It is known widely as a pest insect of stored food grain products such as flour, and of poultry-rearing facilities and it is a vector of many kinds of animal pathogens.

They are tapering and segmented, with three pairs of legs toward the front end, and whitish when newly emerged from the egg and darken to a yellow-brown.

[2] A tropical species, the lesser mealworm thrives in warm, humid environments, both natural and established by humans.

[3] It easily colonizes agricultural establishments with abundant food sources and warm conditions, such as grain processing and storage facilities and poultry housing.

[2] The beetle consumes a wide variety of materials, including litter, bird droppings and bat guano, mold, feathers, eggs, and carrion.

[5] The larvae damage poultry housing structures when they search for suitable pupation spots, chewing through wood, fiberglass, and polystyrene insulation.

[6] Other insect residents of poultry housing include the housefly (Musca domestica) and its predator, Carcinops pumilio, a clown beetle.

[9] It transmits bacteria such as Campylobacter jejuni,[10] Salmonella enterica serovar Typhimurium, Escherichia coli, and Staphylococcus species.

[13] Poultry have difficulty digesting the beetle and larva, and if they eat them, they can experience intestinal obstruction and gut lesions.

[10] Like other darkling beetles, this species produces defensive benzoquinone compounds that can be irritating to humans, causing asthma, headaches, rhinitis, conjunctivitis, corneal ulcers, and dermatitis with erythema and papules.

[2] Before the beetle became problematic in poultry, it was better known as a pest of stored goods, including wheat, barley, rice, oatmeal, soybeans, cowpeas, peanuts, linseed, cottonseed, tobacco,[2] and dried meat.

[16][17][18] They have been reported as a good first food for Central American wood turtle (Rhinoclemmys pulcherrima mannii) hatchlings, because they are more active than common mealworms and their movement stimulates feeding behavior.

The larvae are either sold freeze-dried for consumption, or processed into food such as burger patties,[20] pasta,[21] or snack bars.

[23] On 4 July 2022, EFSA published an opinion confirming the safety of frozen and freeze-dried larvae of Alphitobius diaperinus for human consumption.

[24] Approval as novel food in the European Union followed on 6 January 2023 with the EU commission's publication of Implementing Regulation 2023/58 authorising the placing on the market of the frozen, paste, dried and powder forms of Alphitobius diaperinus larvae.