Evaluation of alternative substrates for rearing the yellow mealworm Tenebrio molitor (L)

Abstract

Larvae of the mealworm beetle Tenebrio molitor is commonly used as feed for pets and food for humans due to its rich nutrient contents. The beetle breeds prolifically and are reared in close proximity with their diet; known as substrates. However, the most commonly used substrate, wheat bran, is expensive making the rearing out of reach to many, especially in developing countries. This study evaluated the suitability of six other potential substrates; wheat flour, maize flour, Lucerne pellets, dog food, soya four and oats in comparison to wheat bran in order to explore a cost-effective alternative rearing substrate for mealworms. To achieve this, the mealworms were reared in a climate-controlled chamber and the total numbers, weight and the fecundity were determined for each substrate. Wheat bran and wheat flour produced the most mealworms, had the highest fecundity with wheat bran, Lucerne pellets an oat producing heavier worms than all other substrates. Maize flour, wheat flour and Lucerne, were found to be the most cost-effective alternative substrates for rearing mealworms with the cost per gram at 0.07, 0.05 and 0.04 US$ respectively. Both wheat flour and maize flour are easily accessible, have a long self-life thus ideal for both large-and small-scale production.