Diet selection of three grasshopper species (Orth., Acrididae), in Spanish Pyrenees

The faeces content of grasshoppers (Stenobothrus stigmaticus, Omocestus haemorrhoidalis and S. nigromaculatus) living free-range in three vegetal communities was analysed by microhistological techniques. The grasshoppers' diet were compared with available vegetation and diet overlapping among three species was determined. Monocotyl plants constituted from 92%-100% of diet. Festuca gr. rubra was the species most selected by all grasshoppers in all areas we studied. Moreover, diet varies depending on plant communities. A high degree of diet overlapping was found. Importance of grasshoppes' diet in pasture dynamics is discussed.