Has anyone ever fed those "tent worms" that are all too common in the North-east? They are those fuzzy things that ang out in packs on trees and eat the leaves.
It is not widly recomended to feed foods from "wild" sources as you can not control what the feeders ingest. Pesticides are of major concern.
Also, parasitic loads are likely to be higher in free range feeders.
I don't know if they would be safe for a leo even if there weren't these concerns.
When I bred Praying mantises I tried feeding them tent's and they ended up spinning tents all inside the mantis tanks, which ended up restricting the mantises to tiny little spaces in the tank. One even died because It got tangled up in the silk that the tents were spinning their tent with. And the mantises that didnt die wouldnt even touch them. They wanted less fuzzy prey I suppose.
For leos, I would say no. You dont know what toxic substances they have been exposed to, both from insecticides and from eating plants that might be poisonous to leos. Plus I doubt that the leos would like eating something so hairy. And from my mantis experience, im pretty sure that the tent's would just start spinning silk tents inside your gecko tanks.