Mealworms are the larval state of many types of pests that invade pantries. Thriving on dry foods and sometimes in moist environments, mealworms can also appear in cabinets and from behind stoves and refrigerators.
White woolly worms look like little puffballs when resting on plants. Like other caterpillar species, they are voracious eaters. These little white woolly worms evolve into Virginia tiger moths.
The larval stage of any pantry pest may appear as worms in pet food. Dermestid beetles, in their caterpillar phase, are particularly fond of animal food, hair, and other household goods.