Abstract: Predation behavior is widely utilized to evaluate the potential of a predator in biological pest control. The common approaches using mathematic modeling or direct observation in microcosms without plants often lead to either over or under-estimation of the potential. This study aimed at estimating behavioral parameters of predation on different instar larvae of Spodoptera litura by the predatory stinkbug Arma chinensis across nymphal instars in laboratory experiments using potted plants. Different instars of S. litura larvae (L1, L2, L3 and L4) were individually subjected to predation by variable instars of individual A. chinensisnymphs (2nd, 3rd, 4th and 5th instar) on potted soybean (Glycine max). Predation behavior during two hours was recorded and analyzed to detect the trend across predator’s instars in response to variable instar caterpillars. Preyhandling time decreased in a quadratic pattern across stinkbug nymphal stages when encountering L1, L2 or L4 prey, and in a cubic pattern when encountering the L3 prey. Prey consumption increased linearly with the increase of stinkbug nymphal instar for the L2, L3 or L4 prey, and showed an “archshaped” curve for the L1 prey. Predation success increased linearly with the increase of stinkbug instar for the L2 prey, and had no correlation with it for the L1, L3 or L4 prey. The number of stylet stinging did not change with stinkbug instar. Our findings suggest that the evaluation of predation of S. litura by A. chinensis should take into account of the age of both prey and predator.

Key words: photosynthetic efficiency, fruit crop intercropping, diurnal variation., leaves in ear position, water and fertilizer regulating