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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

Madahi, Khadijeh, Sahragard, Ahad, Hossieni, Reza
Journal of plant protection research 2013 v.53 no.3 pp. 253
Aphidoletes aphidimyza, Aphis craccivora, adults, aphidophagous predators, eggs, fecundity, females, instars, life tables, longevity, midges, nymphs, oviposition, photoperiod, relative humidity, survival rate
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