Effects of adult nutrition were investigated by measuring female longevity, body weight, fertility and ovariol yield in the grasshopper, Euprepocnemis plorans reared on 3 different host plants. Rearing the insect on lupine (Lupinus termis) and horsebean (Vicia faba) caused significant reduction in fertility and ovariol yield of its first and second pods compared with those reared on clover (Trifolium alexandrinum). Resorption bodies were significantly higher in the ovariols of females fed on L. termis and V.faba. Diet also affected longevity and body weight. Fecundity was highest in females reared on T. alexandrinum. Significant reduction in haemolymph protein was noted in females reared on L. termis and V. faba. Nitrile (allylcyanide) significantly reduced the approximate digestibility (AD), efficiency of conversion of ingested food (ECI) and efficiency of conversion of digested food (ECD), inhibited nymphal growth, increased food consumption and decreased its assimilation. Feeding grasshoppers on T. alexandrinum treated with 125–250 μ mole/g resulted in various degrees of malformation and death.