I don't know what they could be. Just bugs. Are you sure it's them that's doing the eating? If you wanna spray 'em organically, try a chilli and/or garlic spray. Chemically,hit 'em with some pyrethrum and a dash of whiteoil. A bit of potassium as a liquid fertiliser might help ward off future attcks. Healthy plants are not inviting to most insects and potassium helps build cell walls and toughens leaves up. Also, you could try covering them with a mosquito net but you'll have to get rid of the existing bugs first. I use this method on some veges and it works very well. As long as you don't need insects to pollinate that is:)