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1
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
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Prey Density Dependent Life Table of Aphidoletes Aphidomyza Rondani (Dip., Cecidomyiidae) Feeding on Aphis Craccivora Koch (Hem., Aphididae) under Laboratory Conditions

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Madahi K., Sahragard A., Hossieni R.
Journal of Plant Protection Research
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2013
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tom 53
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nr 3
The life table provides an integrated and comprehensive description of development times, survivorship, and reproduction of a population. Life table parameters of aphidophagous midge, Aphidoletes aphidimyza Rondani (Dip., Cecidomyiidae) on different densities (5, 10, 20, 40, 60, 80) of third instar nymphs of Aphis craccivora Koch as prey, were studiedat (25±1°C, 70±5% relative humidity (RH) and a photoperiod of 16L : 8D h). There were no significant differences among the adult pre-ovipositional periods (APOP) at different prey densities. The total pre-ovipositional period (TPOP) of female A. aphidimyza was reduced significantly as prey density increased. The oviposition period was significantly different at varying prey densities. It was 4.333±0.211 and 5.625±0.324 days at the lowest and highest prey densities, respectively. Female longevity was also significantly different at varying prey densities. Fecundity was directly dependent on prey density (R2 = 0.990). The lowest fecundity was obtained at a density of 5 prey (52.5±1.544 eggs) and the highest was at a density of 80 prey, per day (121.375±4.301 eggs). The intrinsic rate of increase (r) was prey density dependent (R2 = 0.958), and ranged from 0.122±0.017 to 0.193±0.014 d-1 as prey density increased. The net reproductive rate (R0) was significantly increased as prey density increased. The peak reproductive values showed that female aphidophagous midges at the age of 15, 16, 17, 18, and 19 days made the highest contribution to the population at different prey densities. It was concluded that the increase in the densitits of third instar nymphs of A. craccivora had significant effects on demographic parameters of A. aphidimyza.
2
Artykuł dostępny w postaci pełnego tekstu - kliknij by otworzyć plik
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A laboratory and field condition comparison of life table parameters of Aphis gossypii Glover (Hemiptera: Aphididae)

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Hosseini-Tabesh B., Sahragard A., Karimi-Malati A.
Journal of Plant Protection Research
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2015
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tom 55
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nr 1
Life table studies are essential tools for understanding population dynamics. The life table parameters of Aphis gossypii Glover (Hemiptera: Aphididae) feeding on the host plant, Hibiscus syriacus L. were studied under laboratory (25±1°C and relative humidity of 65±5% and a photoperiod of 16L : 8D h) and field conditions (23–43°C, and relative humidity of 27–95%). The data were analysed using the age-stage, two-sex life table theory. The life table studies were started with 50 and 40 nymphs in laboratory and field conditions, respectively. Under laboratory conditions, A. gossypii reared on H. syriacus had a higher survival rate, fecundity, and longevity than those reared under field conditions. When reared under field conditions, A. gossypii had a longer nymphal developmental time, shorter adult longevity, and lower fecundity than those reared under laboratory conditions. The intrinsic rate of increase (r), net reproductive rate (R0), and the finite rate of increase (λ) under laboratory conditions, were higher than those obtained under field conditions. Nevertheless, there were no significant differences in the mean generation time T (days) between field and laboratory conditions. In the present study, the results clearly showed that life table parameters of A. gossypii were significantly different under field and laboratory conditions. These results could help us to understand the A. gossypii population dynamics under field conditions. The results could also help us make better management decisions for economically important crops.
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Functional and numerical responses of Scymnus syriacus marseul (Coleptera: Coccinellidae) to the black bean aphid, Aphis fabae Scopoli (Hemiptera: Aphididae) under laboratory conditions

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Sabaghi R., Sahragard A., Hosseini R.
Journal of Plant Protection Research
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2011
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tom 51
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nr 4
Functional and numerical responses are basic to any investigation of predator-prey relationships and key components in the selection of predators for biological control. In this study, functional and numerical responses of the female and male ladybeetles, Scymnus syriacus Marseul to different densities of third instar nymphs of Aphis fabae (i.e. 5, 10, 20, 30, 40, 60 and 80) as prey, were studied in a growth chamber (25°C, 65±5% RH and a photoperiod of 16L : 8D h) on the broad bean, Vicia fabae Linn. Using the logistic regression, a type II functional response for both female and male ladybeetles was determined. Using Nonlinear least-square regression, the searching efficiency (a') and handling times (Th) of the female and male adults were estimated as 0.123±0.006 h, 0.434±0.012 h and 0.115±0.008 h, 0.514±0.016, respectively. The Rogers model was used to estimate the maximum theoretical predations (T/Th) for female and male, which were 55.18 and 46.64, respectively. These results indicated a higher efficiency in female ladybeetles. The reproductive numerical response, in terms of eggs laid, increased curvlinearly with increasing prey density. The reproductive response trend was similar to the shape of the type II functional response. This similarity means both responses are interlinked and function simultaneously. The efficiency of the ingested food conversion (ECI) of the females decreased with prey density, as females laid 25±0.65 eggs when exposed to the highest prey density (80) and 3±0.44 eggs at lowest prey density (5).
4
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Resistance of canola cultivars affect life table parameters of Nysius cymoides (Spinola) (Hemiptera: Lygaeidae)

88%
Mollashahi M., Sahragard A., Mohaghegh-Neyshabouri J., Hosseini R., Sabouri H.
Journal of Plant Protection Research
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2016
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tom 56
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nr 1
A life table can be used as an important and appropriate tool to evaluate the susceptibility or resistance level of different host plant cultivars to insect pests. In the current study, we determined the suitability or inferiority of five different canola cultivars (Hayula420, Hayula401, Hayula50, Hayula60, RGS) to Nysius cymoides, under laboratory conditions. Data were analysed based on the age-stage, two-sex life table theory. Nysius cymoides which fed on Hayula420 had the longest nymphal period, while those which fed on Hayula50 had the shortest nymphal period. Developmental times (sum of incubation and nymphal periods) was longest for those which fe d on Hayula420 and the shortest for those which fed on Hayula50. The adult pre-oviposition period (APOP), total pre-oviposition period (TPOP), mean fecundity, and adult longevity of adults reared on different canola cultivars showed significant differences. The highest and lowest net reproductive rates (R0) were obtained for those which fed on Hayula420 (11.40 offspring per individual) and Hayula401 (5.47 offspring per individual), respectively. The highest value (0.0395 d–1) for the intrinsic rate of increase (r) was obtained for those which fed on Hayula 60 cultivar and the lowest value (0.0261 d–1) for those which fed on Hayula401 cultivar. The shortest and longest mean generation times (T) were obtained for those which fed on RGS and H401 cultivars, respectively. The lowest and highest values of life expectancy (exj) were obtained for those which fed on RGS and Hayula420 cultivars, respectively. The results showed that Hayula401 and RGS were not susceptible cultivars to N. cymoides. These cultivars showed higher resistance to N. cymoides, while Hayula60, Hayula420, and Hayula50 were found to be suitable cultivars but with lower resistance to N. cymoides, respectively.
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