Properties of the pulse filter of females of <i>Steppengrille G. spec./assimilis</i> in comparison with song data.

<p><b>a</b> Envelope of the song pattern of a male (inset: expanded chirp). <b>b</b> Transfer function of the phonotactic response for females to envelope patterns with different modulation frequencies. Presented stimuli consisted of continuous, sinusoidal modulations (open circles) or groups i.e. chirps of sinusoidal pulses (open squares, presented with a chirp duration of 100 ms and chirp period of 500 ms). Envelopes of all stimuli were filled with a carrier of 5.0 kHz. For comparison the pulse filter of the cricket, <i>G. bimaculatus</i>, is shown (gray line). <b>c</b> Selectivity of females for stimuli with rectangular (open squares) or sinusoidal pulses (open diamonds) presented in chirps as in <b>a</b> (pulse duty cycle of 0.5, chirp duration 100 ms, chirp period: 500 ms; for comparison the pulse filter of the cricket, <i>G. bimaculatus</i>, is also shown (gray line)). Histogram shows the distribution of pulse periods measured from individual male songs (c.f. <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0043975#pone-0043975-t002" target="_blank">table 2</a>). <b>d</b> Response profile of females for patterns with different combinations of pulse and pause durations (stimuli consisted of chirps of 100 ms duration presented at a chirp period of 500 ms). Open squares indicate test stimuli with rectangular pulses, open circles refer to stimuli with sinusoidal pulses. <b>e</b> Pulse and pause durations (mean and standard deviation) from song patterns of individual males plotted within the response profile shown in <b>d</b>. Response ranges from <b>d</b> are shown for values of relative phonotaxis at 0.25 (blue line) and 0.75 (red line). <b>f</b> Responses of females to pulse patterns with different duty cycles tested with stimuli that contained only 2 (open circles) or 3 pulses per chirp (open squares) presented at a constant pulse period of 33 ms. For comparison responses of <i>G. bimaculatus</i> are indicated (gray line). The distribution of duty cycles measured from individual song data are shown as black bars. <b>g</b> Responses of females to pulse patterns with only 2 (open circles) or 3 pulses per chirp (open squares) presented at different pulse periods. Chirp period was kept constant at 500 ms. Responses to patterns with a constant chirp duration are shown for comparison (black circles, from <b>c</b>). For a pulse period of 25 ms the number of pulses in a chirp (2p, 3p and 4p) are indicated. Data is given as mean values and standard deviation. Gray stippled lines in panels <b>b, c, f, g</b> mark levels of significance, see methods.