Karyotype diversity among predatory Reduviidae (Heteroptera)

Abstract

Species of infraorder Cimicomorpha of Heteroptera exhibit holokinetic chromosomes with inverted meiosis for sex chromosomes and high variation in chromosome number. The family Reduviidae, which belongs to this infraorder, is also recognized by high variability of heterochromatic bands and chromosome location of 18S rDNA loci. We studied here five species of Reduviidae (Harpactorinae) with predator habit, which are especially interesting because individuals are found solitary and dispersed in nature. These species showed striking variation in chromosome number (including sex chromosome systems), inter-chromosomal asymmetry, different number and chromosome location of 18S rDNA loci, dissimilar location and quantity of autosomal C-heterochromatin, and different types of repetitive DNA by fluorochrome banding, probably associated with occurrence of different chromosome rearrangements. Terminal chromosome location of C-heterochromatin seems to reinforce the model of equilocal dispersion of repetitive DNA families based in the “bouquet configuration”.

Further evidence for the variability of the 18S rDNA loci in the family Tingidae (Hemiptera, Heteroptera)

“…Some other true bug families also demonstrate interspecies difference in size of sex chromosomes (Bardella et al 2014, Fairbairn et al 2016). One of the important sources of chromosome size variability seems to be related to the constitutive heterochromatin variation (White 1973).…”

Analysis of the karyotype structure in Ricolla quadrispinosa (Linneus, 1767): inferences about the chromosomal evolution of the tribes of Harpactorinae (Heteroptera, Reduviidae)

“…Also in metaphase II it is possible to notice several AT rich blocks occupying the terminal and, rarely, interstitial regions of the autosomes. Different patterns of heterochromatin have been reported in other 5 Harpactorinae species (Bardella et al 2014). Thus in Apiomerus lanipes (Fabricius, 1803) the presence of terminal C-DAPI + /CMA 3 + bands in the terminal region was shown, and the heterochromatic sex chromosomes of this species exhibit different florescent patterns.…”

“…Observing Figure 2, it is possible to note that an autosome fusion event (event A) would have given rise to the karyotypes of the species with 2n = 12 + XY, and then a second fusion event (event B) would have originated the karyotypes of the species with 2n = 10 + XY. These karyotypes are observed in Montina confusa (Stål, 1859) (Bardella et al 2014) and two species of the genus Polididus Stål, 1858 (Banerjee 1958, Manna and Deb-Mallick 1981), respectively. This result can be confirmed by molecular analysis, where these genera are grouped forming a separate clade within Harpactorinae (Zhang and Weirauch 2014).…”

“…Also in this branch, chromosomal fusion events (D event) would originate the karyotypes with 2n = 18 + XY (Fig. 2), observed in Repipta flavicans (Amyot and Serville, 1843) (Bardella et al 2014). Phylogenetically Zelus and Repipta are close (Zhang and Weirauch 2014) and occupy a separate branch within the Harpactorini distant from other species with simple sex systems, which allows us to put them in this position with respect to the karyotypic evolution.…”

“…In Cosmoclopius nigroannulatus Stål, 1860 and Zelus laticornis (Herrich-Schaeffer, 1853) only one of the sex chromosomes in each species was totally DAPI + and CMA 3 + in each species. Repipta flavicans (Amyot & Serville, 1843) has not demonstrated fluorescent bands in autosomes and sex chromosomes (Bardella et al 2014). Thus, in Harpactorinae a wide variety of different patterns of C-heterochromatin distribution between the chromosomes was revealed, that implying a large divergence in the karyotypic evolution of species of this subfamily.…”