Solitary, but on quite a number of my hostas. I am wondering recently whether some of the hosta leaf damage is caused by other insects like this, not only the slugs. I thought I should start with a positive ID first. Thank you so much for your time! Eastern Ontario
Your photos are of a spittle bug. The young are usually found in a mound of what looks like spit. Once they are grown then they don’t need the spit for protection and are out hopping about. They do feed on plants with sucking mouthparts. So, they are probably not the cause of damage on hosta.
Large numbers of nymphs can cause stress to a plant and stunt of growth. Adults do not cause economic damage.