Comparison of the activity of ecdysone agonists in Bombyx mori and Spodoptera littoralis by in vitro reporter assays and in vivo toxicity assays

Abstract

Ecdysone agonists such as dibenzoylhydrazines have been successfully used in biological control programs of lepidopteran and coleopteran pests. However, little information exists with respect of the specificity of the action of such compounds towards different species of Lepidoptera or Coleoptera. In this study, we compare the activity of ecdysone agonists belonging to three different chemical classes (dibenzoylhydrazines, acylaminoketones and tetrahydroquinolines) between the lepidopteran pest Spodoptera littoralis and a beneficial lepidopteran species, the silkworm Bombyx mori. The activity of ecdysteroid agonists is measured both in vitro, using an ecdysone-responsive reporter assay based on transfected or transformed Spodoptera- or Bombyx-derived cell lines (Sl2 and Bm5 cells, respectively), and in vivo, by toxicity tests on Spodoptera and Bombyx larvae. The study aims at the elucidation of the species-specific factors that determine the activity of ecdysone agonists against Lepidoptera.