Cytogenetics studies in thirteen Brazilian species of Phaneropterinae (Orthoptera: Tettigonioidea: Tettigoniidae): main evolutive trends based on their karyological traits

Abstract

PALAVRAS-CHAVE: Cariótipo, cromossomo, evoluçãoABSTRACT -The thirteen species of Phaneropterinae here studied can be arranged in four different groups according to their basic karyological traits. All of them share the same kind of chromosomal sex determining mechanism with X0♂ and XX♀. The X chromosome differs among species and always appears heteropycnotic during prophase I, it is the largest in the set and segregates precociously during anaphase I. Among the species, the karyotypes varies in fundamental number between 31 to 21. The meaning of these significant changes in the karyotypes in relation to the phylogeny within some large taxonomic group of species is discussed. KEY WORDS: Karyotype, chromosome, evolutionThe family Tettigoniidae includes approximately 1,070 genera and 6,000 species arranged according to different authors, in 14 to 24 subgroups [Kevan 1976[Kevan , 1977[Kevan , 1982Rentz 1985, 1995 (apud Warchalowska-Śliwa 1998; Eades et al. 2002).The subfamily Phaneropterinae comprises a large number of species with wings that mimic leaves. The species are easily recognized by the lack of lateral grooves in the first and second tarsal segments and also because the females show a very short ovipositor curved upwards. The subfamily is found all around the world but it is particularly common in the tropical and subtropical zones.After the first caryological studies of the Phaneropterinae species, published in the beginning of the 20 th century, few progresses were ensued if compared with other orthopteran groups. Except for the subfamily Tettigoniinae, the Phaneropterinae species are the best known cytologically within the family Tettigoniidae. The karyology of 86 species are known including those of the present paper. A recent revision was published by Warchalowska-Śliwa (1998) but the chromosomes of three species studied by Ferreira et al. (1976) were not included in the paper: Thomazia borgmeire (Piza, 1977) and Ferreiraia nigropunctata (Piza, 1977) both with 2n♂ = 31 and Viadana delicatula (Piza, 1977) with 2n♂ = 27, the three species with all the chromosomes acrocentric. Several species described by Warchalowska-Śliwa et al.

Changes in the numbers of chromosomes and sex determination system in bushcrickets of the genus Odontura (Orthoptera: Tettigoniidae: Phaneropterinae)

“…A similar type of translocation, i.e. a biarmed X chromosome (subacro/submeta/metacentric), is reported in some species of the long-winged phaneropterids and of Barbitistini belonging to the genera Isophya, Poecilimon, and Leptophyes (see review in Warchaowska-liwa, 1998;Ferreira & Mesa, 2007;Warchaowska-liwa et al, 2008).…”

Chromosomal diversification in the flightless Western Mediterranean bushcricket genusOdontura(Orthoptera: Tettigoniidae: Phaneropterinae) inferred from molecular data

“…There exists, however, a taxonomic bias in the karyotype data, as the majority of the 86 species for which information is available come from the tribe Barbitistini (Warchałowska-Sliwa 1998). Newer results using several unrelated Phaneropterinae from Brazil (Ferreira and Mesa 2007) strongly point towards the basic karyology (2n = 31) as the ancestral situation, eliminating the Barbitistini bias. Our data also support this karyotype pattern as ancestral, with six outgroup species showing the basic number of 2n♂ = 31.…”

Cytogenetic characterization of Eurysternus caribaeus (Coleoptera: Scarabaeidae): evidence of sex-autosome fusion and diploid number reduction prior to species dispersion

“…In the insect class, as a whole, there are groups that present modal and conserved diploid number, i.e. acridid grasshopper (Orthoptera), Libellulidae (Odonata), and groups less conserved showing variation in number of autosomes and/or sex chromosomes, for example in Phaneropterinae (Tettigoniidae, Orthoptera) and Reduviidae (Heteroptera) (Hewitt 1979;Mola et al 1999;Ferreira and Mesa 2007;Poggio et al 2007).…”