Allozyme divergence and phylogenetic relationships among species of tephritid flies

Abstract

Multilocus enzyme electrophoresis data from 24 orthologous loci (212 alleles) were used to infer the genetic similarities between 11 Tephritidae pest species from the Ceratitis, Trirhithrum, Capparimyia, Bactrocera, Anastrepha and Rhagoletis genera. Within some of the considered species, different degrees of genetic variability were demonstrated, which appear to be related to zoogeography and to the biological traits peculiar to each species. Nei (1978) and Cavalli-Sforza & Edwards (1967) genetic distances were used to express the genetic divergence and to infer phylogenetic relationships among the species. The upgma clustering algorithm and the optimality criteria of Fitch & Margoliash (1967), with (kitsch) and without (fitch) the tree constrained to have contemporary tips, were used. All the methods indicate the same clusters of species. One cluster is composed of Ceratitis capitata, Trirhithrum coffeae and Capparimyia savastanoi, another is composed of Rhagoletis cerasi, Bactrocera dorsalis and Bactrocera oleae. A further loose cluster is comprised of Ceratitis rosa and Anastrepha spp. The congruence between electrophoretic phylogeny and morphological classification is discussed. Our analysis also elucidated cases, within the Ceratitis and Bactrocera genera, of interest from the evolutionary point of view, where allozyme dendrograms do not correlate well with morphological taxonomic relationships.