Isoperla bifurcata, Szczytko & Stewart, Oak Burn Creek, Corvallis, Benton Co., Oregon, 1999

Sandberg, John B. & Stewart, Kenneth W., 2006, Continued Studies Of Vibrational Communication (Drumming) Of North American Plecoptera, Illiesia 2 (1), pp. 1-14 : 6

Isoperla bifurcata .

One hundred thirty-six and 130 signals were obtained from two and one, 2–8 day old males and female, respectively, at 23°C and 65 FTC. Males and females produced 2-way sequenced signals with female answer signals either following the male call (N=48) or with interspersed answer beats beginning during the male’s 4 th (N=15), 5 th (N=42), 6 th (N=24) and 7 th (N=1) interval. The two males called with signals of 6 mode beats (6.2 ± 0.8); with intervals of 50.2 ± 5.7 ms ( Fig. 9 , Table 3). Their average individual intervals gradually decreased from 54.5 ms (i1) to 45.4 ms (i6), then increased to 58.2 ms (i9) ( Table 4). Mode and mean number of beats per female answer signal were 3 and 3.9 ± 2.5; mean beat interval was 50.0 ± 10.0 ms. The ♂ - ♀ exchange interval was 131.6 ± 21.3 ms for sequenced and overlapped duets.

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.