Evaluation of Food Consumption, Haemolymph Protein Content and Survival of the Grasshopper Euprepocnemis plorans Fed on Clover, Lupine or Horsebean

Abstract

The effects of diet on quantitative nutritional indices were measured in fifth-instar female nymphs of the grasshopper, Euprepocnemis plorans. Analysis of the main and interactive effects of feeding on the host plants lupine (Lupinus termis), horsebean (Vicia faba) or clover (Trifolium alexandrinum) and some of the plants’ allelochemicals indicated that nymph performance was adversely affected by the hydrogen cyanide (HCN) and quinolizidine in horsebean and lupine respectively. Assimilation of clover was higher than of lupine or horsebean. Relative growth rate (RGR) was significantly higher in grasshoppers fed on clover than in those fed on either lupine or horsebean. Relative consumption rate (RCR) was in the order lupine > clover > horsebean. The efficiency of the digested and ingested food conversion were significantly lower in grasshoppers fed on lupine or horsebean than those fed on clover. The duration of the fifth instar was in the order horsebean > lupine > clover. Grasshoppers fed on horsebean or lupine lost weight during the experiment, with a greater weight loss recorded in those fed on horsebean. Grasshoppers contained the highest concentration of haemolymph proteins when fed on clover. Short-term feeding on lupine and horsebean resulted in 10 and 20 % mortality respectively, and nymphs that died on a horsebean diet were malformed.