The songs and taxonomy of the grasshoppers of the Chorthippus biguttulus group in the Iberian Peninsula (Orthoptera: Acrididae)

The Chorthippus biguttulus group includes a number of common European species that are difficult to distinguish morphologically but are easily recognized in the field by the distinctive calling songs of the males. These song-patterns have not previously been studied in Spain and as a result the Iberian members of the group have been misidentified in almost all the extensive Spanish literature on the ecology and cytogenetics of these insects. In this study the male calling songs of all six members of the group known from the Iberian Peninsula and North Africa are fully described and illustrated with oscillograms at several different speeds. The songs of the three species known only from Iberia or North Africa, jacobsi, yersini and marocanus, are fully described for the first time (marocanus is here raised in rank from subspecies). Notes on recognition, using both morphology and song, are given for each species, and two identification keys are provided, one based on morphology and the other on song. It is shown that the three species biguttulus, brunneus and mollis, previously believed to be widespread in Iberia, are absent from most of the peninsula.