First record of an atypical and non-stridulatory sound produced by the larvae of two species of Dichotomius (Coleoptera: Scarabaeidae) from Argentina

Abstract

The following study presents the first record of an atypical sound never reported before produced by the larvae of two species of dung beetles from Argentina, Dichotomius (Luederwaldtinia) carbonarius (Mannerheim 1829) and Dichotomius (Luederwaldtinia) nisus (Olivier 1789). This new sound is produced by the larvae in their three instars by shaking the third pair of legs inside the pupation chamber, which does not involve a stridulatory mechanism. Recorded sounds and video images of the larval behaviour are provided. The oscillograms, spectrograms and possible functions are analysed, and a new soundproduction mechanism is postulated.