Isoperla quinquepunctata, CO, 1999

Sandberg, John B. & Stewart, Kenneth W., 2006, Continued Studies Of Vibrational Communication (Drumming) Of North American Plecoptera, Illiesia 2 (1), pp. 1-14 : 10

Isoperla quinquepunctata .

One hundred seven and seventy-eight signals were obtained from one, 1-day old male and female respectively, at 21°C and normal incandescent lighting. The male and female produced long signals or “symphonies” ( Szczytko and Stewart 1979) of repeating 2-way sequences (Range: 2–9), with either the typical female single answer beat following the call (N=69) ( Fig. 12A ), or with her answer beat(s) interspersed within the 1 st, 3 rd, 4 th, 6 th, 8 th, 11 th, 13 th or 15 th (N=2) male interval ( Fig. 12B , first underlined duet). The male called with signals of 7 mode beats; with intervals of 173.6 ± 11.4 ms ( Table 3). The average individual call intervals gradually decreased from 179.9 ms (i1) to 171.0 ms (i6), remained fairly uniform until (i15), then increased to 190.8 ms (i20) ( Table 4). Mode and mean beats per female signal were 1 and 1.0 ± 0.2; mean beat interval was 924.5 ± 254.0. The ♂ - ♀ exchange interval was 98.0 ± 5.2 ms for sequenced and overlapped duets.

In our analyses, we treated the multiple 2-way sequences and overlapped duets individually, instead of the entire “symphony” (underlined duets, Figs. 12A–B ). These duets were separated from one another by consistently longer intervals (279.5 ± 62.4 ms) than typical interbeat call intervals (173.6 ± 11.4 ms).

These results are consistent with Szczytko and Stewart (1979) in terms of general signal description and beats, but differ considerably in beat intervals ( Table 5). We propose that our consistently larger overall-mean-interval differences were due to the inconsistencies between their oscilloscope calibration and our computer, explained above under I. phalerata.

Figures

Figs. 7–13. 7. Perlinella drymo drumming: 3-way exchange, TD = 689-msec. Bar = 500-msec; 8. Hydroperla crosbyi drumming: 3-way exchange, TD = 1491-msec. Bar = 500-msec; 9. Isoperla bifurcata drumming: 2- way duet with female interspersed answer, TD = 647-msec. Bar = 500-msec; 10. Isoperla phalerata 2-way duet, diphasic male call, TD = 2579-msec. Bar = 500-msec; 11. Isoperla sobria drumming: 2-way duet, female interspersed answer not shown, TD = 589-msec. Bar = 500-msec; 12. Isoperla quinquepunctata drumming. (A) Typical “multiple” 2-way duets, indicated by lines below, TD = 6727-msec. Bar = 1000- msec, (B) “Multiple” 2-way duets with female interspersed answer beat in first duet, TD = 1688-msec. Bar = 500-msec; 13. Pteronarcys dorsata drumming: 2-way duet with female interspersed answer, TD = 2652- msec. Bar = 1000-msec.