why the pitcher plant closes its lid as soon as an insect enters into the pitcher?

The pitcher plant closes its lid to trap insects as a means of protecting its digestive enzymes and maximizing nutrient absorption. This rapid closure helps prevent the insect from escaping, ensuring that the plant can digest its prey and absorb essential nutrients, particularly nitrogen, which is often scarce in its natural habitat. By efficiently trapping and digesting insects, the pitcher plant enhances its survival and growth in nutrient-poor environments.