Effect of different organic wastes on the life cycle of black soldier fly (Hermetia illucens)

Abstract

Black soldier fly larvae (BSFL) are known to utilize various organic wastes as their food for larvae growth and convert it into nutrient rich biomass. Due to their high protein composition, black soldier fly larvae are increasingly being used as animal protein source. However, little is known about how different organic substrate influence growth rate and nutritional composition of the larvae. This study therefore assessed the effect of different organic wastes on time interval between the insect life cycle stages, growth rate and how the substrate type influences nutritional composition of the black soldier fly (BSF) larvae meal. The study was laid out in a completely Randomized Design with four treatments each replicated six times. The four treatments included brewery waste, wheat bran, an assortment of market fruit waste and a combination of fruit waste and wheat bran. Different organic substrates each weighing 1.0 kg were replicated and placed in color coded buckets. The numbers of days taken to change from one stage to another was recorded. Growth rate including change in length and weight gain were measured as physical parameters of the larvae, pupa and the adults. The nutritional composition of the larvae meal produced from the different substrate was evaluated. Eggs incubated in wheat bran (WB) took the lowest number of days (5.3 days) to hatch into larvae while fruit waste took 7.0 days. Larvae incubated in brewery waste (BW) took the lowest number of days (38.5 days) to turn to pupa, adult and egg laying adults while larvae incubated in WB took the highest number of days (39.0 days) to turn to pupa, adult and eggs laying adults. BW had highest percentage of Crude protein with the mean of 52.8% while FW had the lowest with the mean of 34.26%. However, BW had the lowest percentage of total ash with the mean of 7.17% while WB had highest ash of 21.83%. FW had the longest length of larvae(1.2cm), pupa(1.6cm) and adult(1.3cm) while BW had lowest larvae length of 1.1cm and WB had the lowest pupa length(1.1cm) and adult length (1.1cm). FW had the highest weight of larvae (0.55g), pupa (0.76g) and adults (0.31g) while WB had the lowest weight of pupa (0.35g) and adults (0.30g).Therefore, type of organic wastes play a major role in the time interval BSF takes to change from one life stage to another, growth rate and the nutritional composition of the black soldier fly larvae.