Cytogenetics of the darkling beetles Zophobas aff. confusus and Nyctobates gigas (Coleoptera, Tenebrionidae)

Abstract

ABSTRACT. Males of Zophobas aff. confusus and Nyctobates gigas (Tenebrionidae) collected in the State of Pernambuco, Brazil, were studied through conventional staining, C-banding, silver nitrate impregnation (AgNO 3 ), and the base specific fluorochromes CMA 3 and DAPI. Z. aff. confusus was found to have 2n = 20 (9+Xyp) while N. gigas exhibited 2n = 18 (8+neoXY). Large pericentromeric blocks of constitutive heterochromatin (CH) were detected throughout the autosomal complement of the two species, except in one autosomal pair of N. gigas in which no heterochromatic block was observed. The sex chromosomes of both species were almost totally heterochromatic. Double staining with CMA 3 /DA (distamycin) and DAPI/DA marked CH in Z. aff. confusus. However, DAPI staining was more intense. N. gigas was found to possess blocks of CH-positive CMA 3 and homogeneous DAPI. AgNO 3 staining also revealed differences between the two species. In Z. confusus an NOR was observed in the sexual bivalent Xyp and N. gigas was found to have an autosomal NOR.

Chromosome mapping of 28S ribosomal genes in 11 species of Cassidinae (Coleoptera: Chrysomelidae)

“…immaculata the ribosomal cistrons are co-localized with constitutive heterochromatin on the terminal region of the chromosomes. The co-localization of these two chromosomal markers is reported in other coleopteran families, such as Curculionidae, Elateridae, Geotrupidae, Lucanidae, Scarabaeidae and Tenebrionidae (Virkki & Sepúlveda, 1990;Colomba et al, 1996Colomba et al, , 2000aColomba et al, , b, 2004Vitturi et al, 1999Vitturi et al, , 2003Moura et al, 2003;Bione et al, 2005;Schneider et al, 2006;Dutrillaux et al, 2007;Cabral-Mello et al, 2010;Lira-Neto et al, 2012). Cabralde Mello et al (2011a), in their comparison of the number and localization of major rDNA sites with the distribution of constitutive heterochromatin in 22 beetles in the subfamily Scarabaeinae, verifi ed two patterns: (1) a stable number of rDNA sites (one autosomal pair) in species with constitutive heterochromatin predominantly located in the centromeric/pericentromeric region and (2) an increased number of rDNA cistrons in species with constitutive heterochromatin dispersed in the chromosomes.…”

“…The images of the chromosomes were taken using a Zeiss Imager A2 equipped with an Axio Cam digital camera, using Axion Vision software (Carl Zeiss AG, Jena, Germany). Silva et al, 2009;Almeida et al, 2010;Cabral de Mello et al, 2010, 2011aMendes-Neto et al, 2010;Oliveira et al, 2010Oliveira et al, , 2012aGiannoulis et al, 2011;Proença et al, 2011;Lira-Neto et al, 2012;Karagyan et al, 2012;Goll et al, 2013Goll et al, , 2015.…”

Karyotype and sex chromosome differentiation in two Nalassus species (Coleoptera, Tenebrionidae)

“…Heretofore, variation in the diploid chromosome numbers between 14–38 within the family are also noted (Juan and Petitpierre 1991a, Pons 2004, Holecová et al 2008a, Lira-Neto et al 2012). Although, tenebrionid karyotypes characterized with predominant presence of metacentric chromosomes (Guenin 1950, 1951a, b; Smith 1952, Yadav and Pillai 1974, Yadav et al 1980, Juan and Petitpierre 1988, 1989, 1990, Juan et al 1989), several species from different subfamilies have mostly subtelocentric/acrocentric sets (e.g.…”

“…1), which is considered as modal chromosome number for Tenebrionidae (Juan and Petitpierre 1991a, Pons 2004, Holecová et al 2008a, Lira-Neto et al 2012). The presence of heteromorphic sex chromosomes for both species is confirmed by occurrence of a Xy p configuration in both conventionally (Fig.…”

“…Although most species present a karyotype with 2n = 20, the diploid number ranges from 2n = 14 to 2n = 38 (Juan and Petitpierre 1991a, Pons 2004, Holecová et al 2008a, Lira-Neto et al 2012). Chromosomal data are only available for several representatives of subfamilies Lagriinae, Tenebrioninae, Pimeliinae, Alleculinae and Diaperinae mostly distributed in Mediterranean (Juan and Petitpierre 1991a).…”