Phylogeny and the evolution of calling songs in Gryllus (Insecta, Orthoptera, Gryllidae)

Acoustic signalling is the most important communication modality for crickets. While it has been studied intensively, few authors have analysed the evolution of cricket acoustic signals within a macroevolutionary perspective, still fewer with respect to its phylogenetic aspects. This may be due in part to the lack of acoustic and phylogenetic data; there are also difficulties involved in applying phylogenetic methods to acoustic data. The most critical aspect may be describing calls using characteristics consistent with current criteria for homology. In this paper we discuss, in relation to the evolution of the North American species of Gryllus , the reliability of these criteria and describe songs using two complementary sets of characters: (i) general structure (carrier frequencies and main temporal features), and (ii) ‘special quality’ (particular features at a lower structural level).