Delphastus catalinae and Serangium japonicum are the important natural enemies of Bemisia tabaci,of which,the former is exotic,and the latter is indigenous.In this paper,the influence of interspecies competition on th...Delphastus catalinae and Serangium japonicum are the important natural enemies of Bemisia tabaci,of which,the former is exotic,and the latter is indigenous.In this paper,the influence of interspecies competition on the population growth of D.catalinae and S.japonicum was studied under conditions of single and mixed rearing,and Lotka-Volterra equation was used to simulate the competition when more and less preys provided for the two ladybirds.The results showed that the population growth of D.catalinae was greater than that of S.japonicum when single rearing,and the population growth of S.japonicum was greater than that of D.catalinae when mixed rearing.In the competition system of the two ladybirds,S.japonicum was dominant,while D.catalinae could exist simultaneously.展开更多
The ladybeetle, Delphastus catalinae (Horn), is one of the most commonly usedpredacious natural enemies being commercially reared for controlling whiteflies, including Bemisiatabaci (Gennadius) biotype B (= B. argenti...The ladybeetle, Delphastus catalinae (Horn), is one of the most commonly usedpredacious natural enemies being commercially reared for controlling whiteflies, including Bemisiatabaci (Gennadius) biotype B (= B. argentifolii Bellows and Perring), on various ornamental andvegetable crops under greenhouse conditions. The development, survivorship, and fecundity of D.catalinae feeding on B. tabaci biotype B on collard plants were determined in the laboratory, andthe age-specific life table parameters were analyzed based on the life history data. Developmentaltime was 4.0,1.9,1.1,1.4,5.2, and 5.3 days for eggs, first, second, third, fourth instars, andpupae, respectively, with an average of 18.9 days from oviposition to adult emergence for bothsexes, 19.0 days for females, and 18.8 days for males. Adult longevities averaged 146.6 days forboth sexes, 122.6 days for females, and 170.5 days for males. After an average 4.9 dayspreoviposition period, females laid a mean of 5.6 eggs per day over a 97.0-day period. Netreproductive rate (R_0) and gross reproductive rate (Σm_x) were estimated by life table analysis at276.8 and 325.1, respectively. Generation time (T) and doubling time (DT) were 35.6 and 4.8 daysrespectively, and the intrinsic rate of natural population increase (r_m) was estimated at 0.158, orl= 1.171 for the finite rate of increase. The r_m value of D. catalinae is similar to or higherthan those of the whitefly feeding on most vegetable and ornamental crops, indicating that theladybeetle is capable of regulating populations of B. tabaci biotype B and other whiteflies undergreenhouse conditions.展开更多
文摘Delphastus catalinae and Serangium japonicum are the important natural enemies of Bemisia tabaci,of which,the former is exotic,and the latter is indigenous.In this paper,the influence of interspecies competition on the population growth of D.catalinae and S.japonicum was studied under conditions of single and mixed rearing,and Lotka-Volterra equation was used to simulate the competition when more and less preys provided for the two ladybirds.The results showed that the population growth of D.catalinae was greater than that of S.japonicum when single rearing,and the population growth of S.japonicum was greater than that of D.catalinae when mixed rearing.In the competition system of the two ladybirds,S.japonicum was dominant,while D.catalinae could exist simultaneously.
文摘The ladybeetle, Delphastus catalinae (Horn), is one of the most commonly usedpredacious natural enemies being commercially reared for controlling whiteflies, including Bemisiatabaci (Gennadius) biotype B (= B. argentifolii Bellows and Perring), on various ornamental andvegetable crops under greenhouse conditions. The development, survivorship, and fecundity of D.catalinae feeding on B. tabaci biotype B on collard plants were determined in the laboratory, andthe age-specific life table parameters were analyzed based on the life history data. Developmentaltime was 4.0,1.9,1.1,1.4,5.2, and 5.3 days for eggs, first, second, third, fourth instars, andpupae, respectively, with an average of 18.9 days from oviposition to adult emergence for bothsexes, 19.0 days for females, and 18.8 days for males. Adult longevities averaged 146.6 days forboth sexes, 122.6 days for females, and 170.5 days for males. After an average 4.9 dayspreoviposition period, females laid a mean of 5.6 eggs per day over a 97.0-day period. Netreproductive rate (R_0) and gross reproductive rate (Σm_x) were estimated by life table analysis at276.8 and 325.1, respectively. Generation time (T) and doubling time (DT) were 35.6 and 4.8 daysrespectively, and the intrinsic rate of natural population increase (r_m) was estimated at 0.158, orl= 1.171 for the finite rate of increase. The r_m value of D. catalinae is similar to or higherthan those of the whitefly feeding on most vegetable and ornamental crops, indicating that theladybeetle is capable of regulating populations of B. tabaci biotype B and other whiteflies undergreenhouse conditions.
