Comparison of Life Tables of Cheilomenes sexmaculata (Coleoptera: Coccinellidae) Under Laboratory and Greenhouse Conditions.

Abstract

The ladybird Cheilomenes sexmaculata (F.) is an important aphidophagous predator in Asia. In order to mass rear predators for biological control, it is valuable to identify the features of populations that are affected by variations in field conditions. Life tables can provide comprehensive descriptions of the development, survival, and fecundity of a population. However, there are few life table studies of C. sexmaculata. Studies of life history have been carried out in many arthropods using the traditional female age-specific life table, which takes only female individuals into consideration, while the variations in developmental rates amongst individuals are ignored. In this paper, we constructed life tables for C. sexmaculata fed on Myzus persicae (Sulzer) both at constant temperature in the laboratory and fluctuating temperature in the greenhouse, and analyzed the data using the age-stage, two-sex life table. The bootstrap technique was used to estimate the standard errors of the population parameters. The results showed that preadult C. sexmaculata developed more slowly and had lower survival and reproductive rates under greenhouse conditions, as indicated by the curves of age-stage survival rate (s(xj)), age-stage-specific fecundity (f(x j)) of the female stage, age-specific fecundity (m(x)), and age-specific maternity (l(x)m(x)). Our results also showed that the intrinsic rate of increase (r), net reproductive rate (R(0)), and finite rate of increase (λ) under laboratory and greenhouse conditions were 0.1668 d(-1) and 0.1027 d(-1), 192.1 and 53.0, and 1.1815 d(-1) and 1.1082 d(-1), respectively. Our results revealed significantly different life table parameters for C. sexmaculata under laboratory and greenhouse conditions. This information will be useful for developing a successful mass-rearing program for C. sexmaculata for use in biological control.