Food and nutritional skills of the edible caterpillar Cirina butyrospermi vuillet (Lepidoptera: Attacidae) on non-ordinary diets for industrial breeding

Abstract

The shea caterpillar C. butyrospermi has exceptional nutritional features. This insect is however univoltine, specific to shea and its larvae are mature only in July and August. Their food capacity apart from shea is poorly documented to suggest mass production and dietary diversification. This study aimed at evaluating the feeding and nutritional abilities of the caterpillar on non-ordinary natural diets. The approach consisted of feeding 21-day-old larvae with diets of choice or by imposition and then measuring some biological parameters of the edible insect. Nine diets including a control (shea leaves) were used in eight repetitions to the larvae in order to evaluate their preference index using the Chesson formula. Nutritional abilities were assessed for 12 days in a Fischer design with seven treatments (seven diets) randomized in four repetitions. Each treatment contained a single diet and one solitary or three gregarious larvae. The trace elements of the diets were measured by Inductively Coupled Spectrometry (ICP-AES). Caterpillars feed day and night and it does not matter whether they are gregarious or solitary. They preferentially feed on diets D1 (ƛ: 0.931) and D3 (ƛ: 0.791). Food rations were significantly higher in the control (989.86 mg/day), D3 diets (931.92 mg/day) and D1 (478.00 mg/day). Only the control and the D1 diet presented respective positive FCRs of 20.54% and 31.94% and respective positive AWGs of 53.63 mg/larva and 23.38 mg/larva. The pupation rate was 57.23% with the Control and 6.97% with the D1 diet. These two diets had similar levels of trace elements and macronutrients. The D1 diet could be used for mass breeding and contribute to the dietary diversification of the caterpillar