Yellow mealworm

Mealworms (Tenebrio molitor) are the larvae of the yellow mealworm beetle, a black beetle with an average size of 1 to 2 cm. This insect belongs to the family of darkling beetles (Tenebrionidae) and is globally distributed.

Originally, this insect was considered a pest, as their natural feeding habits consist of consuming cereal products in dark storage areas. They also feed on vegetables, fruits and animal products. In the West, this insect has long been reared as feed for hobby animals, for example, reptiles and insect-eating birds. Meanwhile, their potential in food and feed applications also became known. This led to the approval of a Novel Food Dossier in the European Union (Regulation No. 2015/2283). Specifically, this means that dried and frozen mealworms as well as processed into meal may be sold as food on the European market.

The production phase (from egg to full-grown larva) takes on average 10 weeks. However, this depends on environmental conditions and feed (range 8 to 12 weeks). None of the life stages of this insect is dependent on light. The beetles have the ability to fly, but rarely do so. Consequently, they can be kept in open crates. However, keep in mind that the yellow mealworm is a cannibalistic insect: the mobile stages such as beetles and larvae can damage the immobile stages, i. e. pupae and eggs. For this reason, it is recommended to house the different life stages separately, in separate breeding crates. Typically, mealworms are reared on grain by-products (e.g. wheat bran) and a moisture source (e.g. carrots or other vegetables). Mealworms reared in conditions of 27 °C and 60% relative humidity using wheat bran and carrots as feed, can achieve below presented results.