Hippodamia tredecimpunctata Goel. is a coccinellid predator on certain economic pests infesting some plants in Egypt. The developmental period, feeding capacity of its larval instal's and adults, adult longevity, fecundity and the functional response of the adult were estimated under laboratory conditions. Adults and larvae of the predator were provided with the wheat aphids, Schizaphis graminium Rond. as preys. Results indicated that, the average incubation period of the eggs was 4.4±0.22 days at 21.5±0,35°C and 63-68%RH. At the same conditions, the durations of larval and pupal stages were 1 6.47±0. 17 and 8.60±0.19 days, respectively, while the adult longevity was 61.25±6.60 days for males and 52.88±6.77 days for females.Under the same laboratory conditions and by feeding on aphids, first eggs were laid after a pre-oviposition period of 13.5±1.70 days and the female deposited a total of 306.2±38.66 eggs throughout an oviposition period of 40.38±3.27 days. After the oviposition period has ceased, the female spent a post- oviposition period of 8.5±1.10 days until mortality. Data showed that the consumption rate of S. graminium by H. tredecimpunctata has increased as the larval instal' grew older. The highest consumption rate, (121.07±3.74 aphid individuals) was recorded from the predator's 4th instal' larva. Daily rate of aphid consumption by the adult beetle was 32.63±1.02 for male and 34.24±0.32 individuals for female at 22.5±0.25°C and 58 - 70% RH. Results of functional-response experiment showed that adult stage exhibited Holling's type II functional response. |
