First report on a multiple sex chromosome system (X₁X₂X₃0) and population variations in the frequency of ring bivalents in Pyrrhocoridae (Hemiptera: Heteroptera)

Abstract

Abstract. The family Pyrrhocoridae (Hemiptera: Heteroptera) is characterized by a modal diploid chromosome number of 16 (♂) ranging from 12 to 33 and simple (X0), multiple (X 1 X 2 0) and neo-sex chromosome systems (neoX-neoY). Out of about 340 known species, only 22 species belonging to 7 genera have to date been cytogenetically analysed. In the present study, the chromosome complement and meiotic details of one species, Odontopus nigricornis Stål has been revised, whilst that of another species, Antilochus russus Stål has been cytogenetically analyzed for the first time. The diploid chromosome complement of O. nigricornis is 2n (♂) = 25 = 22A + X 1 X 2 X 3 0; the first time this particular multiple sex chromosome system has been reported in the Pyrrhocoridae. Three sex chromosomes mostly remain intimately associated during male meiosis and their number was confirmed at diplotene and anaphase II, where they dissociate slightly to become distinct. Meiosis is post-reductional for sex chromosomes. However, unlike other pyrrhocorids with multiple X chromosomes, the X 1 , X 2 and X 3 lie outside the autosomal ring on the metaphase plate during both divisions. The male diploid chromosome complement of A. russus was found to be 2n = 27 = 26A + X0. Apart from the typical meiotic features of heteropterans, the latter species shows inter-and intra-population variations in frequency of ring bivalents.

Fissions, fusions, and translocations shaped the karyotype and multiple sex chromosome constitution of the northeast-Asian wood white butterfly,Leptidea amurensis

“…They form univalents that associate with each other during meiotic prophase and it is considered that they originated as a result of nondisjunction of an ancestral X chromosome (Král et al ., ). Similarly, three X chromosomes were recently reported in a heteropteran insect but, in this case, they probably originated as a result of fragmentation (Kaur & Gaba, ). Nevertheless, known meiotic multiples of more than four sex chromosomes are confined to invertebrates and monotremes.…”

Comparative analysis of chromosome numbers and sex chromosome systems in Paraneoptera (Insecta)

“…Besides, a great number of research papers have been published too (e.g. Panzera et al 2010 , 2012 ; Kuznetsova et al 2012 ; Bardella et al 2012 , 2013 , 2014 ; Chirino et al 2013 , 2017 ; Sadílek et al 2013 , 2019a , 2019b , 2020 ; Chirino and Bressa 2014 ; Pita et al 2014 , 2016 ; Kaur and Gaba 2015 ; Stoianova et al 2015 ; Golub et al 2016 , 2017 , 2018 ; Angus et al 2017 ; Gallo et al 2017 ; Grozeva et al 2019 ; for other references see aforementioned reviews). As a result, the number of karyotyped species increased significantly and knowledge about karyotypes and their evolution in true bugs was expanded.…”

On the Origin of Neo-Sex Chromosomes in the Neotropical Dragonflies Rhionaeschna bonariensis and R. planaltica (Aeshnidae, Odonata)

“…In insects with holokinetic chromosomes, multiple sex chromosome systems can also result from fragmentation of sex chromosomes, as has been described for Lepidoptera (WZ/ZZ, female/male) and Heteroptera (XY/XX, male/female) [19][20][21][22][23][24][25]. However, such an origin of multiple sex chromosomes has not yet been reported for Odonata.…”