Chorthippus Chorthippus karelini

Calling song (Figs 34–39) When producing the calling song, the male of karelini vibrates with the legs in a relatively simple pattern similar to the one of albomarginatus and oschei pusztanesis . During the main part of a song, the legs move alternately, each leg at a rate of about 45–60/s in k. karelini and at a rate of 70/s in karelini bruttius . In k. karelini, a first loud pulse and several subsequent quiet pulses are sometimes separated from the following pulses of a song by a pause. However, this feature may vary individually. The sound pulses of the main part of each song follow at a rate of 90–120/s in the nominate subspecies and at a higher rate of 130–140/s in k. bruttius .

Courtship song (Figs 60–71, App. 2) The courtship song of Ch. k. karelini was analyzed on the basis of recordings from Ukraine (Askania- Nova), Russia (Volgograd region) and Turkey (Erzu- rum). The leg-movement pattern producing A and B elements in the nominate subspecies is quite different from that in Ch. albomarginatus and oschei . During B element, the legs vibrate at a rate of about 25–35/s in a complex pattern: every two up and down leg- movements are coupled in a characteristic way (Figs 64–66). During the A element, the legs vibrate at a much lower rate of 12–15/s and in a simple way. During the A element, the two legs vibrate syn- chronously, whereas during the B element, the legs vibrate with a phase shift. Oscillographic analysis shows that the sound elements A consist of the well- pronounced pulses repeated at a rate of 16–32/s, whereas the sound elements B contain the dense pulses following without gaps. After 30–50 alterna- tions of A/B pairs, a complex of B1-A1-C elements follows. The B1 element of k. karelini is remarkably long, reaching 5–8 s in duration. As a rule, the dura- tion of B elements increases from about 150 ms in the beginning of the cycle to about 1.15 s in the end of the cycle. After the long B1 element, a rather short (0.3–0.5 s) A1 element follows; it is produced by the leg vibrations at a rate of about 40/s. The following C element is quite characteristic: it is accompanied by two fast strokes of the legs (Figs 68–71). During the first stroke, a male does not lift its abdomen, and the tibiae are remaining in their normal position; the second stroke, however, is accompanied with lifting of abdomen at an angle of 30° and is produced with the tibiae, similarly to the stroke of oschei . However, in contrast to oschei , the maximal angle between tibia and femur is 30° in k. karelini , and after the second stroke, the legs vibrate in relatively simple patterns. During the first up-stroke, a short (0.1 s) sound pulse is generated, and after the first down-stroke, as a result of high-frequency leg vibrations, an element lasting for 0.1–0.2 s is produced. We distinguish a C1 element produced by the first up-stroke. During the second up-stroke, a short loud pulse is produced, and afterwards, an element lasting for 0.2–0.3 s fol- lows. The first C element is followed by B element, and the A1/C pair is repeated. Sometimes, the third B-A1-C complex may follow, and then A/B pairs alternate again. When a male produces the complex of B1-A1-C elements, the legs always vibrate alter- nately or with a phase-shift; the only exception is when a male produces the strokes. Both strokes are produced with synchronous movements of the two legs. All sound elements, except for A element, con- sist of dense pulses without gaps. The song of Ch. k. bruttius is basically similar to the song of the nominate subspecies. The characteristic leg-movements and sound patterns of B, B1, A1 and C elements are almost identical in the two subspecies. The main difference is the absence of A elements in the songs of k. bruttius (Fig. 67). This element is some- times also poorly pronounced in the songs of some k. karelini specimens, especially in the very begin- ning of each cycle, but it is usually present in the end of the cycle. Another difference is in the period and duration of B elements. In the song of k. bruttius , B elements are on average of shorter duration, and they are repeated at a higher rate than in the k. kare- lini song (Appendix 2). The duration of B element is less variable in k. bruttius than in k. karelini song. [1]

References