Substrate-borne vibrations used during acoustic communication and the existence of courtship songs in some species of the genus Anaxipha (Saussure) (Orthoptera: Trigonidiidae: Trigonidiinae)

Abstract

Anaxipha (Saussure, 1874) are small, swordtail crickets found in much of eastern North America. Many species within the genus Anaxipha were only recently described and their calling songs characterized. However, little is known about their courtship songs or use of substrate-borne communication (drumming). This study is the first documentation of the existence of courtship songs and substrate-borne vibrational communication in the genus. Courtship songs and substrate-borne vibrational communication were first detected in the following species: Anaxipha exigua (Say, 1825), A. tinnulacita Walker & Funk, 2014, A. tinnulenta Walker & Funk, 2014, and A. thomasi Walker & Funk, 2014. When in the presence of a conspecific female, males of all four species perform courtship songs that are distinctly different in pattern of echeme delivery and syllable details compared to their respective calling songs. Additionally, males of all four species exhibited drumming behavior during courtship singing and variably during calling songs. Examination of video recordings of males drumming during courtship singing showed that they are apparently using the sclerotized portion of their mandibles to impact the substrate on which they are perched to create vibrations. Courtship song and drumming bout characteristics were statistically different among the four species studied here, although A. tinnulacita and A. tinnulenta were similar in some measurements. Drumming during calling songs was common only in A. tinnulacita, where drumming occurs predominately during the first forty percent and last twenty percent of the long echemes of calling songs. Additional study is needed to further explore the use of substrate-borne vibrational communication in this genus.