Do you ever find it a problem that the scarabs can't eat anything?
But they can. All alone they only are 2/1 So yea, they can't eat anything then, but add a second Scarab and both become 2/2, thus you can eat ?/1 critters. And of course each time you eat something that scarab will get +1/+1.
Recap: Yes, scarabs can eat things. Scarabs Health/deffence is based off the number of scarabs on the feild +/- their indevidual bonus. They gain +1/+1 each time they go 'om nom nom'