Although it is well known that Bacillus thuringiensis Cry toxins kill insect pest by disrupting midgut cells of susceptible larvae through their pore formation activity, it is not clear what intracellular events are triggered after pore formation on the cell membrane of the target cells. Here we analyzed the role of Cry toxins on autophagy activation using several cell lines as models as well as in Helicoverpa armigera larvae. The selected insect cell lines (Hi5, Sl-HP and Sf9) were susceptible to activated Cry1Ca toxin, but only Sl-HP cells were also susceptible to activated Cry1Ac toxin. In ...