Functional Response Of Chrysoperla Zastrowi Sillemi Reared On Meridic Diet And Natural Host Against Brevicorynae Brassicae

Abstract

Effective Bio-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 third instar grub of C. zastrowi sillemi (Neuroptera: Chrysopidae) on Raya (Brassica juncea) aphid Brevicorynae brassicae Linnaeus. Five different predator-prey densities of 1:50, 1:100, 1:150, 1:200, and 1:250 were used in the experiment, and the results revealed a type-II functional curve response through logistic regression analysis on B. brassicae. The type-II functional response envisage the rate of prey consumption by the predator increases with higher prey density, but eventually reaches a plateau despite further increases in prey density. The consumption of aphids, search rate (a`), and maximum predation rate (1/Th) by third instar grubs were observed to be lower (16.20, 0.16, and 0.47) fed on natural diet in comparison to grubs fed on an artificial diet were higher (16.54, 0.16, and 0.48). Nonetheless, the duration required by third instar grubs to handle prey was longer (2.11) on a natural diet but lesser (2.08) on an artificial diet.