Substrates: a solution to the mass production of African palm weevil (Rhynchophorus phoenicis) (F.) (Coleoptera: Curculionidae)

Rearing insect as food and feed has been identified as an emerging solution to improve global food security. Rhynchophorus phoenicis larvae are widely consumed in Ghana and Africa. However, the continuous production of the larvae is limited by the identification of available substrates and technology for mass production of the larvae. Substrates which include sliced false yam, spoilt garden eggs, spoilt onion, cocoa pod, elephant ear corm, peeled sugarcane, cocoyam cake, coconut coir, banana corm, oil palm yolk, and softer part of Raphia palm with each weighing 250 g were evaluated with R. phoenicis adults to assess the preferable substrates for egg-laying, hatching, and larval development. The results showed significant differences (P<0.005) on all the studied parameters of R. phoenicis reared on the different substrates. The parameters include pre-oviposition period, oviposition period, fecundity, number of eggs hatched, percentage hatchability, percentage larval survival, the average weight of larva, and percentage weight categories of 3-4 g, 4-5 g, and 5-6 g. There was a negative relationship between the number of male and female pairs and fecundity; the highest oviposition was achieved with one pair. Cocooning duration, percentage cocooning, and percentage adult eclosion were significantly different (P<0.005) among the substrates. Multiple regression analysis indicated that elephant ear corm, sliced false yam, and peeled sugarcane show a potential as alternative feed substrates for R. phoenicis larvae rearing.