Meiotic chromosomes and nucleolar behavior in testicular cells of the grassland spittlebugs Deois flavopicta, Mahanarva fimbriolata and Notozulia entreriana (Hemiptera, Auchenorrhyncha)

Abstract

Spittlebugs annually infest pastures and cause severe damage, representing a serious problem for the tropical American beef cattle industry. Spittlebugs are an important biotic constraint to forage production and there is a lack of cytogenetic data for this group of insects. For these reasons, we conducted this work, in which the spermatogenesis and nucleolar behavior of Deois flavopicta, Mahanarva fimbriolata and Notozulia entreriana were studied. The males possessed testes in the shape of a “bunch of grapes”; a variable number of testicular lobes per individual and polyploid nuclei composed of several heteropycnotic bodies. A heteropycnotic area was located in the periphery of the nucleus (prophase I); the chiasmata were terminal or interstitial; metaphases I were circular or linear and anaphase showed late migration of the sex chromosome. The chromosome complement had 2n = 19, except for N. entreriana (2n = 15); the spermatids were round with heteropycnotic material in the center and elongated with conspicuos chromatin. The analysis of testes after silver nitrate staining showed polyploid nuclei with three large and three smaller nucleolar bodies. Early prophase cells had an intensely stained nucleolar body located close to the chromatin and another less evident body located away from the chromatin. The nucleolar bodies disintegrated during diplotene. Silver staining occurred in two autosomes, in terminal and subterminal locations, the latter probably corresponding to the nucleolus organizer regions (NORs). The spermatids were round with a round nucleolar body and silver staining was observed in the medial and posterior region of the elongated part of the spermatid head.

Transcriptional Activity of Translocated NORs in Barley (Hordeum VulgareL.)

“…Similar results were observed in translocation line ab (T [6][7] ab) where the presence of the tandemly arranged noR6h and part of noR5h on the short arm of one chromosome results in strong suppression of noR5h activity. Analysis of somatic cells of ab revealed four AgnoRs (Fig.…”

“…inversions (12)) or without additional chromosome reorganization (1, 38, 39, 52) also showed no nucleolar dominance. the absence of the third pair of AgnoRs may be due to the low level of transcription that cannot be detected (26,27) or due to the extremely high compactisation of the chromatin during metaphase, which do not allow the interactions of silver ions with the protein acidic residues (6).…”

Karyotypes and Repetitive DNA Evolution in Six Species of the Genus <b><i>Mahanarva </i></b>(Auchenorrhyncha: Cercopidae)

“…Invariably, the 7 Mahanarva species studied until now share 2n = 19, X0 ♂ , and this could represent the plesiomorphic character for the genus, which is also observed in other Cercopidae species, such as D. flavopicta [Castanhole et al, 2010], although other additional species should be karyotyped. Considering the ancestral diploid number for Cercopoidea, i.e., 2n = 26-28 [Kuznetsova and Aguin-Pombo, 2015], Mahanarva has a derived constitution that originated most parsimoniously through chromosomal fusions, leading to a reduction in 2n.…”

“…For Cercopidae, ∼ 31 species were karyotyped showing variability for diploid number and sex chromosomes, e.g., 2n = 28, XY ♂ in Cosmoscarta species (C. dimidiata , C. septempunctata , C. decisa , C. egens , and C. fulviceps) ; 2n = 19, X0 ♂ in Mahanarva fimbriolata , M. posticata, and Deois flavopicta ; and 2n = 15, X0 ♂ in Notozulia entreriana [Dey, 1991;Marin-Morales et al, 2002;Castanhole et al, 2010].…”

The first assess of the haplotypes from COI gene sequences in species of spittlebugs (Cicadomorpha: Hemiptera) and aquatic true bugs (Gerromorpha and Nepomorpha: Hemiptera) in Brazil

“…Approximately 1500 species in 150 genera have so far been described in this family (Liang and Webb, 2002), where they are distributed mainly in tropical and subtropical regions. Of these, approximately 400 species are present in South America, with several important pests of forage grasses and sugar cane (Costes and Webb, 2004;Castanhole et al, 2010). In Brazil, these sharpshooters are also pests of sugar cane and pastures, and are therefore of great importance for biological control studies and systematics (Milanez et al, 1983;Zanol, 1996).…”