*4.5.1 Yellow mealworm (*Tenebrio molitor *Linnaeus, 1758 Coleoptera: Tenebrionidae)*

*Distribution:* The yellow mealworm is the largest of the insect species that attack stored grain and grain products and is cosmopolitan in nature.

*Host range:* It mainly shows preference to the decaying grains, milled cereals, and usually the foodstuffs which are moist and are going out of conditions. It also feeds on the meal, grain, brand, bread, and dead insects.

*Bionomics:* Yellow mealworm or darkling beetle is a polished black or dark-brown beetle with finely punctured thorax and with longitudinally striated or grooved fore wings. Females lay about 300–500 eggs, which are bean-shaped, white, and sticky that adhere to food materials with one. Larvae are long, cylindrical, and initially white but later on changed into yellow color. Some larvae are not transformed into adults but instead that they continue their feeding and start molting and undergo hibernation during harsh conditions. Later on, some are transformed into pupae from where adults emerge in the form of beetles.

*Damage symptoms*: The presence of long, cylindrical, white larvae, usually attached to food materials is the main symptom of an infestation.
