I actually got one of my geckos to try these little things. She would eat whatever I offered her with tweezers, live or not, so I tried the flies. She took a few in her mouth, chomped em a little, and immediately shook her head and spit em all out. So apprently, they dont even taste good
BUT, mine did like the "Repti-Cricket" stuff, its by the same brand, comes in basically the same bottle but different label, and its just freeze dried crickets that seemed to be coated in this reddist stuff. They loved em. The thing with that is, they can be used as a treat only, since dead bugs dont offer much nutrition for the gecko, and who knows if they were even gutloaded before dying.