Isoperla sobria, OR, 2004

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 sobria .

This species from a new location was analyzed individually during 2001 and 2004. A total of 99 and 20 signals were obtained from two 3-11 day old males and females, respectively. Recording occurred at room temperature and normal incandescent light in 2001 and 23–24°C and 84 FTC in 2004. In both years, males and females produced 2-way sequenced signals with either the female answer signal following the call (N=12), or with the beginning answer beats interspersed within the males 2 nd (N=1), 3 rd (N=3), 4 th (N=3) and 5 th (N=1) interval. In 2001, the male called with 4 mode beats (3.7 ±0.8); with intervals of 159.1 ± 7.2 ms and in 2004, with 6 mode beats (5.2 ± 1.0); with intervals of 151.1 ± 5.8 ms ( Fig 11 , Table 3). The 2001 average individual intervals gradually decreased from 162.4 ms (i1) to 156.1 ms (i2), then increased to 163.1 ms (i4) ( Table 4). The 2004 average individual intervals gradually decreased from 152.4 ms (i1) to 147.7 ms (i2), then increased to 154.6 ms (i6) ( Table 4). The 2001 mode and mean number of beats per female answer signal were 1 and 1.1 ± 0.2; beat interval was 62.9 ms (N=1). The 2001 ♂ - ♀ exchange interval was 99.8 ± 5.6 ms for sequenced and overlapped duets. The 2004 female answer signals contained only a single interspersed beat and the ♂ - ♀ exchange interval was 112.8 ± 4.0 ms. These results agree well within reasonable expected variation, with those of Sandberg and Stewart (2003) and do not suggest a new dialect.

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.