Title

The phylogeny of katydids (Insecta: Orthoptera: Tettigoniidae) and the evolution of their acoustic behavior

Date of Completion

January 2000

Keywords

Biology, Entomology

Degree

Ph.D.

Abstract

This study presents a hypothesis of the phylogenetic relationships among 195 genera of katydids (Insects: Orthoptera: Tettigoniidae), representing nearly all suprageneric taxa of the family. A phylogenetic analysis based on 331 morphological characters yielded multiple, most parsimonious trees of length 1994. In addition, the first detailed description of katydid endoskeletal anatomy is presented and the evolution of the female acoustic behavior is discussed. ^ The characters used in the analysis included not only characters traditionally used in katydid systematics, but also characters never before evaluated, such as the structure of the tarsi, the thoracic endoskeleton, the internal structure of the ovipositor, and a number of egg characters. Three genera of the families Prophalangopsidae (Cyphoderris) and Anostostomatidae ( Cratomelus and Anabropsis) were used as outgroups. The results of the analysis support a fully basal position for the tribe Bradyporini. The subfamily Bradyporinae sensu Gorochov 1995 appears to be paraphyletic, as there is strong support for the monophyly of the more derived Ephhippigerinae. The subfamily Listroscelidinae is polyphyletic, and the tribes Phlugidini and Phisidini form a monophyletic lineage closely related to the Meconematinae. Several genera of the Listroscelidinae (e. g., Liostethomimus, Terpandrus, Chlorobalius) are more closely related to the Saginae. The Copiphorinae appear to be polyphyletic as well, with some genera (e.g., Caulopsis, Euconocephalus, Ruspolia) forming a monophyletic clade with the Conocephalinae. The subfamilies Austrosaginae, Saginae, and Phaneropterinae are paraphyletic. ^ Based on the results of this analysis the evolution of female stridulation has been reconstructed. Seven different tegminal mechanisms of sound production are known in females of the Tettigoniidae, suggesting several independent evolutionary events leading to female sound production. The most primitive mechanism is female tegminal stridulation of the Bradyporini, which is homologous to that of the males. The Ephippigerinae have evolved a unique mechanism, in which the stridulatory file is located dorsally on the surface of the right tegmen. A similar mechanism, but employing a different vein, appeared independently in the Polyancistrinae. The Pterophyllinae have a mechanism consisting of a tuberculate scraper on the inner margin of the right tegmen, and a field of teeth on the underside of the left tegmen. Other, less complex mechanisms appeared in the Phaneropterinae, Meconematinae, and Pseudophyllinae. ^