Morphological characteristics of the nymphal stages of the giant Asian mantis, Hierodula chinensis Werner (Mantodea: Mantidae), an alien species in Japan, with remarks on its identification

We identified an alien praying mantis found in Japan as the giant Asian mantis Hierodula chinensis by observing the characteristics of male genitalia. Nymphs hatched from oothecae collected in Nara Prefecture, Japan, were reared in a breeding room and compared with nymphs of the native Japanese species H. patellifera. Different from H. patellifera, the H. chinensis individuals passed through 5–7 nymphal instars before emerging as adults. The body color of the H. chinensis nymphs was brownish gray in the first instar, whereas the second and later instars were green. Unlike H. chinensis, H. patellifera had mottled patterns all over its body during the first to third instar. The first to third instar nymphs of H. chinensis had mottled patterns on the femurs of their forelegs, which is a diagnostic characteristic that no native praying mantis species has. From the fourth instar, 7–10 dorsal spines were observed on the foreleg coxa of H. chinensis, whereas only 3 or 4 spines were observed in H. patellifera. These findings show that H. chinensis and H. patellifera can be distinguished in all nymphal instars.