نامه انجمن حشرهشناسی ایران (May 2014)
The two-sex life table and predation rate of Oenopia conglobata contaminata (Col.: Coccinellidae) feeding on pomegranate green aphid, Aphis punicae (Hem.: Aphididae), under laboratory conditions
Abstract
The ladybird species Oenopia conglobata contaminata (Menetries) is one of the major predators of pests in the orchards across Iran. The life history and predation rate of this predator were studied under laboratory conditions with 27.5 ± 2oC, 55 ± 5 RH and 16: 8 h (L: D) photoperiod to 6-cm petri dishes. To study the demography, a cohort containing about 100 eggs with less than 24h of age was chosen. Ladybeetle larvae were fed daily on the immature stages of pomegranate green aphids, Aphis punicae Pass. The daily fertility, immature developmental time, mortality and predation rate data were analyzed using age-stage, two-sex life table analysis - MSChart software. Means and standard errors of population growth parameters were calculated by bootstrap method. To determine the predation rate, the first-instar beetle larvae were fed on the third and forth developmental stages of A. punicae. The adult ladybirds were grouped in pairs of opposite sexes to investigate their predation rates on daily basis. The intrinsic rate of increase (rm), finite rate of increase(λ) , mean generation time (T0) and net reproductive rate )R0( were 0.181 d-1, 1.198 d-1, 30.58 d and 251.65 offspring per individual respectively. Predation rate of different stages of forth-instar larvae and both adult sexes were 49.56, 95 and 125, aphids respectively, and the average predation rate (C0) was 118 aphids that shows a high rate of predation on the aphid population.
