Recherches sur la phylogénie du genreSaga(Orthoptera: Tettigoniidae): données chromosomiques

Michèle Lemonnier-Darcemont, Anne-Marie Dutrillaux, Bernard Dutrillaux, Christian Darcemont
2008 Annales de la Societe Entomologique de France  
Studies on the phylogeny of the genus Saga (Orthoptera: Tettigoniidae): chromosomic data. Combining the fi rst cytogenetic analysis of four European Saga species, and the re-assessment of the karyotype of Saga pedo (Pallas 1771), with published data and the results of investigations in the fi eld, a phylogeny of the species included is proposed. The most ancestral karyotypes seem to be those of Saga ornata Burmeister 1839 and Saga cappadocica Werner 1903, with all autosomes being acrocentrics.
more » ... he merge of two pairs of their chromosomes resulted in the karyotypes of Saga natoliae Serville 1839 and Saga hellenica Kaltenbach 1967, including one pair of large submetacentrics. These two karyotypes differ by a pericentric inversion on these large chromosomes, that probably took place in S. natoliae. Saga campbelli Uvarov 1921 and Saga rammei Kaltenbach 1965, got an additional chromosomic merge and therefore include two pairs of large submetacentrics. The karyotype of S. rammei has an additional distinctive feature in its heterochromatin. The karyotype of S. pedo is tetraploid, probably the result of juxtaposition of two diploid genomes as a result of hybridisation. The distinctive feature in heterochromatin of S. rammei is found on S. pedo into two distinct chromosomes. Although one could expect quadruplets or doublets of chromosomes, a wide diversity of single chromosomes was noted. This demonstrates that a high rate of chromosomal restructuring has modifi ed the karyotype of S. pedo, after its transition to tetraploidy. These accumulated restructuring, resulting in a high heterozygocity, can be explained by the lack of meiotic barrier for this parthenogenetic species. During our recent research in the fi eld in the south of Balkans, an area with a possible intergradation between Saga pedo and some bisexual closely related species was discovered . The chromosome analysis of specimens from this area will be a main subject for the continuation of our research.
doi:10.1080/00379271.2008.10697583 fatcat:ltwigtellrbbrd7fun6cpoaxvm