If you go into a field you don't find one grasshopper you find none or thousand's! so for their habits I think that would be a yes.
I for now own grasshoppers and I have put tomatoes, leaves of all kinds, flowers, and a bunch of other stuff. It has all been eaten. So they eat all organic foods..
Grasshoppers don't eat other insect because they are herbivore (eat plants) not carnivore (eat meat).
grasshopper is a plant eating insect