Life table parameters of Chilocorus bipustulatus (L.) (Coleoptera: Coccinellidae) on two different prey [Aspidiotus nerii (Bouche), Hemiptera: Diaspididae] densities

Abstract: In this research, the life table of Chilocorus bipustulatus was investigated on two different prey densities. Aspidiotus nerii was used as prey and two groups of the predator were fed daily 320 and 640 prey, beginning from the first instar till the death of the last individual. Durations of larval and pupal stages and egg numbers of adults per day were determined. Trials were performed in a climatic chamber with 26 ± 1 °C temperature and 65 ± 1% RH. As a result of the experiments, net reproductive rates of C. bipustulatus individuals fed with 320 and 640 prey were 13.827 and 35.554 females/female, while intrinsic rates of increase were 0.066 and 0.100 females/female/day, and mean generation times were 40.022 and 35.669 days, respectively. Best survival rates of each experimental group were calculated according to Weibull distribution and best survival fits were found for both groups. Parameters of best survival rates were determined as b = 3.97, c = 0.62 for the group fed on 320 prey and b = 8.13, c = 0.94 for the group fed on 640 prey. According to these results both groups have Holling’s type III survivorship curves. Fecundity of C. bipustulatus was determined with Enkegaard equation. Best-fit parameters of fecundity were calculated as a = 1.34, b = 0.16; and a = 1.95, b = 0.21 for 320 and 640 prey groups, respectively.