PHYLOGENETIC-RELATIONSHIPS OF THE TROPIDUCHIDAE-GROUP (HOMOPTERA, FULGOROIDEA) OF PLANTHOPPERS INFERRED THROUGH NUCLEOTIDE-SEQUENCES

Phylogenetic reconstruction of the relationships within the Tropiduchi dae-group of families of planthoppers is conducted based on DNA sequen ces of 2 mitochondrial genes. The sequence comparisons of 400 bases of the 3' end of the 16S rDNA genes from 9 taxa of 6 families and 120 co dons of the 5' end of the cytochrome b genes from 10 taxa of 6 familie s reveal general congruence. The phylogenetic trees based on these 2 g enes show that Flatidae and Tropiduchidae are always grouped together; Meenoplidae and Delphacidae each is a basal lineage among these taxa, and Issidae is a nonhomogeneous group. The ratio of transitions over transversions of the cytochrome b gene in fulgoroids has reached a ste ady-state when compared with insects of other orders. Both genes can b e candidate genes in studying the relationships of Fulgoroidea since t he sequence Variations of both genes between species of intragenus, cl ose affinity families, and distant affinity families are about 10%, 20 %, and 30%, respectively.