Effect of Substrate Moisture on the Growth Performance and Survivability of the Black Soldier Fly (Hermetia illucens L.) Larva

The production and supply of animal protein are dropping with the increasing world population, especially in developing countries like Nigeria. Some alternatives such as several edible insects are challenged by people’s unwillingness to engage in entomophagy. Therefore, the need to improve animal protein production and supply has necessitated measures that can curb the major issue in this sector, which is the high feed cost occasioned by the scarce and expensive fishmeal used as the animal protein source in feeds. Black soldier fly which feeds on low-cost organic wastes can bridge the gap between entomophagy and animal protein supply as an indirect source of animal protein by substituting the expensive fishmeal in animal feed. However, though the larva of the black soldier flies can thrive in almost all organic substrates, it has its moisture requirement for survival, growth and development. In this research poultry droppings were used at three different moisture levels of 30%, 50% and 70% to rear the larva. The larvae reared at 70% moisture level had the best growth performance in terms of length, weight and width gain, although the length increase did not vary significantly between the larvae reared at 50% moisture and those reared at 70% moisture level. The lowest performance for all growth parameters examined was observed from larvae reared at 30% moisture level. The survival rate for larvae reared at 50% and 70% moisture levels did not vary significantly but were both significantly higher than that of those reared at 30% moisture level. The results showed that the larvae black soldier flies thrive better at substrate moisture levels above 50%.