The present invention relates to the field of insect pests control, using methods and compositions which comprise of alpha-amylase analogous mutant inhibitors (αAIs). More specifically, the invention provides new αAIs analogous mutant molecules for controlling insect pests, in particular boll weevils (Anthonomus grandis), partially or totally presenting reduction of the amylolytic activity of the digestive enzymes in the intestinal lumen of the insect. Other aspects of the invention include gene constructs containing the nucleic acid molecules that code for the alpha-amylase inhibitors, heterologous expression methods of the new molecules in the active form, and the use of these molecules for controlling insect pests. The invention also provides analogous synthetic genes optimized for their transformation and expression in plants.