This study highlights the complex relationship among the type of food, the performance of the locusts and midgut proteins as well as the impact of bacterial injection on the midgut proteins of adult. Grasshopper nymphs were supplied by different types of natural vegetation (grass, sorghum, sesban and clover) according to the seasons. The desert locust, Schistocerca gregaria Forskal fed on clover showed highest growth rate and largest mass and, vice versa in grass fed locusts. The insects fed on grass (low protein diet) recorded lowest midgut protein content while those fed on clover (high protein diet) recorded highest midgut protein. The change in diet produced protein profiles differences among the feeding groups of S. gregaria adults. Insects fed on clover had many characteristic bands in protein profile of midgut and vice versa in case of those fed on grass. After Bacillus thuringiensis israelensis (Bti) injection