I’ve compiled a picture of the egg cases of the mantis species in our area. The Carolina Mantis is our native species, and that’s the one that should be encouraged. The other two are the non-natives (the European and Chinese). I consulted an entomologist friend at OSU, and she is not opposed to destroying the Chinese or European mantis cases. She didn’t find much definitive research regarding whether or not the non-native species are out-competing our native one. While all three species are predators of plant pests, they are generalists as well and probably do prey on some beneficial insects and maybe the occasional hummingbird. The Chinese Mantis egg case is very recognizable due to its distinct shape. It might be difficult to differentiate between the other two however.
Click here for an excellent article on hummers and mantises.
-Naturalist Linda Gilbert