Enhancing Sustainable Production And Harvesting Of The Edible Grasshopper (Ruspolia Differens)

The global increase in food insecurity due to growing human population and rising demand for animal proteins presents an urgent need to explore alternative sources of proteins. Edible insects such as Ruspolia differens form a suitable alternative due to their high nutrient content. In addition, it has a high economic value that can supplement existing animal protein sources. However, its production has remained low due to seasonality and lack of mass rearing strategies. The grasshopper is collected from the wild using locally designed trapping techniques that are associated with major health and safety concerns. This study determined the optimal conditions for sustainable production and harvesting of R. differens. The study assessed effects of diets and cage designs on production of R. differens; efficacy of a novel trapping technology for mass harvesting of R. differens and influence of geographical location of collection on nutritional composition of the grasshopper. The study was conducted in Kenya and Uganda using a completely randomized design. Effect of diets and cage type on weight gain, development, growth rate, survival, cannibalism, reproductive performance, longevity, nutritional composition and quantities of R. differens was determined. All data were analysed using Analysis of variance (ANOVA) and Generalized Linear Model (GLM) using R statistical software. Diet type influenced development (P < 0.001), survival (P < 0.001), longevity (P = 0.015) and reproductive performance of R. differen. Faster development (57 ± 2.2 days), higher survival (87 ± 2.5%), longevity (88.9 ± 11.2) and fecundity (248 ± 20.3 eggs) occurred in R. differens reared on Diet 3 which was contained equal proportions of maize bran, wheat bran, dried Moringa oleifera leaves, lake shrimps and soybean meal. Cage type influenced weight gain (P = 0.022) and survival rate (P < 0.001); higher weight (0.43 ± 0.01g) and higher survival (63.3 ± 8.8 %) occurred in the wooden and netted cages respectively. However, it had no effects on development and growth rate of R. differens with better performance observed in wooden cage. The local trapping technology demonstrated a higher efficiency in mass trapping of R. differens (P = 0.002) and collected fewer non target invertebrate species (P = 0.014) compared to the novel collapsible trap. Proximate composition, fatty acid, amino acid, mineral, vitamin and flavonoid content of R. differens varied among collection sites. These findings demonstrated that Diet 3 can be optimized for domestication of R. differens, the diet substrates and affordable and can be easily accessed by farmers. The wooden cage showed better growth and development of R. differens, however, it requires further improvement to enhance survival of the grasshopper. The novel trapping technology can be modified to enhance mass harvesting of R. differens. Rusplia differens should be used to complement existing protein sources, improve health nutritional outcomes and livelihoods especially in sub-Saharan Africa where food insecurity and malnutrition remain a challenge to socio-economic development.