Tritrophic interactions of transgenic Bacillus thuringiensis corn, Anaphothrips obscurus (Thysanoptera : Thripidae), and the predator Orius majusculus (Heteroptera : Anthocoridae)

Laboratory feeding experiments using transgenic Bacillus thuringiensis vari ety kurstaki (Berliner) corn plants were carried out to study the effects o f B. thuringiensis-fed herbivorous prey on the predator Orius majusculus (R euter). Host plants were a transgenic B. thuringiensis-expressing (Cry1Ab) corn hybrid and the corresponding untransformed isogenic B. thuringiensis-f ree corn hybrid. The herbivorous prey species used in the experiment was An aphothrips obscurus (Muller), a thysanopteran pest of corn, not sensitive t o Cry1Ab toxin. The objectives were to quantify the effects of B. thuringie nsis-fed prey on the development and mortality of immature O. majusculus. T here was no significant difference in total mean mortality from hatch to ad ult eclosion between O. majusculus nymphs reared on B. thuringiensis-fed or B. thuringiensis-free prey. Similarly, no significant differences in total developmental time of O. majusculus was detected when reared on the two di fferent prey types. Overall mortality was low, confirming that the methodol ogy used was appropriate. We propose this approach as an efficient standard ized preregistrational testing for side effects of transgenic plants on sma ll predators such as Orius spp.