The method developed by Wyatt and White (1977) was applied to calculate the intrinsic rates of increase for parasitoids based on 23 fecundity data sets from the literature. The studies showed that there existed the li...The method developed by Wyatt and White (1977) was applied to calculate the intrinsic rates of increase for parasitoids based on 23 fecundity data sets from the literature. The studies showed that there existed the linear relationship between the accurate values of rm and In f (Md) / d or In (A/d/2) / d, that is, 1) rm= 0.845 In (Md) / d or 2) rm= 0.880 In (Md/ 2) / d. Where d is the prereproductive time, Md is the number of female offspring produced per original female from the first to the dthday of reproduction, and Md/2 is the number of female offspring produced per original female from the first to the (d/ 2) th day of reproduction. These equations can provide the accurate estimates of rm for parasitoids in this study. The approach is advantageous because it does not require the construction of detailed fecundity tables for estimating parasitoid rates of increase. Of course, whether these equations are appropriate for the other taxa will need to be further studied.展开更多
This paper deals with the validation and theoretical analyses of a simple method for calculating the intrinsic rate of increase, rm, of aphids and mites. This method does not require a detailed fecundity table data. T...This paper deals with the validation and theoretical analyses of a simple method for calculating the intrinsic rate of increase, rm, of aphids and mites. This method does not require a detailed fecundity table data. The value of rm can be estimated by the simple equation: rm=0.74ln (Md)/d, where d is the time from birth to first reproduction; Md is the number of female offspring produced per original female in 2d. This method was developed by Wyatt and White. We reached the following conclusions from our study: When the parameter, Md is less than 1, this equation is not appropriate for estimating rm of populations; When the parameter, Md is larger than 1 and about 70% or more of the reproductive contribution to the rm is achieved in 2d, the equation is appropriate for calculatng the rm of aphids and mites.As Md decreases, the required reproductive contribution to the rm in 2d corresponding to the constant 0.74 will increase. However, whether 70% or more of reproductive contribution to rm is achieved in 2d still is a problem for whole taxa of aphids and mites. Therefore, further siudy on reproductive distribution will be required for practical application of this method.展开更多
The Pacific saury(Cololabis saira)is one of the major harvested species in the temperate waters of the northwestern Pacific Ocean(NPO).The Catch-MSY model uses catch data and basic life history information to estimate...The Pacific saury(Cololabis saira)is one of the major harvested species in the temperate waters of the northwestern Pacific Ocean(NPO).The Catch-MSY model uses catch data and basic life history information to estimate the Maximum Sustainable Yield(MSY)for data-limited fisheries.Since there is considerable uncertainty in the current status of the Pacific saury stock in the NPO,the Catch-MSY model was used in this study to estimate MSY on the basis of catch data and life history information from the North Pacific Fisheries Commission(NPFC).During the process,17 scenarios,according to different prior distributions of the intrinsic rate of increase(r)and carrying capacity(K),were set for sensitivity analysis.Moreover,the influence of different catch time series and different process errors were taken into account.The results show the following:(1)there was a strong negative correlation relationship between ln(r)and ln(K);the MSY increases with an increase in the lower limit of r;(2)The time series of catch data had a limited impact on the assessment results,whereas the results of the model were sensitive to the annual catch in the first and last years;(3)The estimated MSYs of the Pacific saury were 47.37×10^4 t(41.57×10^4 t to 53.17×10^4 t)in scenario S1A and 47.53×10^4 t(41.79×10^4 t to 53.27×10^4 t)in scenario S1B.Given the uncertainty of the Catch-MSY model,maintaining a management target between 50×10^4 t and 70×10^4 t was a better management regulation.This study shows that the Catch-MSY model is a useful choice for estimating the MSY of data-limited species such as the Pacific saury.展开更多
Most fisheries in China do not have maximum sustainable yield（MSY） estimates due to limited and poor data.Therefore, finding a common method to estimate MSY or total allowable catch（TAC） for fishery management is ...Most fisheries in China do not have maximum sustainable yield（MSY） estimates due to limited and poor data.Therefore, finding a common method to estimate MSY or total allowable catch（TAC） for fishery management is necessary. MSYs of three important fisheries in the East China Sea were evaluated through a catch-based model.Estimates for intrinsic rate of increase（r） and five levels of process error were considered. Results showed hairtail Trichiurus japonicas（Temminck and Schlegel） and small yellow croaker Larimichthys polyactis（Bleeker） fisheries experienced overfishing from the mid-1990 s to the early 2000 s, and the suggested TACs were 55.8×10^4 t and9.06×10^4 t, respectively. Decades of overfishing in wintering and spawning grounds of large yellow croaker Larimichthys crocea（Richardson） caused the fishery＇s collapse in the 1980 s, and it has not recovered until today.The Catch–MSY model generated similar estimated MSYs with other methods and may be a useful choice for the assessment of regional stocks in China.展开更多
Two-spotted spider mite, Tetranychus urticae Koch, is one of the important pests of bean, which can cause severe damages on it. Silicon is one of the micronutrient elements, as its spray on the leaves can decrease the...Two-spotted spider mite, Tetranychus urticae Koch, is one of the important pests of bean, which can cause severe damages on it. Silicon is one of the micronutrient elements, as its spray on the leaves can decrease the population of the pest. In this research, the impact of four different doses of Si (0, 1, 1/5, 2 ppm) was investigated on biological and population growth parameters of T. urticae. The experiments were carried out in Petri dishes in an incubator at 25°C ± 2°C, 65% ± 5% RH and 16 L: 8 D. The duration of developmental stage was significantly affected by Si dose. The longest immature period, the shortest longevity of females and the shortest oviposition period were obtained at 2 ppm. In addition, Si dose significantly affected population growth parameters of the mite. The intrinsic rate of natural increase (rm) of the mite ranged from 0.246 to 0.215 day which lowest and the highest values were at 2 ppm and control plants, respectively. The lowest net reproductive rate (R0) and finite rate of increase (λ) of the mite and the highest value of mean generation time (T) and doubling time (DT) were estimated at 2 ppm. The results of this peruse represented that 2 ppm had better potential for decreasing the population of the two-spotted spider mite, and it can be used in the mite integrated pest management programs.展开更多
Reproduction and population parameters of vegetable leafminer, Liriomyza sativae Blanchard were measured on cucumber （Cucumis sativus L.） at seven constant temperatures （10, 15, 20, 25, 30, 35 and 40℃）. No eggs w...Reproduction and population parameters of vegetable leafminer, Liriomyza sativae Blanchard were measured on cucumber （Cucumis sativus L.） at seven constant temperatures （10, 15, 20, 25, 30, 35 and 40℃）. No eggs were found at 10℃ and flies died after exposure to 40℃. The significantly highest intrinsic rate of natural increase （rm）, net reproductive rate （R0） and finite rate of increase （λ） ofL. sativae were obtained at 25℃ as 0.196, 52.452, and 1.216, respectively. The above-mentioned parameters decreased at 15℃ and 135℃ and this reduction at 35℃ was strong. Doubling time （DT） varied significantly with temperature. The shortest doubling time was obtained at 25℃. Mean generation time （T） decreased significantly with increasing temperature between 15℃ and 35℃. Percentage of immature ages in the stable age distribution was more than 95% at all temperatures. Female longevity was greater than male at all temperatures. Liriomyza sativae lived for a long time at 15℃, whereas at 35℃ had lower survival rates. The effect of temperature on reproduction, especially the intrinsic rate of increase of L. sativae would be useful for predicting its longterm population fluctuation over several generations.展开更多
文摘The method developed by Wyatt and White (1977) was applied to calculate the intrinsic rates of increase for parasitoids based on 23 fecundity data sets from the literature. The studies showed that there existed the linear relationship between the accurate values of rm and In f (Md) / d or In (A/d/2) / d, that is, 1) rm= 0.845 In (Md) / d or 2) rm= 0.880 In (Md/ 2) / d. Where d is the prereproductive time, Md is the number of female offspring produced per original female from the first to the dthday of reproduction, and Md/2 is the number of female offspring produced per original female from the first to the (d/ 2) th day of reproduction. These equations can provide the accurate estimates of rm for parasitoids in this study. The approach is advantageous because it does not require the construction of detailed fecundity tables for estimating parasitoid rates of increase. Of course, whether these equations are appropriate for the other taxa will need to be further studied.
文摘This paper deals with the validation and theoretical analyses of a simple method for calculating the intrinsic rate of increase, rm, of aphids and mites. This method does not require a detailed fecundity table data. The value of rm can be estimated by the simple equation: rm=0.74ln (Md)/d, where d is the time from birth to first reproduction; Md is the number of female offspring produced per original female in 2d. This method was developed by Wyatt and White. We reached the following conclusions from our study: When the parameter, Md is less than 1, this equation is not appropriate for estimating rm of populations; When the parameter, Md is larger than 1 and about 70% or more of the reproductive contribution to the rm is achieved in 2d, the equation is appropriate for calculatng the rm of aphids and mites.As Md decreases, the required reproductive contribution to the rm in 2d corresponding to the constant 0.74 will increase. However, whether 70% or more of reproductive contribution to rm is achieved in 2d still is a problem for whole taxa of aphids and mites. Therefore, further siudy on reproductive distribution will be required for practical application of this method.
基金Supported by the National Sci-Tech Support Plan“Fishing Technology and New Resources in Oceanic Fisheries”(No.2013BAD13B05)。
文摘The Pacific saury(Cololabis saira)is one of the major harvested species in the temperate waters of the northwestern Pacific Ocean(NPO).The Catch-MSY model uses catch data and basic life history information to estimate the Maximum Sustainable Yield(MSY)for data-limited fisheries.Since there is considerable uncertainty in the current status of the Pacific saury stock in the NPO,the Catch-MSY model was used in this study to estimate MSY on the basis of catch data and life history information from the North Pacific Fisheries Commission(NPFC).During the process,17 scenarios,according to different prior distributions of the intrinsic rate of increase(r)and carrying capacity(K),were set for sensitivity analysis.Moreover,the influence of different catch time series and different process errors were taken into account.The results show the following:(1)there was a strong negative correlation relationship between ln(r)and ln(K);the MSY increases with an increase in the lower limit of r;(2)The time series of catch data had a limited impact on the assessment results,whereas the results of the model were sensitive to the annual catch in the first and last years;(3)The estimated MSYs of the Pacific saury were 47.37×10^4 t(41.57×10^4 t to 53.17×10^4 t)in scenario S1A and 47.53×10^4 t(41.79×10^4 t to 53.27×10^4 t)in scenario S1B.Given the uncertainty of the Catch-MSY model,maintaining a management target between 50×10^4 t and 70×10^4 t was a better management regulation.This study shows that the Catch-MSY model is a useful choice for estimating the MSY of data-limited species such as the Pacific saury.
基金The National Natural Science Foundation of China under contract No.31602157the Special Fund for Agroscientific Research in the Public Interest under contract No.201403008the Central Public-interest Scientific Institution Basal Research Fund of South China Sea Fisheries Research Institute under contract No.2016TS06
文摘Most fisheries in China do not have maximum sustainable yield（MSY） estimates due to limited and poor data.Therefore, finding a common method to estimate MSY or total allowable catch（TAC） for fishery management is necessary. MSYs of three important fisheries in the East China Sea were evaluated through a catch-based model.Estimates for intrinsic rate of increase（r） and five levels of process error were considered. Results showed hairtail Trichiurus japonicas（Temminck and Schlegel） and small yellow croaker Larimichthys polyactis（Bleeker） fisheries experienced overfishing from the mid-1990 s to the early 2000 s, and the suggested TACs were 55.8×10^4 t and9.06×10^4 t, respectively. Decades of overfishing in wintering and spawning grounds of large yellow croaker Larimichthys crocea（Richardson） caused the fishery＇s collapse in the 1980 s, and it has not recovered until today.The Catch–MSY model generated similar estimated MSYs with other methods and may be a useful choice for the assessment of regional stocks in China.
文摘Two-spotted spider mite, Tetranychus urticae Koch, is one of the important pests of bean, which can cause severe damages on it. Silicon is one of the micronutrient elements, as its spray on the leaves can decrease the population of the pest. In this research, the impact of four different doses of Si (0, 1, 1/5, 2 ppm) was investigated on biological and population growth parameters of T. urticae. The experiments were carried out in Petri dishes in an incubator at 25°C ± 2°C, 65% ± 5% RH and 16 L: 8 D. The duration of developmental stage was significantly affected by Si dose. The longest immature period, the shortest longevity of females and the shortest oviposition period were obtained at 2 ppm. In addition, Si dose significantly affected population growth parameters of the mite. The intrinsic rate of natural increase (rm) of the mite ranged from 0.246 to 0.215 day which lowest and the highest values were at 2 ppm and control plants, respectively. The lowest net reproductive rate (R0) and finite rate of increase (λ) of the mite and the highest value of mean generation time (T) and doubling time (DT) were estimated at 2 ppm. The results of this peruse represented that 2 ppm had better potential for decreasing the population of the two-spotted spider mite, and it can be used in the mite integrated pest management programs.
文摘Reproduction and population parameters of vegetable leafminer, Liriomyza sativae Blanchard were measured on cucumber （Cucumis sativus L.） at seven constant temperatures （10, 15, 20, 25, 30, 35 and 40℃）. No eggs were found at 10℃ and flies died after exposure to 40℃. The significantly highest intrinsic rate of natural increase （rm）, net reproductive rate （R0） and finite rate of increase （λ） ofL. sativae were obtained at 25℃ as 0.196, 52.452, and 1.216, respectively. The above-mentioned parameters decreased at 15℃ and 135℃ and this reduction at 35℃ was strong. Doubling time （DT） varied significantly with temperature. The shortest doubling time was obtained at 25℃. Mean generation time （T） decreased significantly with increasing temperature between 15℃ and 35℃. Percentage of immature ages in the stable age distribution was more than 95% at all temperatures. Female longevity was greater than male at all temperatures. Liriomyza sativae lived for a long time at 15℃, whereas at 35℃ had lower survival rates. The effect of temperature on reproduction, especially the intrinsic rate of increase of L. sativae would be useful for predicting its longterm population fluctuation over several generations.
