Evaluating the ability of desert locusts (Schistocerca gregaria) to grow when feeding on tomato leaves (Solanum lycopersicum) versus wheatgrass (Triticum aestivum)

Abstract

The desert locust (Schistocerca gregaria) is a notorious swarm-forming agricultural pest widely collected for its use as food and feed. Its ability to grow on tomato leaf waste as a sole nutritional source was investigated given its ability to consume a wide range of plants. The growth and nutrient composition of desert locusts and their generated frass were compared in nymphs reared on tomato leaves versus wheatgrass. The desert locusts demonstrated higher growth on wheatgrass diet, but they also thrived on tomato leaves without observed mortalities. An average production of 14.38 g desert locust biomass consumed 375.8 g of fresh tomato leaves. Desert locusts fed with tomato leaves had higher crude protein content (61% compared to 58% in wheatgrass-fed desert locusts) and lower fat content (8% compared to 14% in wheatgrass-fed desert locusts). The diet also influenced the levels of Ca, Cu, Mn, S, and Zn in the desert locust biomass. Furthermore, the analysis of the generated frass revealed significant differences in the levels of B, Ca, Cu, K, Mg, Mo, Na, P, S, Zn, and N, depending on the plant material provided. The findings suggest that the desert locust can be reared efficiently on tomato leaves, transforming this waste stream into a protein-rich insect biomass and frass.