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The cytogenetic characteristics of 17 species of bushcricket belonging to eight genera of the tribe Barbitistini were examined by fluorescence in situ hybridization with 18S rDNA and ([TTAGG.sub.n] telomeric as probes and by C-banding, silver, and fluorochrome staining. These markers were used to understand chromosomal organization and evolutionary relationships between genera or species within the same genus. The number of 18S rDNA clusters per haploid genome that co-localized with active nucleolus organizer regions (NORs) ranged from one to five, with the most common pattern being the presence of one NOR-bearing chromosome. This ribosomal cistron was preferentially located in the paracentromeric region of autosomes and very rarely in the sex chromosome. The results demonstrated coincidence between the localization of major ribosomal genes and active NORs and the position of C-band and GC-rich regions. The rDNA/NOR distribution and the composition of chromosome heterochromatin proved to be good cytogenetic markers for distinguishing species and phylogenetic lines and for understanding the genomic differentiation and evolution of Barbitistini. A comparison of cytogenetic and morphological or behavioral traits suggests that morphological and behavioral specialization in this group was not followed by major karyotype modification (except for Leptophyes). However, the occurrence and distribution of different repetitive DNA sites tends to vary among the taxa. Key words: FISH, rDNA sites, chromosome banding, cytogenetics, Orthoptera. Les caracteristiques cytogenetiques de 17 especes de barbitistes (<>) appartenant a huit genres de la tribu des Barbitistini ont ete examinees par hybridation in situ en fluorescence en utilisant comme sondes les ADNr 18S et les sequences telomeriques (TTAGGJ de meme que par marquage des bandes C, a l'argent ou au fluorochrome. Ces marqueurs ont ete employes pour decrire l'organisation des chromosomes et les relations evolutives entre les genres et entre les especes au sein d'un meme genre. Le nombre de sites d'ADNr 18S par genome haploide dont la localisation coincidait un organisateur nucleolaire (NOR) actif variait entre un et cinq, la situation la plus courante etant d'avoir un seul chromosome portant un NOR. Ce cistron ribosomique etait le plus souvent situe dans la region paracentromerique des autosomes et tres rarement sur le chromosome sexuel. Les resultats ont demontre une co-localisation des principaux genes ribosomiques et des NOR actifs avec la position des bandes C et des regions riches en GC. La distribution des ADNr/NOR et la composition de l'heterochromatine se sont averes de bons marqueurs cytogenetiques pour distinguer les especes et les lignages phylogenetiques ainsi que pour comprendre la differenciation genomique et l'evolution au sein des Barbitistini. Une comparaison des caracteres cytogenetiques et morphologiques ou comportementaux suggere que la specialisation morphologique ou comportementale au sein de ce groupe n'a pas ete suivie par une modification caryotypique (a l'exception des Leptophyes). Cependant, la presence et la distribution de sequences repetitives semble varier entre les taxons. [Traduit par la Redaction] Mots-cles: FISH, sites d'ADNr, coloration des chromosomes, cytogenetique, Orthoptera., Introduction Phaneropterinae is the most species-rich subfamily of bushcrickets, encompassing 14 tribes, 339 genera, and more than 2300 species occurring predominantly in the tropics. The flightless bushcricket tribe Barbitistini, distributed [...]

Research has been conducted on Eyprepocnemidinae grasshoppers from Russia and Central Asia. The Authors demonstrate that chromosomal localization of ribosomal DNA and satellite DNA isoalted from Spanish grasshoppers have been analyzed in Russian and Central Asian species in order to understand the evolution of the chromosome markers in this group of grasshoppers, and they discuss the results.