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

Tatiana Tarasova,Varvara Vedenina,Dmitry Tishechkin

doi:10.3897/zookeys.1073.75539

Abstract

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.

Highlights

In singing Orthoptera, the song is an important component of reproductive isolation
Since in Russia and adjacent countries C. brunneus, C. maritimus and C. miramae often occur with two other species of the biguttulus group, C. biguttulus and C. mollis, we describe the main morphological differences from the latter two species as well
The names Stauroderus mollis porphyroptera and S. miramae were described by Vorontsovsky (1928a, b) in two papers on grasshoppers from Orenburg published in the same issue

Summary

Introduction

In singing Orthoptera, the song is an important component of reproductive isolation. Acoustic signals are often used in taxonomy, when sibling species are similar in mor phology, but different in songs. In grasshoppers of subfamily Gomphocerinae, the song is produced by stroking the stridulatory file of each hind femur across a raised vein on the fore wing. The stridulatory movements of the two legs often differ in amplitude and pattern, and the legs can exchange roles from time to time, which leads to an increase of song comple xity (e.g., Elsner 1974; Helversen and Elsner 1977; Helversen and Helversen 1994). To distinguish cryptic grasshopper species, the sound recordings and the recordings of the leg movements are used by various authors (Helversen 1986; Gotts berger and Mayer 2007; Vedenina and Helversen 2003, 2009; Willemse et al 2009; Vedenina et al 2012; Tarasova et al 2021)

Methods

Results

Conclusion