Impact of two bisacylhydrazines on development of Ephestia kuehniella Zeller, 1879 (Lepidoptera: Pyralidae) with respect to cuticular thickness and protein

Abstract

Prototype (RH-5849) and Tebufenozide (RH-5992), two insecticides that imitate the action of ecdysone. Our study was conducted to assess the adverse effects of two different doses of these compounds; (LD50 and LD90, RH-5849: 0.05 μg/insect; 0.18 μg/insect and RH-5992: 0.005 μg/insect; 0.05 μg/insect) were applied topically on newly ecdysed pupae. Cuticular thickness during metamorphosis and the quality of cuticular protein at apolysis were measured. Results had been shown that both analogues increased old cuticle thickness (pupal cuticle) in the first days, then they reduced it. Likewise, the RH-5992 induced the precocious apolysis and the early secretion of new cuticle (adult cuticle) and increased it at the fifth, seventh and ninth day. On another hand, the electrophoresis separation of cuticular proteins was shown that the RH-5849 provoked the absence of one protein band while the RH-5992 induced the absence of two protein bands. Thus, ecdysteroid agonists were found to interfere with cuticule secretion in E. kuehniella confirming the primary mode of action of the bisacylhydrazines insecticides.