مطالعه نرخ امید به زندگی و زنده مانی کفشدوزک شکارگر Exochomus nigripennis (Erichson) با تغذیه از شته جالیز Aphis gossypii (Glover)

Aphis gossypii Glover (Hemi.: Aphididae) is a polyphagous aphid distributed nearly world-wide, known as a vector of many viruses, and is an important pest of cucumber. The ladybird, Exochomus nigripennis (Erichson) (Col.: Coccinellidae) is a polyphagous predator, commonly found in horticultural and forestry systems of Iran. This predator is an aphidophagous that can feed and reproduce on A. gossypii. We studied the life expectancy and survival of E. nigripennis fed on 2nd and 3rd instar nymphs of A. gossypii at 25 ℃, 60% RH, and a photo period of 16:8 h (light:dark) on cucumber leaves. A cohort of 80 eggs was used. The mated females were transferred to 80 new experimental units, and after 24h the females and extra eggs were removed and only one egg was reared in each unit. To determine the life expectancy and the survival of E. nigripennis, eggs were inspected under a stereomicroscope daily. Results showed the probability that a newborn egg of E. nigripennis reared on A. gossypii survived to the adult stage was 0.488 for females and 0.350 for males. The life expectancy of E. nigripennis at the first day of life was 64.83 days and decreased by increasing age. It was higher for the females compared to that of males, and at the beginning of adult emergence was 54.49 and 31.57 days for females and males, respectively. As increasing age from egg stage to adult, the reproductive value increased, and then slightly decreased. The reproductive value (Vxj) of the female reached a peak on the 45th day (147.22 d-1). The results of this research can be useful in the field of biological control of A. gossypii.