Evolution of Multimodal Courtship Behaviour in the Grasshopper Subfamily Gomphocerinae (Orthoptera, Acrididae)

ABSTRACT The evolution of courtship behaviour in Gomphocerinae was evaluated via estimating a phylogenetic signal and an ancestral character state reconstruction of the song and visual characters. Analyses of courtship behaviour in 85 species allowed us to define five universal characters reflecting general complexity of courtship. A more detailed parameterization of courtship was made for the tribe Stenobothrini, for which 11 characters were selected. The universal characters were found to be conservative in their evolution; by contrast, all characters of the Stenobothrini courtship were shown to be relatively labile. Our study suggests independent evolution of complex courtship in three groups: in Stenobothrini, in Chorthippus albomarginatus group, and several times in the group including subgenus Glyptobothrus ( Ch. biguttulus group and other species) and the genera Gomphocerippus , Gomphocerus , Italohippus , Stauroderus and Megaulacobothrus . The common ancestor of Stenobothrini was shown to generate a complex courtship song that differed from the calling song and comprised two elements. For subgenus Glyptobothrus and associated species, the courtship complexity not only increased, but also decreased, which could be explained by changes in mate‐searching strategies. Our study suggests that visual courtship signals evolved after the appearance of the complex courtship songs consisting of several sound elements. An estimation of the likelihood of transition from one state to another showed that subsequent sound or visual elements appeared with a higher probability than the previous one, although evolution has most likely stabilized at the level of five elements for song and four elements for visual display.