Zophobas atratus

Zophobas atratus,, the giant mealworm beetle, is a species of darkling beetle, whose larvae are known by the common name superworm, kingworm, barley worm, and morio worm. Superworms are common in the reptile pet industry as food, along with giant mealworms (Tenebrio molitor larvae treated with juvenile hormone).

The larvae resemble very large mealworms, about 50 to 60 mm (1.7–2.25 in) long when full size, but unlike mealworms, the ends of their bodies are very dark, almost black. Once they reach sufficient maturity, the larvae go stiff and still in a "C" shape to pupate. They emerge 1-3 weeks later with a white to light brown colour; eventually darkening to black. Pupation is commonly delayed by keeping larvae in high density with other larvae and plentiful food, and can be resumed by isolating larvae for 7–10 days. They will then pupate and, upon maturation, emerge as darkling beetles.

Zophobas atratus is generally accepted by captive lizards, turtles, frogs, salamanders, birds, koi and other insectivorous animals. Their nutritional values are similar to those of mealworms, so it is possible that supplementation with calcium is necessary if they are used as a staple food item. In some cases they are preferred over mealworms due to their softer exoskeleton, making them more digestible to some reptiles. The larvae are odor-free, but the adult beetles possess a pungent chemical defense that may be released when provoked. Zophobas atratus can easily be contained, making them ideal for breeding to feed a collection of captive insectivores. The nutritional profile of the larvae is "46.80% proteins, 43.64% lipids, 8.17% ashes and 1.39% carbohydrates."