Songs and morphology in three species of the Chorthippusbiguttulus group (Orthoptera, Acrididae, Gomphocerinae) in Russia and adjacent countries

Songs and morphology are compared between Chorthippusmiramae (Vorontsovsky, 1928) that was previously named as C.porphyropterus and two other closely related species, C.brunneus (Thunberg, 1815) and C.maritimus Mistshenko, 1951. We compare them because the calling song of C.miramae was previously shown to have song elements similar to those of other two species. One morphological character, the length of stridulatory file, appeared to be the best character to distinguish between all three species. For C.maritimus and C.miramae, we present the morphological descriptions since they are absent in the literature. We also establish the synonymy C.maritimus = C.bornhalmi Harz, 1971, syn. n. = C.biguttuluseximius Mistshenko, 1951, syn. n. In the song analysis, we analyse not only the sound but also the leg-movement pattern, which is very helpful to find a homology between various song elements. We show that the calling song of C.miramae usually contains two elements, one element being similar to the C.brunneus calling song, and another – to the C.maritimus calling song. Despite some similarities, the calling song elements in C.miramae have some peculiarities. The courtship song of C.miramae is similar to the C.brunneus song, whereas the rivalry songs of C.miramae comprise both the maritimus-like elements and the unique ones. C.miramae generally demonstrates a richer song repertoire than the other two species.