Life table of the aphid parasitoid Aphelinus asychls (Walker)(Hymenoptera, Aphelinidae) parasitizing different age groups of Aphis gossypii Glover (Homoptera, Aphididae)

摘要

The current laboratory study was designed to evaluate developmental duration, pupal mortality, sex ratio, longevity, fecundity and host feeding behaviour of the aphid parasitoid Aphelinus asychis (Walker) (Hymenoptera, Aphelinidae) parasitizing different age groups of Aphis gossypii Glover (Homoptera, Aphididae) at 25 + 1°C temperature, 60 + 10% RH and a photoperiod of 16:8 h (L:D). The results show that the development from egg to adult was significantly affected by host age. It was completed in 14.5 and 14.4 days in 1-2 day old A gossypii-nymphs, 13.5 and 13.1 days in 4-5 day old nymphs as well as 12.3 and 12.2 days with adults as host for females and males, respectively. No significant differences of pupal mortality and percentage of females among host age groups were detected. The mean percentage of mortality parasitizing different host age groups varied between 23.6 and 26.8%. The sex ratio (♂♂:♀♀) of A asychis with 1-2 day old A gossypii-nymphs as host was 1:0.9, with 4-5 day old nymphs