of decline, as estimated by the observed monthly instantaneous rate of increase (r), was more negative (P < 0.05) with increasing predation levels but there was no effect (P > 0.05) of habitat manipulation on r. There were no significant effects of treatments on rabbit abundance, or density, during the first phase of the study. During the second phase of the study, of 12 months’ duration, there were no significant (P > 0.05) effects of treatments on rabbit abundance, density, or r. There were no significant (P > 0.05) interactions of treatments on any response variable during either phase of the study. The interaction predicted by the theoretical model was not supported. Estimated abundance at the end of the study was not related (P > 0.05) to initial abundance (correlation = 0.023). The implications of the results are that such experimental studies can be used to evaluate theoretical models, though such studies may require a larger number of treatment replicates, and treatments at more extreme levels, to more clearly detect the effects of agents of population decline and their interactions.

Residual and sublethal effects of fenpyroximate and pyridaben on the instantaneous rate of increase of Tetranychus urticae

2006 ◽  
Vol 25 (6) ◽  
pp. 542-548 ◽  
Author(s):  
Minsik Kim ◽  
Cheolho Sim ◽  
Dongyoung Shin ◽  
Eunho Suh ◽  
Kijong Cho
Keyword(s):  
Tetranychus Urticae ◽  
Sublethal Effects ◽  
Instantaneous Rate ◽  
Rate Of Increase

scholarly journals Acute toxity and sublethal effects of pymetrozine on the whitefly parasitoid Encarsia formosa Gahan

2020 ◽  
Vol 35 (2) ◽  
pp. 81-95
Author(s):  
Tanja Drobnjakovic ◽  
Dejan Marcic
Keyword(s):  
Sublethal Effects ◽  
Integrated Control ◽  
Pupal Stage ◽  
Adult Emergence ◽  
Encarsia Formosa ◽  
Greenhouse Whitefly ◽  
Instantaneous Rate ◽  
Rate Of Increase ◽  
Juvenile Development ◽  
Total Parasitism

Sublethal effects of a pymetrozine-based product (commercial product Chess 50 WP) on life history traits and population growth of one commercialized strain (?Dutch? strain) and two local populations (Bujanovac and Negotin) of the whitefly parasitoid Encarsia formosa Gahan (Hymenoptera: Aphelinidae) were evaluated in laboratory bioassays. All trials were carried out at 27?1?C temperature and under 60?10 % relative humidity and 16/8 h daylight/darkness photoperiod in four replications. Longevity of wasps exposed for 48 h to residues of the pymetrozine insecticide (LC50, 280 mg a.i./l) was shorter (by 2.7-3 days) than that of control wasps. Total parasitism of Negotin wasps was significantly reduced (by 8.2 %), as well as total parasitism and adult emergence of the Dutch strain (by 7.3 and 8.2 %, respectively), compared to control wasps. The instantaneous rate of increase (ri) of surviving adult wasps was also significantly reduced (by 6.6, 6.3 and 7.6 % in populations Negotin, Bujanovac and Dutch strain, respectively). Direct treatment of wasps at their pupal stage (LC50, 300 mg a.i./l) reduced total parasitism of Negotin wasps (by 8 %), and reduced ri levels, but the reduction was significant only for the Bujanovac (by 6.7 %) and Negotin (by 4.6 %) populations. Juvenile development of the parasitoid in treated pupae was significantly extended (by 0.3-1.1 days), compared to control wasps. The implications of these results on integrated control of the greenhouse whitefly are discussed.

scholarly journals The effect of spiromesifen on the reproductive potential of Tetranychus urticae koch (Acari: Tetranychidae)

2009 ◽  
Vol 24 (3) ◽  
pp. 203-209 ◽  
Author(s):  
Dejan Marcic ◽  
Irena Ogurlic ◽  
Slavka Mutavdzic ◽  
Pantelija Peric
Keyword(s):  
Tetranychus Urticae ◽  
Sublethal Effects ◽  
Reproductive Potential ◽  
Instantaneous Rate ◽  
Control Value ◽  
Rate Of Increase ◽  
Significant Difference ◽  
L 51 ◽  
Two Spotted Spider Mite ◽  
Tetranychus Urticae Koch

Laboratory bioassays were conducted to evaluate the effects of spiromesifen on the fecundity, fertility and population growth of two-spotted spider mite (Tetranychus urticae Koch) after treatment of pre-ovipositing females with five acaricide concentrations: 180 mg/l (maximum recommended concentration for use in glasshouses against spider mites), 18 mg/l, 1.8 mg/l and 0.18 mg/l (the last one was discriminative for eggs and immatures in preliminary studies, i.e. produced 100% mortality of those stages) and 0.018 mg/l. After 24h exposure, the percentages of females surviving treatment without visible symptoms of poisoning were 50% (180 mg/l), 45% (18 mg/l), 51% (1.8 mg/l), 74% (0.18 mg/l), 96% (0.018 mg/l) and 98% (0 mg/l). Over the first four days after treatment, the females that survived 180 mg/l and 18 mg/l laid no eggs. The total number of eggs laid after treatment with these two concentrations was reduced to less than 2% against the control by the end of the trial. The females that survived 1.8 mg/l laid 50% less eggs, compared to the control, while the number of eggs laid by the females treated with 0.18 mg/l and 0.018 mg/l were 19% and 4% lower, respectively. Over the initial four days, egg hatch rates in treatments were 73-87%, and 92-93% in the control. Significant statistical differences between gross fecundity (FCg) and gross fertility (FTg) values in the control and treatments were detected for females surviving 180 mg/l, 18 mg/l and 1.8 mg/l. On the other hand, only the net fertility (FTn) value of females treated with 0.018 mg/l showed no statistically significant difference from the control value. Treatments with 180 mg/l and 18 mg/l significantly reduced the instantaneous rate of increase (ri) 6, 8 and 10 days after treatment, compared to the control. The negative ri values in those treatments indicated a declining population. Sublethal effects of spiromesifen and its impact on T. urticae management are discussed.

scholarly journals The role of predation in the decline and extirpation of woodland caribou

2020 ◽  
Author(s):  
Heiko Wittmer ◽  
ARE Sinclair ◽  
BN McLellan
Keyword(s):  
Rangifer Tarandus ◽  
Population Decline ◽  
Temporal Distribution ◽  
Pregnancy Rates ◽  
Foraging Habitat ◽  
Woodland Caribou ◽  
Instantaneous Rate ◽  
Population Growth Rates ◽  
Rate Of Increase ◽  
Winter Foraging

To select appropriate recovery strategies for endangered populations, we must understand the dynamics of small populations and distinguish between the possible causes that drive such populations to low numbers. It has been suggested that the pattern of population decline may be inversely density-dependent with population growth rates decreasing as populations become very small; however, empirical evidence of such accelerated declines at low densities is rare. Here we analyzed the pattern of decline of a threatened population of woodland caribou (Rangifer tarandus caribou) in British Columbia, Canada. Using information on the instantaneous rate of increase relative to caribou density in suitable winter foraging habitat, as well as on pregnancy rates and on causes and temporal distribution of mortalities from a sample of 349 radiocollared animals from 15 subpopulations, we tested 3 hypothesized causes of decline: (a) food regulation caused by loss of suitable winter foraging habitat, (b) predation-sensitive foraging caused by loss of suitable winter foraging habitat and (c) predation with caribou being secondary prey. Population sizes of caribou subpopulations ranged from <5 to >500 individuals. Our results showed that the rates of increase of these subpopulations varied from -0.1871 to 0.0496 with smaller subpopulations declining faster than larger subpopulations. Rates of increase were positively related to the density of caribou in suitable winter foraging habitat. Pregnancy rates averaged 92.4% ±2.24 and did not differ among subpopulations. In addition, we found predation to be the primary cause of mortality in 11 of 13 subpopulations with known causes of mortality and predation predominantly occurred during summer. These results are consistent with predictions that caribou subpopulations are declining as a consequence of increased predation. Recovery of these woodland caribou will thus require a multispecies perspective and an appreciation for the influence of inverse density dependence on population trajectories. © Springer-Verlag 2005.

Seasonal Abundance and Population Flux of Tigriopus Californicus (Copepoda: Harpacticoida) in Barkley Sound, British Columbia

1998 ◽  
Vol 78 (2) ◽  
pp. 467-481 ◽  
Author(s):  
James J. Powlik
Keyword(s):  
Natural Populations ◽  
Seasonal Abundance ◽  
Instantaneous Rate ◽  
Female Ratio ◽  
Tigriopus Californicus ◽  
Mature Adults ◽  
Barkley Sound ◽  
A Value ◽  
Rate Of Increase ◽  
Male To Female

The study describes the seasonal density and age structure for splashpool metapopulations of Tigriopus californicus (Copepoda: Harpacticoida). Natural populations were highly variable, ranging from 217 ± 401·7 ind 1−1 in winter (mean ± SE) to 835 ± 1750·6 ind 1−1 in summer, with some populations approaching 20,000 ind 1−1 in all seasons except winter. Male-to-female ratio ranged from 1·36 in spring and summer to 1·84 in autumn, and reproduction was observed throughout the year. Nauplii abundance averaged 28 + 7·4 ind 11, a value much lower than expected for in situ copepod populations and possibly due to behavioural processes such as cannibalism and inhibition of egg deposition. The densest assemblages of splashpool microcrustacea were almost entirely T. californicus, principally mature adults and including clasped male-female pairs and ovigerous females. A simple population growth model is presented, along with parameters for calculating the instantaneous rate of increase, birth, and death in the absence of disturbance.

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