Usefulness of Internal Transcribed Spacer Regions of Ribosomal Dna in Melanopline (Orthoptera: Acrididae) Systematics

The utility of the first internal transcribed spacer (ITS 1) of ribosomal DNA complexes in grasshopper phylogenetics is examined. Polymerase chain reaction amplification of the targeted region in 112 individuals representing 10 different melanopline species always yielded a fragment of ≈500 bp. A small number of insects had one or two extra bands. Sequencing the dominant band in five specimens, three subspecies of Melanoplus sanguinipes (F.), M. gladstoni Scudder, and M. packardii Scudder, showed that the ITS 1 region is ≈360-388 bp in length with a G+C content of ≈63%. Sequences, omitting gaps, were virtually identical among grasshoppers; whereas there were appreciable differences when insertions and deletions were taken into account. Limitations of using this spacer region in grasshopper systematics are discussed.