Chorthippus (Chorthippus) ferdinandi Vedenina & Helversen, 2009

Calling song (Figs 42–44, 47–49) The male of ferdinandi produces up to 8 calling songs separated by intervals of 1.5–2 s. A song lasts for about 0.45–0.65 s. A leg-movement pattern pro- ducing a song is of a higher complexity in ferdinandi than in most species of the group: every two up- and-down leg-movements are coupled in such a way that a high-amplitude stroke alternates with a low- amplitude stroke. Oscillographic analysis shows that the sound pulses follow without gaps, and the low- amplitude pulses alternate with the higher-amplitude pulses. However, the sound pattern slightly varies in different populations and the sound pulses may be of about equal loudness.

Courtship song (Figs 75–79, App. 2) The song starts with an alternation of A and B ele- ments, which slightly resembles the correspond- ing elements in k. karelini . In the beginning of the B element of ferdinandi , the legs move synchronously in a rather simple pattern. After the first third of B element, they start to vibrate in a more complex pattern and with a phase-shift, like in karelini, but at a higher rate of 40–50/s. The leg movements produc- ing the A element are much slower (about 5/s) and of a higher amplitude, than during the B element. The legs are moved synchronously during the A element. Oscillographic analysis shows that several louder dis- tinct pulses are sometimes visible in the beginning of the B element, and then quieter pulses without gaps follow. Each A element contains one to three loud pulses pro- duced during the down-strokes, and sometimes one to three very quiet pulses produced during the up-stroke. In contrast, in k. karelini , the leg movements produc- ing A and B elements are of about the same amplitude, and the sound pulses of A element produced by the up- and down-strokes are of equal loudness. In ferdi- nandi , the element C follows after alternating of about 18 A/B pairs. Leg movements producing the C ele- ment represent a peculiar kind of combination of the oschei and karelini leg-movement patterns. Similarly to karelini, the males of ferdinandi produce two rela- tively fast strokes. However, after the second stroke, the legs vibrate in a complex pattern similarly to the pattern of Ch. oschei pusztaensis . During the first stroke, an element of about 100ms-duration is pro- duced (C1 element). Sometimes a loud pulse follows in the beginning of the element (Fig. 78). Thereafter the legs shortly vibrate in a simple pattern at a rate of 40–45/s and produce a quiet element of about 100 ms as well. After the second stroke the legs pro- duce a longer element lasting for about 0.7–1 s and containing short distinct pulses following at a rate of 170–220/s. After one C element, the whole cycle is repeated. [1]

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