There are plenty of different cricket species around in North America...I believe the cricket used as feeders now is actually from Europe originally..(I could be wrong...but too lazy to research it right now). Worse comes to worse, local cricket species could be used and farmed if the current species of crickets ends up getting wiped out here in North America.
Also, there are all kinds of other insects available on the market now to feed to animals we feed crickets to. Some are more expensive but most are just as good as feeders. Roaches, superworms, hornworms, silkworms, butterworms, phoenix worms are all good sources.
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PHLdyPayne