Local agricultural by-products for rearing superworm larvae (Zophobas morio): a Greek example

As the industrial insect production sector is rapidly growing, the high production cost of insects forms a constraint for the further growth of the insect industry. One of the main factors that greatly contributes to the total insect production cost and affects the profitability of insect farms is feed costs. Various agricultural by-products have been successfully evaluated and proposed as low-cost, alternative, insect feedstocks. In this context, this study evaluates a variety of Greek agricultural by-products as feeding substrates for Zophobas morio (F.) (Coleoptera: Tenebrionidae) larvae. More specifically, eleven agricultural by-products derived from the seed cleaning process of barley, oats, peas and vetch and the production of cotton, sugar beet and sunflower, were utilized singly and as components of compound isonitrogenous diets at two nitrogen levels (2.7% and 3.2% on dry matter basis). The results showed that larvae reared on sunflower meal, oat and barley (class II) by-products performed well in terms of larval growth and survival. In contrast, for most other diets tested high mortality rates were recorded, indicating the necessity for the formulation of diets that meet the nutritional requirements of the larvae. Our study highlights the potential of locally available by-products for the rearing of Z. morio larvae and contributes to determining their nutrient requirements.