Effects of prey's host plant species on biological efficiency of predator ladybird, Hippodamia variegata (Goeze) (Coleoptera: Coccinellidae)

The aphidophagous ladybird, Hippodamia variegata (Goeze), is an effective predator in most agricultural ecosystems. The host plant species of aphids could be an effective factor on life history characteristics and efficiency of their predators. Therefore, the effect of six host plant species of cabbage aphid, Brevicoryne brassicae (Linnaeus) including cabbage, cauliflower, radish, turnip, canola and ornamental kale on development, reproduction, fecundity and life table parameters of H. variegata were studied in this research. The results showed that the suitability of aphids from various six host plants species differed for the development and reproduction of H. variegata. The total developmental time (from egg to adult emergence) was shortest (14.69 days) when reared on aphids on canola. Total fecundity rates significantly differed among tested host plants and the highest rate was observed on canola (646.44 eggs). The net reproductive rates (R0) of ladybird varied from 252.78 female offspring / female / generation on ornamental kale to 116.74 female offspring / female / generation on cabbage. Intrinsic rate of increase (rm) as an important index of suitability of prey host plant species on the population increase of ladybird beetle, varied from 0.155 day-1 on cabbage to 0.188 day-1 on canola. Based on the intrinsic rate of increase, the suitability of tested host plants in decreasing order was: canola, cauliflower, ornamental kale, radish, turnip and cabbage. Our finding may provide basic information for better understanding of the tritrophic interactions of the plant-aphid-predator relationships and also mass production of H. variegata.