HOFFART, C.*; HILL, P.S.M.: Morphological and Molecular Phylogenetic Analyses of the Gryllotalpidae: What Came First, the Chirp or the Trill?
The prairie mole cricket (Gryllotalpa major) is a burrowing insect native to the tallgrass prairies of the southern United States. The male produces a loud, long-range calling song at sunset in April and May by rubbing the plectrum of one wing along the file of the other wing. The sound produced is a series of chirps. The wing morphology of G. major was compared with five other mole cricket species found in North America: N. hexadactyla, G. gryllotalpa, S. abbreviatus, S. vicinus, S. borellii. The overall wing structures among the crickets were similar, yet calling songs differ in that G. major and N. hexadactyla chirp while the others trill. S. abbreviatus does not have a calling song. The type of calling song may reflect an adaptation that promotes being heard in a particular habitat and may influence the type of mating system of a species. In addition, DNA sequence data were compared for the same species. A morphological phylogeny and a molecular phylogeny for the Gryllotalpidae were constructed to determine if the different species express a similar trait because they inherited it from a common ancestor or because they acquired it independently. The phylogenies account for the history of character change and allow for hypotheses to be developed regarding the course of the mole crickets’ evolution and the correlation of this with behavior traits.