Rearing of Rhynchophorus phoenicis Fabricius (Coleoptera: Dryophtoridae) last instar larvae on three artificial substrates in Kisangani, Democratic Republic of the Congo

Abstract

Insects have been a particularly popular resource for human and animal nutrition since the turn of the century, owing mostly to population increase and the ever-increasing need for animal protein. A five (5) months experimental study was carried out at the Yangambi Laboratory of Applied and Functional Entomology in Kisangani to explore a variety of artificial substrates for the mass production of African palm weevil (Rhynchophorus phoenicis) larvae. The larvae were reared in plastic boxes with three types of substrate: T1, based on ripe plantains; T2, based on brewery flour; and T3, based on Makololo flour, which was used as the energy component and made up 60% of the substrate. Palm oilcake and soybean, which accounted for 40% of the substrate, supplied protein. Each treatment was divided into two (2) groups (A and B), this subdivision being based on the presence or absence of soybean meal. 0.8 kg of substrate for each box was given ad libitum every two weeks (14 days). The adults used were captured after trapping in the forest. Broodstocks were randomly assigned to 42 groups (boxes), randomly assigned to six (6) feeding treatments, using a completely randomised design (CRD) with seven (7) replicates. After feeding trial, the results showed that the number and weight of last instar larvae differed between treatments. From the various treatments, an average of 398 last instar larvae LIV, rearing for 32 to 37 days and weighing between 1.56 and 2.22 g were collected. The substrate based on ripe plantain (T1A) produced the highest average number of larvae compared to others (p<0.05), while the substrate based on brew (T2B) produced LIV with higher average weights (p<0.05).