Rhynchophorus phoenicis production: A comparative study of different rearing protocols

Abstract

The traditional methods of sourcing and semi-domesticating the African palm weevil Rhynchophorus phoenicis Fabricius (Coleoptera: Curculionidae) larvae persist among the inhabitants of Ghana. However, these methods produce only a small proportion of the market demand for the larvae in Ghana. A containerized system of producing larvae has been found to facilitate production for socioeconomic purposes, thereby enhancing the sustainable utilization of the larvae all year round. We evaluated the life history parameters of R. phoenicis on three different rearing protocols that used different agricultural by-products, container types, and number of adult pairs for production. The different protocols were laid out using the Completely Randomized Design (CRD) with 10 replications. The fecundity of the adults differed significantly among the protocols. The highest fecundity was recorded on Protocol 2 (145.50 ± 16.55), followed by control (98.50 ± 12.05), Protocol 3 (84.50 ± 9.50), and Protocol 1 (45.00 ± 11.58). Protocol 2 recorded the highest larval survival rate, followed by Protocols 1, control, and 3. Among the rearing protocols, the highest intrinsic rate of natural increase (rm) (days) and net reproductive rate (Ro) were observed in Protocol 2. The lowest mean generational time (T) was recorded on Protocol 2 (76 days) while the highest (92 days) was recorded on Protocol 3. Our findings showed that Protocol 2 supports fecundity, larval development, cocooning formation, and adult emergence. The adoption of Protocol 2 by smallholder insect farmers can contribute to the development of future commercial rearing systems for R. phoenicis larvae.