Functional Response of Chrysoperla Zastrowi Sillemi (Esben-Peterson) on Lipaphis erysimi (Keltenbach)

Abstract

Biological control of insect pests depends upon predating potential of natural enemies, which in turn relate to their functional response that is key to selection of a proper species for the biological control programs. The main aim of the study was to access the functional response of second instar grub of C. zastrowi sillemi (Neuroptera: Chrysopidae) on Raya (Brassica juncea) aphid Lipaphis erysimi (Keltenbach). Five different predator: prey densities of aphids (1:50, 1:100: 1:150, 1:200 and 1:250) were taken and results indicated the type-II functional curve response by logistic regression analysis of C. zastrowi sillemi on L. erysimi. Hollings Type II functional response signifies that the rate of prey consumption by a predator rises as prey density increases, but eventually remains constant in spite of increase in prey density. The aphids consumption, search rate (a`) and maximum predation rate (1/Th) was recorded less (7.36, 0.06 and 0.40) as compared (7.56, 0.068and 0.467) when grubs fed on artificial diet. However, time taken to handle a prey by second instar grub was more (2.55) on natural diet but less (2.17) on artificial diet.