Host fitness of different aphid species for Diaeretiella rapae (M’Intosh): a life table approach

Diaeretiella rapae [M’Intosh (Hymenoptera: Braconidae)] is a koinobiont, cosmopolitan, solitary and polyphagous endo-parasitoid of various species of aphids especially attacking on cruciferous plants. Present study intended to assess the quality of three aphid species i.e. Myzus persicae (Sulzer), Lipaphis erysimi (Kaltenbach), and Brevicoryne brassicae (Linn.) (Hemiptera: Aphididae) as host influencing the survival rate, demography, population growth, longevity and sex ratio of D. rapae. Diaeretiella rapae exhibited considerably highest life expectancy on M. persicae followed by L. erysimi and B. brassicae. However, mortality survival ratio and indispensable mortality was highest at pupal stage when D. rapae was reared on M. persicae. Moreover, natality rate (mx), potential fecundity (pf), net reproductive rate (R0) and intrinsic rate of increase (rm) was significantly (P < 0.05) highest on M. persicae followed by L. erysimi and B. brassicae. Similarly, adult longevity was prolonged on M. persicae with female biased sex ratio. Based on the present study it can be concluded that M. persicae proved to be the best host for D. rapae, however, L. erysimi and B. brassicae proved to be the moderate or less suitable host for the multiplication of this parasitoid species. Moreover, it may be difficult to find whether the use of a particular food for nutrition by a host of parasitoid will have a positive or negative impact on biological performance of parasitoid, therefore, there is an urge to determine these facts experimentally using biochemical analysis.