Grasshoppers feeding on alpine buttercup

Do they have a guilty look about them? We walked up Avalanche Peak, in Arthurs Pass today, and after noticing a few flowers of Ranunculus lyalli that had been seriously chewed, I found these culprits. I did get a shot of the pair with the female chewing on one of the stamens, but this is probably the better photograph. The grasshopper is Sigaus australis, and the female is the larger, underneath the male.