Isoperla phalerata, 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 phalerata .

Fifty and 28 signals were obtained from one, 1–2 day old male and female, respectively, at room temperature and normal incandescent light. The male and female produced 2-way sequenced signals and the male called with diphasic signals. The male called with 13 mode beats (12.8 ± 0.9); with intervals of 96.6 ± 16.6 ms during first phase and with 22 mode beats (22.2 ± 1.6); with 34.6 ± 5.7 ms during the second phase ( Fig. 10 , Table 3). The first phase average individual intervals decreased from 124.4 ms (i1) to 62.6 ms (i14) and the second phase gradually decreased from 51.3 ms (i1) to 31.0 (i16), then increased to 35.2 ms (i24) ( Table 4). Mode and mean number of beats per female signal were 5 and 5.0 ± 1.0; average beat interval was 109.9 ± 27.7 ms. The ♂ - ♀ exchange interval was 301.0 ± 124.0 ms.

These results for I. phalerata ( Table 3) and those from Sandberg and Stewart (2003) for I. fulva and I. mormona ( Table 6) differ considerably in overall average intervals for the same three species reported by Szczytko and Stewart (1979) ( Table 5). We propose here that their consistently smaller intervals for these three species and those of I. quinquepunctata are probably in large part due to calibration inconsistency in their oscilloscope compared with the probably more accurate calibration of our computer ( Sandberg and Stewart 2003).

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.