My house has an earwig problem this year, so I put one in with one of my baddest L3s, who wanted nothing to do with it. I put it in with another of my baddest L3s, who also seems mostly uninterested. In both cases, the mantis got close and looked ready to strike, but then backed off. To me, they look like they could defeat an earwig - they've taken down moths that were much bigger. I hope they'll eat earwigs once they molt to L4, because the earwigs are abundant, annoying, and free.