A Perfect Duet? The Acoustic Behaviour Of Anaulacomera Almadaenis Sp. Nov., A Species With An Unusual Chromosome Complement, Discovered In The Footsteps Of The Explorers Spix And Martius In Brazil (Orthoptera, Tettigonioidea, Phaneropterinae)

To find a mate, males and females of phaneropterine bush-crickets engage in duets. The male starts a duet and a female responds if she is prepared to mate. This pattern is exactly followed in the acoustic communication of a species of the genus Anacaulomera from the State of Bahia in Brazil which we newly describe in this manuscript. However, the male also acoustically defends the duet. As soon as it hears a female response, it adds an additional component to its own signal to make the localisation of the female difficult for rivals. At the same time the male reduces the interval between its songs for a faster exchange of information about the location of the partner, and reduces the intensity of the song that it can be heard only from nearby. Besides the nearly perfect anti-eavesdropping modifications of the duet the new species is remarkable concerning its karyotype. The meiotic behaviour of chromosomes in the male may indicate the origin of a new type of sex determination mechanism.