Why do lepidoplerans die when they feed on Bt cotton plant? Explain how does it happen.

Explanation

Bt cotton plant contains inactive toxin protein. Once the insect ingests it, the inactive protoxins are converted into active form due to alkaline pH in the gut which solubilises the crystals. The activated toxins bind to the surface of the midgut, creates pores, causes swelling and lysis eventually leading to the death of the insect pest.