Predation by Orius insidiosus1 on the Soybean Thrips, Sericothrips variabilis2 : Effect of Prey Stage and Density 3

Abstract
The predatory capabilities of nymphal and adult Orius insidiosus (Say) preying on larval and adult soybean thrips, Sericothrips variabilis (Beach), were assessed under laboratory conditions. Effects of varying densities of adult soybean thrips on predation by adult O. insidiosus were also determined. All stages of O. insidiosus tested were able to successfully capture 1st- and 2nd instar larvae and adult soybean thrips. The average number of soybean thrips killed per 24-h period increased with successive nymphal stages of O. insidiosus , and adult females killed more soybean thrips than did adult males. Adult male and female O. insidiosus exhibited a type-II functional response when exposed to varying densities of adult S. variabilis . Adult O. insidiosus appeared to feed past satiation at the high densities of soybean thrips.