A description of the male drumming call of Besdolus ventralis (Pictet, 1841) (Plecoptera: Perlodidae)

Abstract

This paper gives the first description of the male drumming call of Besdolus ventralis. Based on the examination of a single male specimen of this rare stonefly species its male call is composed of 3 beat groups, each containing 3-6 beats repeated at decreasing interbeat intervals. Beat groups are separated by 184-212 ms intergroup intervals. Call duration varied between 496-549 ms at ambient air temperature 18.7-20.4 degrees of Celsius. These results show that the male call of B. ventralis is clearly different from the diphasic call of B. ravizzarum, and is rather similar to that of B. bicolor, which is the closest relative of B. ventralis regarding mitocondrial DNA sequences. The main difference between the male calls of the two species seems to be that B. ventralis produces 3-6 beats per group, while B. bicolor is reported to produce only 2 (rarely 3) beats per beat-group.