Continued Studies Of Vibrational Communication (Drumming) Of North American Plecoptera Author Sandberg, John B. & Kenneth W. Stewart & E-mail: jbs 001 @ unt. edu Author Stewart, Kenneth W. Department of Biological Sciences, University of North Texas, Denton, TX 76203 & E-mail: stewart @ unt. edu stewart@unt.edu text Illiesia 2006 2006-03-08 2 1 1 14 journal article http://doi.org/10.5281/zenodo.4758579 b39773d2-f5ab-46f1-a8e5-dc7f64a9fca6 1854-0392 4758579 Hydroperla crosbyi . Eighty-four and 60 signals were obtained from four and three, 1–5 day old males and females, respectively, at 23°C and 58 FTC. Males and the females produced 2-way (N=56) and 3-way exchanges (N=4). The four males consistently called with two grouped (Bi-grouped) signals. The first group’s range in beat count from 2–4 contains one less and more than previously described by Zeigler & Stewart (1985) . Treating the two call-groups separately, the first contained 3 mode beats (3.0 ± 0.4); with intervals of 45.8 ± 16.6 ms and the second group had 4 mode beats (3.6 ± 0.5); with intervals of 47.4 ± 5.0 ms. The intergroup interval between these groups was 157.7 ± 29.8 ms Overall, males called with two groups containing 7 mode beats (6.6 ± 0.7), with overall intervals of 46.7 ± 11.5 ms ( Fig. 8 , Table 3 ). The individual average call intervals of groups 1 and 2 gradually decreased from 47.4 ms (i1) to 40.2 (i3) and from 49.6 ms (i5) to 45.1 ms (i7) respectively ( Table 4 ). Mode and mean number of beats per female answer signal were 4 and 5.0 ± 1.8; mean beat interval was 64.0 ± 10.4 ms. The ♂ - ♀ exchange interval was 246.8 ms ± 84.4 ms and the male response contained 6 mode beats (4.7 ± 1.5); with intervals of 84.9 ± 19.2 ms. The ♀ - ♂ exchange interval was 39.4.3 ± 48.3 ms.