On the species status of Blattella germanica and Blattella asahinai (Blattodea, Blattellidae), and other morphologically similar species

Blattella germanica (Linnaeus, 1767), a member of the Blattellidae family within the order Blattodea, is a significant global sanitary pest. Several species within the genus Blattella Caudell, 1903 and its closely related genera (Episymploce Bey-Bienko, 1950; Symploce Hebard, 1916; and Jacobsonina Hebard, 1929) exhibit external morphological traits similar to those of B. germanica. By integrating morphological identification and molecular analyses, one new species was identified: Jacobsonina uncata Cai, Yao & Che, sp. nov.

Additionally, Blattella asahinai Mizukubo, 1981 was downgraded to a subspecies of B. germanica. The application of molecular data, specifically cytochrome oxidase c subunit I (COI), has proven to be a straightforward and effective method for distinguishing B. germanica from its morphologically similar relatives.