Grasshoppers are subjected to attack by a wide range of predators and parasites at all stages of their life cycle. Fecundity of these predators and parasites of the insects was affected when grasshoppers were contaminated with Mermis spp. Mostly, the females laid fewer eggs than normal. The numbers of eggs produced were 17.5±3.0, 11.2±5.3 and 8.6±4.3 for Poekilocerus pictus, Oxya velox and O. hylahyla, respectively, for infested insects, whereas, it was 43.3±5.2, 37.8±6.30 and 39.34±5.2 in uninfected grasshoppers. Beside this, it was also noticed that insect infected with Mermis spp. did not survive for long. Dissection examination showed that there was significant suppression of oocytes and testis development in infected individuals.