Courtship songs of Chrysoperla nipponensis (Neuroptera: Chrysopidae) delineate two distinct biological species in eastern Asia

The substrate-borne vibrational courtship songs of type A and type B Chrysoperla nipponensis (Okamoto) (Neuroptera: Chrysopidae) are described in detail, from populations sampled throughout Japan and near Beijing, China. The song of type A is long (≈ 5-6 s) and is made up of numerous (four to 12) volleys of four distinct forms that differ in their carrier frequencies. The song of type B is shorter (≈2 s) and functions as a repeated single-volley song, but each volley is shown here to consist of four to six distinct subsections. During heterosexual duets, partners of type A exchange their long multi-volley songs, whereas partners of type B repeatedly exchange short single-volley songs. Geographical variation within each song type is low and largely insignificant. In addition, previously recognized mitochondrial (cytochrome oxidase subunit I) haplotypes Al and A2 of type A C. nipponensis do not have different songs. These results support the hypothesis that types A and B C. nipponensis are distinct species, with type A corresponding to the nominate species (i.e., C. nipponensis s. str.) and type B as yet unnamed. Their songs are among the most complex yet found in the Chrysoperla carnea swarm of cryptic species.