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

Explanation

Some strains of Bacillus thuringiensis produce protien that kill certain insects each as lepidopterons (tobacco budworms, armyworm, bettles and flies). B. thuringiensis forms protein crystals during a particular phase of their growth. These crystals contain a toxin insecticidal protein. The activated toxin binds to the surface of midget epithelial cells and create pores that causes cell swelling and lysis. The toxin is coded by a gene named cry.